[Effect of Echinococcus multilocularis infection on Tim3 expression in spleen natural killer cells of mice].

OBJECTIVE: To investigate the effect of Echinococcus multilocularis infection on Tim3 expression and its co-expression with immune checkpoint molecules 2B4 and LAG3 in spleen natural killer (NK) cells of mice. METHODS: C57BL/6 mice, each weighing (20 ± 2) g, were randomly divided into a high-dose infection group (15 mice), a low-dose infection group (13 mice), and a control group (11 mice). Mice in the high- and low-dose infection groups were inoculated with 2 000 and 50 Echinococcus multilocularis protoscolices via the hepatic portal vein, while animals in the control group was injected with an equivalent amount of physiological saline via the hepatic portal vein. Mouse spleen cells were harvested 12 and 24 weeks post-infection, and Tim3 expression and its co-expression with 2B4 and LAG3 in NK cells were detected using flow cytometry. RESULTS: There were significant differences in the proportions of Tim3 expression (F = 13.559, P < 0.001) and Tim3 and 2B4 co-expression (F = 12.465, P < 0.001) in mouse spleen NK cells among groups 12 weeks post-infection with E. multilocularis, and the proportion of Tim3 expression was significantly higher in mouse spleen NK cells in the low-dose infection group [(23.84 ± 2.28)%] than in the high-dose infection group [(15.72 ± 3.67)%] and the control group [(16.14 ± 3.83)%] (both P values < 0.01), while the proportion of Tim3 and 2B4 co-expression was significantly higher in mouse spleen NK cells in the low-dose infection group [(22.20 ± 2.13)%] than in the high-dose infection group [(14.17 ± 3.81)%] and the control group [(15.20 ± 3.77)%] (both P values < 0.01). There were significant differences in the proportions of Tim3 expression (F = 5.243, P < 0.05) and Tim3 and 2B4 co-expression (F = 4.659, P < 0.05) in mouse spleen NK cells among groups 24 weeks post-infection with E. multilocularis infection, and the proportions of Tim3 expression and Tim3 and 2B4 co-expression were significantly lower in mouse spleen NK cells in the high-dose infection group [(20.55 ± 7.04)% and (20.98 ± 7.12)%] than in the control group [(31.38 ± 3.19)% and (31.25 ± 3.06)%] (both P values < 0.05), and there were no significantly difference between the proportions of Tim3 expression and Tim3 and 2B4 co-expression in splenic NK cells in the low-dose infection group [(26.80 ± 6.47)% and (26.48 ± 6.48)%] and the control group (both P > 0.05). There were no significant differences in the proportions of Tim3 and LAG3 co-expression in mouse spleen NK cells among groups 12 (F = 2.283, P > 0.05) and 24 weeks post-infection (F = 0.375, P > 0.05). In the low-dose infection group, there were no significant differences in the proportions of Tim3 expression or Tim3 and 2B4 co-expression in mouse spleen NK cells 12 (t = -1.137, P > 0.05) or 24 weeks post-infection (t = -1.658, P > 0.05), and the proportion of Tim3 and LAG3 co-expression increased in mouse spleen NK cells 24 weeks post-infection relative to 12 weeks post-infection (t = -5.261, P < 0.01). In the highdose infection group, there was no significant difference in the proportion of Tim3 expression in mouse spleen NK cells 12 and 24 weeks post-infection (t = -1.546, P > 0.05); however, the proportions of Tim3 co-expression with 2B4 and LAG3 increased in mouse splenic NK cells 24 weeks post-infection relative to 12 weeks post-infection (t = -2.425 and -4.745, both P values < 0.05). CONCLUSIONS: The Tim3 expression and Tim3 co-expression with LAG3 and 2B4 on spleen NK cells is affected by doses of E. multilocularis infection and disease stages, and present different phenotypes during the course of alveolar echinococcosis. NK cells tend to form an immunosuppressive phenotype with the progression of E. multilocularis infection, which facilitates immune escape and chronic parasitism of E. multilocularis.

[Research progress on the role of glucose in regulating immune homeostasis].

Glucose is the central nutrient for energy metabolism and life support in the human body. As the main energy substance of the body, glucose is essential for the normal function of immune cells and their proliferation; when glucose homeostasis is disrupted in the body, it may lead to impaired immune system function and pathological conditions. Exploring the relationship between glucose metabolism and immune regulation can help establish the gene regulatory network and figure out potential pathogenic mechanisms under physiological and pathological conditions. This article reviews the current scientific research progress on glucose metabolism and immunity, mainly focusing on the physiological regulatory functions of glucose in maintaining the homeostasis of innate and acquired immunity; and summarizes the research progress on the effects and mechanisms of glucose on tumor immunity and its related therapies under pathological conditions, taking tumors as an example.

[The role of intravoxel incoherent motion diffusion-weighted imaging in distinguishing diabetic nephropathy from non-diabetic renal disease in diabetic patients].

Objective: To investigate the intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) in the differential diagnosis of diabetic nephropathy (DN) and non-diabetic renal disease (NDRD) among patients with type 2 diabetes mellitus (T2DM). Methods: A diagnostic test. In this prospective study, patients with T2DM who underwent both IVIM-DWI and renal biopsy at the First Medical Center of Chinese PLA General Hospital between October 2017 and September 2021 were consecutively enrolled. IVIM-DWI parameters including perfusion fraction (f), pure diffusion coefficient (D), and pseudo-diffusion coefficient (D*) were measured in the renal cortex, medulla, and parenchyma. Patients were divided into the DN group and NDRD group based on the renal biopsy results. IVIM-DWI parameters, clinical information, and diabetes-related biochemical indicators between the two groups were compared using Student's t-test or Mann-Whitney U test. The correlation of IVIM-DWI parameters with diabetic nephropathy histological scores were analyzed using Spearman's correlation analyzes. The diagnostic efficiency of IVIM-DWI parameters for distinguishing between DN and NDRD were assessed using the receiver operating characteristic (ROC) curves. Results: A total of 27 DN patients and 23 NDRD patients were included in this study. The DN group comprised 19 male and 8 female patients, with an average age of 52±9 years. The NDRD group comprised 16 male and 7 female patients, with an average age of 49±10 years. The DN group had a higher D* value in the renal cortex and a lower f value in the renal medulla than the NDRD group (9.84×10-3 mm2/s vs. 7.35×10-3 mm2/s, Z=-3.65; 41.01% vs. 46.74%, Z=-2.29; all P<0.05). The renal medulla D* value was negatively correlated with DN grades, interstitial lesion score, and interstitial fibrosis and tubular atrophy (IFTA) score (r=-0.571, -0.409, -0.409; all P<0.05) while the renal cortex f value was positively correlated with vascular sclerosis score (r=0.413, P=0.032). The renal cortex D* value had the highest area under the curve (AUC) for discriminating between the DN and NDRD groups (AUC=0.802, sensitivity 91.3%, specificity 55.6%). Conclusion: IVIM-derived renal cortex D* value can be used non-invasively to differentiate DN from NDRD in patients with T2DM that can potentially facilitate individualized treatment planning for diabetic patients.

Advances in the Construction and Application of Thyroid Organoids.

Organoids are complex multicellular structures that stem cells self-organize in three-dimensional (3D) cultures into anatomical structures and functional units similar to those seen in the organs from which they originate. This review describes the construction of thyroid organoids and the research progress that has occurred in models of thyroid-related disease. As a novel tool for modeling in a 3D multicellular environment, organoids help provide some useful references for the study of the pathogenesis of thyroid disease.

Analysis of Institutional DIBH Coaching Program for Surface Guided-DIBH Patients.

PURPOSE/OBJECTIVE(S): Our institute has implemented a surface guided-DIBH (SG-DIBH) coaching program which involves consultation, pre-treatment (CT-sim) and treatment. We would like to analyze the effectiveness of the program. MATERIALS/METHODS: A total of 72 left breast cancer patients between 1st Apr 2022 to 9th Dec 2022 were registered for radiation treatment. During consultation, oncologist selected suitable patients based on the following criteria: a) age of 18-70; b) left breast cancer, right breast cancer with internal mammary nodes irradiation or dextrocardia; c) no lung/cardiac disease history & d) volunteer for SG-DIBH technique. The eligible patients were then trained by the coaching therapist using a teaching video and practiced at home. During CT simulation, patients were assessed according to the DIBH evaluation form. The evaluation components included patient's compliancy and understanding, the differences of lateral skin marking (free breathing, FB vs DIBH), duration of breath hold and reproducibility. Patients who passed the evaluation were scanned under both FB and DIBH for SG-DIBH treatment. IMRT-FFF 6 to 7 fields were planned. During SG-DIBH treatment, first 3 fractions and weekly CBCT were taken. Patients were encouraged to continue DIBH practice at home throughout whole course of the treatment and they were given 3 identical survey forms (5 questions) at the beginning, middle and end of treatment. The measure for the success of this coaching program would be number of breath-holds, duration of treatment time, treatment accuracy (CBCT matching) and survey results. RESULTS: There were 48 patients who were eligible for DIBH coaching program, however, only 24 patients had passed the coaching evaluation and 20 patients were treated with SG-DIBH technique successfully. The mean of number of breath-hold and treatment time was 7 times and 7.9 minutes. Total of 123 CBCT images were studied. The setup errors were (0.242±0.180) cm, (0.152±0.137) cm, (0.202±0.165) cm, (0.684±0.640) degrees, (0.816±0.767) degrees, (0.912±0.707) degrees in lateral, longitudinal, vertical, pitch, roll and yaw directions. According to the survey analysis, the number of times to practice at home decreased as the treatment went by. An improvement was seen in patients' self-evaluation in mastering DIBH technique with proper coaching program (from 60% to 90%). Patients' anxiety in performing DIBH were alleviated greatly towards the end of the treatment (from 47% to 15%). 100% of the patients were willing to go for DIBH treatment if given a second chance and additional suggestions claimed that professional clinical teams and coaching program were important for their DIBH treatment journey. CONCLUSION: A comprehensive DIBH coaching program can effectively identify SG-DIBH patient's suitability. Patient compliancy, treatment accuracy and treatment experience can be enhanced with good coaching program. The involvement of clinical team from consultation to pre-treatment and treatment stage is essential for a successful SG-DIBH treatment.

Outcomes and Failure Patterns after Chemoradiotherapy for Locally Advanced Rectal Cancer with Positive Lateral Pelvic Lymph Nodes: A Propensity Score-Matched Analysis.

PURPOSE/OBJECTIVE(S): Locally advanced rectal cancer (LARC) combined with positive lateral pelvic lymph nodes (LPLN) tends to present worse prognosis. However, for those patients it remains unclear whether other combination high-risk factors affect the prognosis. This study aimed to use propensity score matching (PSM) to examine long-term outcomes and failure patterns in patients with positive vs. negative LPLN. MATERIALS/METHODS: Patients with LARC were retrospectively divided into LPLN-positive and LPLN-negative groups. LPLN-positivity was defined as lymph node short diameter greater than or equal to 7 mm with specific morphological features. Clinical characteristics were compared between the groups using the chi-square test. PSM was applied to balance these differences. Progression-free survival (PFS) and overall survival (OS), and local-regional recurrence (LRR) and distant metastasis (DM) rates were compared between the groups using the Kaplan-Meier method and log-rank tests. RESULTS: Prior to PSM, a total of 651 LARC patients were included. The LPLN-positive group had higher rates of lower location (53.1% vs. 43.0%, P = 0.025), mesorectal fascia (MRF)-positive (53.9% vs. 35.4%, P<0.001) and extramural venous invasion (EMVI)-positive (51.2% vs. 27.2%, P<0.001) disease than the LPLN-negative group. After PSM, there were 114 patients for each group along with the balanced clinical factors, and both groups had comparable surgery, pathologic complete response (pCR), and ypN stage rates. The median follow-up time was 45.9 months, 3-year OS (88.3% vs. 92.1%, P = 0.276) and LRR (5.7% vs. 2.8%, P = 0.172) rates were comparable between LPLN-positive and LPLN-negative groups. Meanwhile, despite no statistical difference, 3-year PFS (78.8% vs. 85.9%, P = 0.065) and DM (20.4% vs. 13.3%, P = 0.061) rates slightly differed between the groups. Among 10 patients with LRR, seven (70.0%) had lateral pelvic recurrence, among them, five patients were LPLN-positive, and four (80.0%) of these patients did not receive simultaneous integrated boost intensity-modulated radiotherapy (SIB- IMRT).45 patients were diagnosed with DM, 11 (40.7%) LPLN-positive and 3 (17.6%) LPLN-negative patients were diagnosed with oligometastases (P = 0.109). CONCLUSION: Our study shows there is a tendency of worse PFS and DM in LPLN-positive than LPLN-negative patients, for LPLN-positive patients, oligometastases account for a large proportion of all distant metastases.

Evaluating the Utility of Traditional Bowel Dose Constraints when Treating Abdominal and Pelvic Sarcomas with Preoperative Radiation Therapy.

PURPOSE/OBJECTIVE(S): Abdominopelvic soft tissue sarcomas (AP-STS) are selectively treated with preoperative radiation therapy (RT) followed by surgery. Due to their rarity, most bowel dose constraints are extrapolated from dosimetric studies for other abdominal or pelvic malignancies where concurrent chemotherapy is often given in addition to RT. We sought to investigate associations between dosimetric bowel constraints and the risk for developing acute and long-term toxicities in patients who received preoperative RT for AP-STS. MATERIALS/METHODS: We performed a retrospective review of patients treated at a tertiary cancer center for non-metastatic AP-STS between 2005 and 2020. Dosimetric parameters for the "bowel bag" organ at risk structure were extracted for each patient. Chi-Square or Fisher's Exact Test, where appropriate, was utilized to compare the proportion of patients who exceeded constraints to the bowel bag contour as per the consensus RT retroperitoneal sarcoma guidelines, and the development of acute and long-term toxicities. RESULTS: We identified 39 patients with available dosimetric data. The median follow-up was 34 months (IQR 20-47). Approximately half of the tumors were located in the pelvis (n = 20, 51%), and the majority were treated with IMRT/VMAT (n = 35, 90%). 31 patients (80%) presented with de novo disease, and 20% (n = 8) were recurrent presentations but had not received prior RT. The most common histology was leiomyosarcoma (n = 15, 38%), followed by de-differentiated liposarcoma (n = 8, 21%). The median bowel max dose (defined as D0.1cc) was 5309cGy [IQR 5262-5830]. Thirteen patients (33%) exceeded the volumetric V15 Gy <830cm3 bowel bag constraint, and 18 (46%) exceeded the V45 Gy ≤ 195cm3 bowel bag constraint. Overall, 17 patients (44%) had acute grade 1 diarrhea, and 11 (28%) had grade 1-2 nausea. Five patients (13%) had long-term radiation-related toxicities, including 1 patient who developed an enterocutaneous fistula. There was no association between exceeding V15 Gy>830 cm3 (p = 0.31) or V45 Gy≥195cm3 (p = 0.65) bowel bag constraints and developing a long-term RT toxicity. Similarly, exceeding V15 Gy>830 cm3 or V45 Gy≥195cm3 did not lead to increased risks of developing acute diarrhea, nausea, or any other acute RT toxicity (all p>0.05). CONCLUSION: Traditional volumetric bowel bag dose constraints are frequently exceeded given the large size of AP-STS at presentation and thus the large RT target volumes. Despite a significant proportion of patients exceeding these constraints, these data suggest that RT is overall well-tolerated, and the risk of developing toxicities does not correlate with traditional bowel bag volumetric constraints. There are ongoing efforts to substantially expand this cohort for further investigation into the relationship between dosimetric data and bowel toxicities in order to identify more predictive bowel constraints that can be used during treatment planning of AP-STS.

4D-MRI Guided Stereotactic Body Radiation Therapy for Unresectable Colorectal Liver Metastases.

PURPOSE/OBJECTIVE(S): This study evaluated the feasibilities and outcomes following four-dimensional magnetic resonance imaging (4D-MRI) guided stereotactic body radiation therapy (SBRT) for unresectable colorectal liver metastases (CRLM). MATERIALS/METHODS: From March 2018 to January 2022, we identified 76 unresectable CRLM patients with 123 lesions who received 4D-MRI guided SBRT in our institution. 4D-MRI simulation with or without abdominal compression was conducted for all patients. The prescription dose was 50-65 Gy in 5-12 fractions. The image quality of computed tomography (CT) and MRI were compared using the Clarity Score. Clinical outcomes and toxicity profiles were evaluated. RESULTS: The 4D-MRI significantly improved the image quality compared with CT images (mean Clarity Score: 1.67 vs 2.88, P < 0.001). The abdominal compression significantly reduced motions in cranial-caudal direction (P = 0.03) with 2 phase T2 weighted images assessing tumor motion. The median follow-up time was 12.5 months. For 98 lesions assessed for best response, the complete response, partial response and stable disease rate were 57.1 %, 30.6 % and 12.2 %, respectively. The local control (LC) rate at 2 year was 97.3%. 46.1% of patients experienced grade 1-2 toxicities and only 2.6% patients experienced grade 3 hematologic toxicities. CONCLUSION: The 4D-MRI technique allowed precise target delineation and motion tracking in unresectable CRLM patients. High LC rate and mild toxicities were achieved. This study provided evidence for using 4D-MRI guided SBRT as an alternative treatment in unresectable CRLM.

Intraoral Gavage of Second-Generation Probiotic Lactobacillus Reuteri Releasing IFN-ß (LR-IFN-ß) Mitigates Intestinal Irradiation Toxicity and Improves Survival During Whole Abdomen Irradiation (WAI).

PURPOSE/OBJECTIVE(S): We sought to establish a method by which to overcome the toxicity of WAI to facilitate clinical application in Ovarian Cancer patients. MATERIALS/METHODS: We irradiated C57BL/6J mice to 19.75 Gy WAI and assessed the primary endpoint of overall survival (OS). In a separate experiment, mice were irradiated to 12 Gy WAI and intestinal barrier integrity was compared between groups: control (0 Gy), irradiation only, 12 Gy + LR, 12 Gy + IFN-ß, and 12 Gy + LR-IFN-ß. Luminex assay of plasma and intestinal cells were also assayed at day 5 after WAI for radiation-induced inflammatory cytokines, and fecal matter was analyzed for LR-IFN-ß clearance and levels of the LR-derived IFN-ß gene from day 1 to 5 in control non-irradiated mice. Moreover, fluorescent beads were intraorally administered three hours prior to sacrifice at days 2 or 5 after WAI, and blood was assayed for beads. RESULTS: Mice receiving LR-IFN-ß (109 bacteria in 100 mL of saline) 24-hours following a single fraction of 19.75 Gy WAI showed improved OS compared to control irradiated mice (p = 0.03). LR-IFN-ß gavage maintained intestinal barrier integrity (p < 0.05) by stimulating intestinal stem cells regenerations (improved levels of Lgr5+ cells, occludin, and I-CAM; p < 0.05), and reduced levels of intestinal pro-inflammatory cytokines, including IFN-γ (p = 0.0261), IL-3 (p < 0.0020) and IL-17 (p < 0.0070). There was no significant effect of control LR or intraperitoneal injection of IFN-ß protein at 24 hours after WAI. Detectable levels of LR-IFN-ß bacteria were also cleared from fecal matter by day three via colony assay and rt-PCR, with no detectable growth of LR-IFN-ß in blood from gavaged irradiated mice (13.5 Gy WAI). CONCLUSION: LR-IFN-ß is both a feasible and effective radiation mitigator that could potentially improve the management of ovarian cancer patients. Furthermore, the subsequent addition of platinum/taxane-based chemotherapy to the combination of WAI and LR-IFN-ß should reduce tumor volume while protecting the intestine and thus improve overall survival in ovarian cancer patients.

Impact of Race and Socioeconomic Factors on Clinical Outcomes in Cervical and Endometrial Cancer Patients Treated with Brachytherapy.

PURPOSE/OBJECTIVE(S): Racial and socioeconomic disparities impact cancer care and outcomes. This project aimed to evaluate relationship between race and socioeconomic factors and clinical outcomes in patients with cervical and endometrial cancer. MATERIALS/METHODS: All cervical and endometrial cancer patients treated with brachytherapy at our institution from 2007-2017 were identified. Race, insurance status, employment status, disability status, and distance from brachytherapy center were recorded. Clinical characteristics including stage at presentation, number of involved nodes, histology, and brachytherapy technique (cervical cancer only) were recorded. PFS and OS were calculated from date of last brachytherapy fraction, with censorship at date of last follow-up. Correlation was tested between race and socioeconomic factors and PFS and OS using Cox regression models. Association with other outcomes was examined with Wilcoxon rank sum tests, Fisher's exact tests, and Spearman's rank correlation coefficients. RESULTS: A total of 251 cervical and 130 endometrial cancer patients were identified, with median follow-up 5.2 years and 4.8 years, respectively. For cervical cancer, UVA showed significant correlation for PFS and OS with race, insurance status, employment status, and disability status. For endometrial cancer, UVA showed significant correlation for PFS with race, insurance status, and disability status, and for OS with race and insurance status. For cervical cancer, MVA showed significantly improved PFS in patients with insurance (p < 0.001) and patients who were employed (p = 0.002), and significantly improved OS in patients who were white (p = 0.039), patients with insurance (p<0.001), and patients who were employed (p-0.001). For endometrial cancer, MVA showed significantly improved PFS and OS in patients who were white (p = 0.003 and p = 0.005, respectively) and patients with insurance (p = 0.027 and p = 0.002, respectively). For cervical cancer, there was no correlation between insurance or employment status and stage. For endometrial cancer, there was no correlation between race or insurance status and stage. CONCLUSION: For cervical cancer, insurance and employment status are significant predictors of PFS and OS, and race is additionally a significant predictor of OS. For endometrial cancer, race and insurance status are significant predictors of PFS and OS.

Fractionated Stereotactic Radiotherapy in the Management of Dural Recurrence of Olfactory Neuroblastoma.

PURPOSE/OBJECTIVE(S): Treatment protocols for dural recurrence among esthesioneuroblastoma patients have not been standardized. We assess the outcomes of fractionated stereotactic radiotherapy (FSR) for patients with olfactory neuroblastoma (ONB) dura-based recurrences. MATERIALS/METHODS: We identified ONB patients with dura-based recurrences treated with FSR after prior radiotherapy who were enrolled between 2013 and 2022 in our prospective head and neck reirradiation and skull base registries. In-field tumor control (within 2 cm of prescribed radiotherapy volume) and out-of-field tumor control (non-contiguous or contralateral dura, nodal, or distant metastases) were analyzed. RESULTS: Thirteen patients with 28 dural lesions were included in this analysis. All patients were initially treated with surgery to their primary paranasal sinus disease; 69% with a craniofacial approach followed by adjuvant radiotherapy to a median dose of 63 Gy (range 60-72.4 Gy) prescribed to the resected tumor bed. Patients re-presented with dural recurrence at median 58.3 months (range 35.0 - 163.0 months) from completion of their initial treatment. Two patients underwent dural resections. On presentation of recurrence, 4 patients had 1 lesion treated, with a median of 2 lesions treated (range 1-4 lesions). All dural based tumors were treated with FSR to a median dose of 27 Gy in 3 fractions delivered QOD. 68Ga-DOTATATE PET/CT was utilized for FSR treatment planning in 31% of cases. The median follow up from FSR was 23.3 months (range: 13.1 - 51.6 months). The 1-year overall survival and progression free survival was 75% and 38%, respectively. The 1- and 2-year in-field control rate was 85% and 75%, respectively. Among treated lesions, 25 of 28 (89%) responded or remained stable following FSR. Two patients (3 lesions) had evidence of in-field radiographic progression at 17 and 9 months, respectively. Five patients (38%) experienced progression in the contralateral or non-contiguous dura, and 5 patients (38%) developed distant metastases. The overall out-of-field progression rate was 58% at 1 year. There was no grade 3 or higher toxicity observed. Three patients (23%) developed asymptomatic changes on MRI consistent with brain necrosis, all of which occurred in a previously irradiated region. CONCLUSION: In the largest single institution study of FSR reirradiation for ONB dural recurrence to date, high local control rates with minimal toxicity are attainable. However, subsequent out-of-field dural recurrences and/or distant metastases remain problematic.

Distribution Pattern of Metastatic Lymph Nodes in 870 Cases of Nasopharyngeal Carcinoma: A Clue for Individualized Elective Prophylactic Neck Irradiation.

PURPOSE/OBJECTIVE(S): We aimed to explore a potential individualized elective prophylactic neck irradiation (iEPNI) to optimize the current strategy by investigating the distribution of metastatic lymph nodes (LNs) in nasopharyngeal carcinoma (NPC). MATERIALS/METHODS: Magnetic resonance imaging (MRI) and clinical data of 870 non-distant metastatic NPC patients admitted to the Hunan Cancer Hospital between January 2019 and December 2019 were reviewed. All patients were staged using the 8th TNM staging system, and the LNs location was assigned based on the 2013 guidelines. According to the distribution patterns of the LNs in NPC, the intra-regional lymphatic drainage levels were categorized into the following three stations: Station 1st of level VIIa and II; Station 2nd of level III and Va; and Station 3rd of level IV, Vb, and Vc. Other levels were defined as extra-regional areas. RESULTS: The incidence of LNs metastasis was 822/870 (94.5%), including 198 cases of unilateral metastasis and 624 cases of bilateral metastasis. Among the 870 patients, the most frequently involved intra-regional lymphatic drainage was level IIb (87.1%), followed by level VIIa (80.0%), IIa (61.8%), Va (30.6%), IV (21.4%), Vb (8.9%), and Vc (1.1%). In the extra-regional areas, the detailed LNs distribution was: level Ia (0.2%), level Ib (7.7%), level VI (0.1%), level VIIb (5.6%), level VIII (5.5%), level IX (0.3%), and level X (0.2%). The rates of LNs metastasis in Station 1st, Station 2nd, and Station 3rd were 820/870 (94.3%), 532/870 (61.1%), and 199/870 (22.9%), respectively. Only 4 patients were considered to be skipping metastasis among the three stations (4/870, 0.5%). Additionally, in 203 patients with unilateral Station 1st LNs metastasis, there were 86 (42.4%) and 37 (18.2%) patients with ipsilateral Station 2nd and Station 3rd metastasis, respectively, and 3 (1.5%) and 1 (0.5%) patients with contralateral Station 2nd and Station 3rd LNs metastasis, respectively. CONCLUSION: LNs spread from Station 1st to Station 3rd successively with rare skipping metastasis. A potential iEPNI strategy of prophylactical neck irradiation to the ipsilateral latter node-negative station might be feasible, which is detailed as follows: irradiation to Station 1st in patients with no LNs metastasis, irradiation to Station 2nd in patients with only Station 1st metastasis, and irradiation to Station 3rd in patients with Station 2nd metastasis but without Station 3rd metastasis. Further prospective investigations are expected to validate the strategy.

Occult Lymph Node Metastasis in cN0 Tongue Squamous Cell Carcinoma: A Prospective Observational Study.

PURPOSE/OBJECTIVE(S): Tongue squamous cell carcinoma (TSCC) is prone to occult lymph node metastasis, and preoperative evaluation of cervical nodes is critical for determining treatment strategies. There is scarce report of detecting occult lymph node metastasis in TSCC by using multi-parameter magnetic resonance imaging (mpMRI), spectral computed tomography (spectral CT) or other diagnostic functional imaging. In this study, we aimed to analyze the incidence and risk factors of occult lymph node metastasis in cN0 TSCC by comparing preoperative imaging with postoperative pathology results. MATERIALS/METHODS: This study prospectively enrolled newly-diagnosed cN0 TSCC patients admitted to the Hunan Cancer Hospital between May, 2022 and December, 2022. All patients underwent primary resection and selective dissection of cervical lymph nodes. MpMRI and spectral CT scan of oral cavity and neck were performed prior to surgery. Preoperative evaluation of lymph node metastasis was conducted by two senior radiologists independently. The location of cervical lymph nodes was assigned based on the 2013 consensus guidelines. RESULTS: A total of 26 cN0 TSCC patients (6 cT1 stage, 13 cT2 stage, and 7 cT3 stage) were enrolled. The median age was 53 (range, 36-64), and there were 25 males. Among all patients, 13 patients underwent unilateral cervical lymph node dissection, while 13 patients underwent bilateral cervical lymph node dissection. A total of 208 lymphatic drainage areas were resected, and 1003 lymph nodes were removed. There were 7 of pT1, 12 of pT2, 7 of pT3 based on postoperative pathological stages. Besides, there are 21 cases staged pN0, 2 cases staged pN1, 2 cases staged pN2, and 1 case staged pN3. Among the 26 patients, 5 (19.23%) cases had occult lymph node metastasis. A total of 8 metastatic lymph nodes (4 in ipsilateral Ib level, 1 in contralateral Ib level, 3 in IIa level ipsilateral side) were detected in the whole group. No lymph node metastasis was detected in level IIb, III and IV. The median maximum diameter of metastatic lymph nodes was 12 mm (range 5 to 15 mm), and 1 extra-nodal extension was observed. Moreover, all occult lymph node metastases occurred in patients with a primary invasion depth of ≥ 5 mm (29.41%, 5/17). CONCLUSION: The incidence of occult lymph node metastasis in cN0 TSCC remains high under functional imaging diagnostic technology. Preventive neck dissection is necessary for patients with cN0 disease, especially those with primary tumor invasion depth exceeding 5 mm.

Tumor Treatment Response Assessed During the Concurrent Chemoradiotherapy for Nasopharyngeal Patients.

PURPOSE/OBJECTIVE(S): To evaluate intratumoral treatment response distribution with using FDG-PET/CT during the chemoradiotherapy of nasopharyngeal patients (NPC). MATERIALS/METHODS: A total of 5 of 30 patients with stage III-IVA NPC were enrolled in the institutional protocol for induction/concurrent chemoradiotherapy with radiation dose of 70 Gy in 33 fractions. For each patient, a pre-radiation treatment FDG-PET/MRI image (SUV0) and a mid-treatment image (SUVm) at the treatment dose of 31.8 Gy were obtained. Followed by deformable PET/MRI registration between SUV0 and SUVm, the tumor voxel SUV reduction ratio was obtained to construct a tumor dose response matrix (DRM). Tumor SUVavid was also constructed by limiting tumor voxel SUVm > a given value. Spatial correlations of the tumor SUV0, SUVm, SUVavid and DRM were determined. RESULTS: The mean and coefficient variation (CV) of the SUV0, SUVm and DRM for all tumors were 5.05 (52%), 2.72 (49%) and 0.64 (63%) (Table contains the individual data), which were smaller than those on the SUVs of head-n-neck HPV+ patients reported previously due to the induction chemotherapy, but had much larger DRM mean and CV. The inter-tumoral CVs of SUV0 and DRM were 29% and 27%, which were much lower than those of the intra-tumoral CVs 43% and 57%. Meanwhile, the intra-tumoral variations on SUV0 was smaller than the one of head-neck HPV+ patients, but the DRM intra-variation was much larger. There was a weak correlation between SUV0 and SUVm with the correlation coefficient 0.13, a medium correlation of -0.55 between SUV0 and DRM, but a strong correlation, 0.72, between SUVm and DRM. However, the spatial correlation between tumor DRM and SUVavid was getting weaker as the SUVavid value increasing and equal 0.47 with SUVavid value > 3. CONCLUSION: The spatial dose response DRM for NPC in the concurrent chemoradiotherapy was relatively high, while had relatively low baseline tumor metabolic activity SUV0. It was most likely due to the induction chemotherapy. In addition, the tumor dose response showed vary large intra-tumoral variation. The high correlations between DRM and SUVm imply that SUVavid could be used partially to guide adaptive modification of NPC treatment with carefully selected boundary value.

Tumor Treatment Response Assessed During the Chemo-Radiotherapy for Locally Advanced NSCLC.

PURPOSE/OBJECTIVE(S): To evaluate the capability of assessing intratumoral treatment response distribution with using FDG-PET/CT during the chemoradiotherapy of locally advanced NSCLC. MATERIALS/METHODS: Twelve of total 50 patients with stage III NSCLC were enrolled in the institutional protocol for concurrent chemoradiotherapy with treatment dose of 54-60 Gy in 27-30 fractions. For each patient, a pre-treatment FDG-PET/CT image (SUV0) and a mid-treatment image (SUVm) obtained within the treatment dose of 24 ∼ 46 Gy were obtained. Followed by deformable PET/CT registration between SUV0 and SUVm, the tumor voxel SUV reduction ratio was obtained to construct a tumor dose response matrix (DRM). Tumor SUVavid was also constructed by limiting tumor voxel SUVm > a given value. Spatial correlations of the tumor SUV0, SUVm, SUVavid and DRM were determined. RESULTS: The mean and coefficient variation (CV) of the SUV0, SUVm and DRM for all tumors were 6.56(64%), 2.82(59%) and 0.52(70%) (Table contains the individual data), which were like those on the SUVs and the mean DRM of head-neck HPV- patients reported previously, but much larger on the DRM variation. The inter-tumoral CVs of SUV0 and DRM were 17% and 43%, which were much smaller than those of the intra-tumoral CVs 61% and 55%. Meanwhile, the intra-tumoral variations on both SUV0 and DRM were much larger than those of head-neck HPV- patients. There was a weak correlation between SUV0 and SUVm with the correlation coefficient 0.32, a medium correlation of -0.51 between SUV0 and DRM; 0.58 between SUVm and DRM. It implies that the rule of tumor dose response DRM on treatment modification decision cannot be fully replaced by either SUV0 or SUVm. The spatial correlation between tumor DRM and SUVavid was 0.23 with SUVavid value > 3, which was getting weaker when increasing SUVavid value. CONCLUSION: Spatial dose response for NSCLC assessed using FDG-PET/CT feedback demonstrated high treatment resistant patterns, which had a large intra-tumoral variation. In addition, the medium correlations of DRM vs SUV0 and DRM vs SUVm imply that all these factors could be used to guide adaptive modification of NSCLC treatment.

Application of the Integrated Deep Reinforcement Learning Solution in Automatic IMRT Planning for Gastric Cancer.

PURPOSE/OBJECTIVE(S): The intensity-modulated radiation therapy (IMRT) treatment planning optimization process is usually a manual, tedious and time-consuming task. An unsupervised integrated automatic IMRT planning solution was discussed and implemented to simulate the manual operation during the whole planning process. MATERIALS/METHODS: Based on knowledge-based planning (KBP) and deep reinforcement learning (DRL) schemes, a novel integrated solution combining the multi-objectives optimization policy network (MOPN) and three-dimensional dose prediction module (3D-DPM) was proposed. The MOPN was trained to learn how to adjust multiple optimization objectives in commercial Eclipse treatment planning system (TPS). The 3D-DPM was developed to generate the patient-specific initial optimization objectives to reduce the overall exploration space during MOPN training. The Eclipse 15.6 TPS Scripting Application Programming Interface (ESAPI) was used to realize the automatic interaction between models and TPS. In this study, 100 previously treated gastric cancer cases were selected from the clinical database, 70 cases were used for the training of dose prediction model and MOPN, the remaining 30 cases for evaluating the feasibility and effectiveness of automatic treatment planning solution. RESULTS: For all tested cases, the complete automatic treatment plan for a new case was generated based on the integrated solution, with about 6 min. Compared with the MOPN initial plans, the actual dose of spinal cord, liver, kidney-left, kidney-right, and intestine in the MOPN final plans reduced 42.4%, 25.2%, 52.4%, 37.8%, 11.8% respectively. The dose result of OARs in the MOPN final plans was similar to those in the clinical plans. In addition, a new case was able to complete optimization with about 15 adjustment steps by the trained MOPN. CONCLUSION: We successfully developed an integrated solution for automatic treatment planning. It first includes the dose prediction module for obtaining patient-specific initial optimization objectives. We demonstrated that the trained MOPN can mimic the operations of the physicians to adjust multiple objectives and obtain a high-quality plan in a shorter time. This integrated solution contributes to improving the efficiency of the overall planning workflow and reducing the variation of plan quality in clinical practice. Although improvement is warranted, the proposed integrated solution is a promising practical and effective approach for automatic planning in commercial TPS.

Proton Based Stereotactic Radiotherapy for Skull Base Patients: Dosimetric Comparison to 4 Modern Radiation Treatment Modalities.

PURPOSE/OBJECTIVE(S): Re-irradiation with ablative doses to a smaller target volume and strict critical structure constraint is a challenge for modern radiation planning and delivery systems. Several advanced radiation treatment techniques can be used for fractionated stereotactic ablative radiosurgery (FSRS) in select patients with unresectable recurrent head and neck tumors. In this study, in order to better understand the dosimetry advantage of each technique, we compare the stereotactic treatment plans of our new small spot size Hitachi proton treatment unit to those of CyberKnife stereotactic radiosurgery (CK), Gamma Knife radiosurgery (GK), volumetric modulated arc therapy (VMAT), and MR Linac radiotherapy (MRL). MATERIALS/METHODS: Ten FSRS skull base patients treated at our institution using VMAT (n = 5) or GK (n = 5) techniques. Intensity-modulated proton therapy (IMPT) plans were created in Raystation using Monte Carlo dose calculation algorithm. VMAT, CK, GK and MRL plans were generated in RayStation, Accuray Precision, Leksell Gamma Plan, and Monaco treatment planning systems, separately. Planning goals were to achieve the best target coverage of prescribed dose without compromising the critical organs at risk dose volume constraints of the clinical treatment plans. Plans were compared based on percent CTV coverage, Paddick conformity index (PCI), gradient index (GI, V50/V100), dose homogeneity index (HI, (D2-D98)/D50), low dose bath volume (LDBV, ratio of total volume irradiated between 20% and 50% prescription dose and the target volume), beam-on-time (BOT), and mean/maximum doses to brainstems. RESULTS: The median target volume was 15.5 cm3 (range 1.0 - 36.23 cm3). The prescription was 45 Gy in 5 fractions for VMAT patients, and 21 - 27 Gy in 3 fractions for GK patients. The comparison of the treatment plans of these 5 delivery modalities was shown in table. All techniques achieved comparable CTV coverage. GI was superior for GK plans and outstanding in CK and IMPT plans. IMPT plans were also outstanding in regard to BOT and PCI. Significantly improved HI, LDBV and brainstem mean doses were achieved in IMPT plans. For adjacent brainstem and other OARs, maximum doses were comparable among all techniques. CONCLUSION: In these five advanced radiation therapy modalities, proton therapy SBRT showed dosimetric advantage over other modalities to spare nearby OARs without sacrifice of target coverage. Further studies are needed to utilize this clinical benefit and investigate plan robustness.

Proton Therapy for Ocular Melanoma: A Dosimetric Comparison of Three Different Delivery Systems.

PURPOSE/OBJECTIVE(S): The purpose of this study is to compare the treatment plans for intraocular tumors with two types of Pencil Beam Scanning (PBS) machine configurations and compare them with the widely used uniform scanning (US)/scattering technique. MATERIALS/METHODS: Two virtual PBS machines were constructed for ocular planning. The first machine (P1) consisted of a standard spot size and a 7.5cm WET range shifter (RS) positioned 50cm upstream from the aperture. The second machine (P2) had a smaller spot size and used a 4cm WET RS but had no aperture support. These PBS delivery systems resemble currently available models. Ten patients with different locations and sizes of intraocular tumors were planned with US using 2-3 conformal fields following our institution's intraocular criteria. PBS spot patterns for each machine were optimized using the same beam geometry as the US plan to achieve identical tumor coverage. PBS distribution was calculated using Monte Carlo. All air gaps were minimized as small as clinically achievable. PBS plans passed robustness criteria with all scenarios meeting CTV D95>95% with 2mm translational offsets and 3.5% range uncertainty. RESULTS: The average conformity index (CI) of 95% reference isodose was better for both PBS techniques (P1: 1.43±0.22, P2:1.5±0.32) versus US (1.72±0.56) for all plans (p = 0.025, p = 0.034). The average CI of 50% reference isodose was worse for the P2 plans (10.4±3.3) compared to US (9.34±2.93). However, CI 50% for P1 plans was better than US (5.21±1.24, p<0.003). There were no significant improvements to OARs using P2. However, the mean dose to anterior structures ciliary body, lacrimal gland, and D0.03cc lens were significantly lower in the P1 plans than in the US plans (p<0.016). CONCLUSION: Small spot size PBS systems without apertures can achieve similar coverage to US plans but have higher OAR dose. PBS systems with a standard spot size and reconfigured RS and apertures are better for anterior OAR sparing and is non-inferior to US planning of intraocular targets.