Investigation of the distribution of inguinal lymph nodes and delineation of the inguinal clinical target volume using 18F-FDG PET/CT.

OBJECTIVE: Radiotherapy is a crucial treatment modality for pelvic cancers, but uncertainties persist in defining the clinical target volume (CTV) for the inguinal lymphatic drainage region. Suboptimal CTV delineation may compromise treatment efficacy and result in subpar disease control. This study aimed to investigate and map the distribution of lymph node metastases (LNM) in the groin area to facilitate an improved and detailed CTV definition using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). METHODS: Inguinal LNM in patients with biopsy-proven pelvic malignancies were identified using 18F-FDG PET/CT scan. The longitudinally nearest axial plane was determined based on six typical bony landmarks, and the axial direction relative to the femoral artery of LNM was recorded. The distances from the LNM to the nearest edge of the femoral artery were measured on the axial plane. An optimal margin to cover 95% of LNM was estimated to develop contouring recommendations. RESULTS: In this study, 500 positive LNM were identified by 18F-FDG PET/CT among 185 patients with primary pelvic malignancies. Relative to the femoral artery, lymph nodes were distributed laterally (10:00-11:00, n = 35), anteriorly (12:00-1:00, n = 213), and medially (2:00-4: 00, n = 252). For CTV delineation, the recommended distances from the femoral artery on the SFH were lateral 19 mm, anterior 19 mm, and medial 25 mm; on the SGT were lateral 26 mm, anterior 20 mm, and medial 25 mm; on the SPS were lateral 28 mm, anterior 29 mm, and medial 26 mm; on the IPS were anterior 29 mm and medial 28 mm; on the IIT were anterior 27 mm and medial 27 mm; on the ILT were anterior 25 mm and medial 23 mm. Use interpolation to contour the area between six axial slices, including any radiographically suspicious LNM. CONCLUSIONS: Using 18F-FDG PET/CT, we investigated the distribution pattern of inguinal LNM and propose a more comprehensive guideline for inguinal CTV delineation.

Recurrence pattern of glioblastoma treated with intensity-modulated radiation therapy versus three-dimensional conformal radiation therapy.

PURPOSE: To evaluate recurrence patterns of and survival outcomes in glioblastoma treated with intensity-modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3D-CRT). MATERIALS AND METHODS: We retrospectively examined 91 patients with glioblastoma treated with either IMRT (n = 60) or 3D-CRT (n = 31) between January 2013 and December 2019. Magnetic resonance imaging showing tumor recurrence and planning computed tomography scans were fused for analyzing recurrence patterns categorized as in-field, marginal, and out-of-field based on their relation to the initial radiation field. RESULTS: The median overall survival (OS) was 18.9 months, with no significant difference between the groups. The median progression-free survival (PFS) was 9.4 months, with no significant difference between the groups. Patients who underwent gross total resection (GTR) had higher OS and PFS than those who underwent less extensive surgery. Among 78 relapse cases, 67 were of in-field; 5, marginal; and 19, out-of-field recurrence. Among 3D-CRT-treated cases, 24 were of in-field; 1, marginal; and 9, out-of-field recurrence. Among IMRT-treated cases, 43 were of in-field; 4, marginal; and 10, out-of-field recurrence. In partial tumor removal or biopsy cases, out-of-field recurrence was less frequent in the IMRT (16.2%) than in the 3D-CRT (36.3%) group, with marginal significance (p = 0.079). CONCLUSION: IMRT and 3D-CRT effectively managed glioblastoma with no significant differences in OS and PFS. The survival benefit with GTR underscored the importance of maximal surgical resection. The reduced rate of out-of-field recurrence in IMRT-treated patients with partial resection highlights its potential utility in cases with unfeasible complete tumor removal.

A Four-dimensional Computed Tomography Generated Internal Target Volume Approach to Paediatric High Risk Neuroblastoma to Reduce Organ at Risk and Normal Tissue Irradiation.

AIMS: The magnitude of upper abdominal organ motion in children may be overestimated by current planning target volumes (PTV). A four-dimensional computed tomography (4DCT) - derived internal target volume (ITV) is frequently used in adult radiotherapy to take respiratory-related organ motion into account. In this study, the dosimetric consequences for target coverage and organs at risk from the use of an ITV approach compared to standard PTV margins in children with high-risk neuroblastoma were investigated. MATERIALS AND METHODS: 14 patients, median age 4.1 years, range 1.5 - 18.9 years, (9 midline targets, 5 lateralised) each had two dual arc volumetric modulated arc therapy (VMAT) plans (14 ×1.5 Gy) generated. One used an ITV-approach; motion information derived from 4DCT (PTV_itv) with a 5mm ITV to PTV expansion, and the other a PTV margin of 10mm from CTV to PTV (PTV_standard). Differences in absolute PTV volume and organ at risk doses are described. RESULTS: The ITV approach resulted in a highly significant reduction in PTV size of 38% (p<0.0001). For midline targets, an ITV approach resulted in a small but statistically significant reduction in combined mean kidney dose of 0.8Gy, p 0.01. Mean heart and lung dose were reduced by an average of 1 Gy with an ITV approach. Non-PTV integral dose from 30.4 Gy L to 27.8 Gy L using an ITV approach. CONCLUSION: An ITV-approach to respiratory related organ motion management in children can significantly reduce absolute PTV volumes, maintain target coverage and reduce dose delivered to normal tissue in proximity to the target. This is an essential step to maximising the benefits of highly conformal radiotherapy techniques including VMAT for this patient group, and in the future with Proton Therapy.

Evaluating the Effectiveness of Proton Beam Therapy Compared to Conventional Radiotherapy in Non-Metastatic Rectal Cancer: A Systematic Review of Clinical Outcomes.

Background and Objectives: Conventional radiotherapies used in the current management of rectal cancer commonly cause iatrogenic radiotoxicity. Proton beam therapy has emerged as an alternative to conventional radiotherapy with the aim of improving tumour control and reducing off-set radiation exposure to surrounding tissue. However, the real-world treatment and oncological outcomes associated with the use of proton beam therapy in rectal cancer remain poorly characterised. This systematic review seeks to evaluate the radiation dosages and safety of proton beam therapy compared to conventional radiotherapy in patients with non-metastatic rectal cancer. Materials and Methods: A computer-assisted search was performed on the Medline, Embase and Cochrane Central databases. Studies that evaluated the adverse effects and oncological outcomes of proton beam therapy and conventional radiotherapy in adult patients with non-metastatic rectal cancer were included. Results: Eight studies were included in this review. There was insufficient evidence to determine the adverse treatment outcomes of proton beam therapy versus conventional radiotherapy. No current studies assessed radiotoxicities nor oncological outcomes. Pooled dosimetric comparisons between proton beam therapy and various conventional radiotherapies were associated with reduced radiation exposure to the pelvis, bowel and bladder. Conclusions: This systematic review demonstrates a significant paucity of evidence in the current literature surrounding adverse effects and oncological outcomes related to proton beam therapy compared to conventional radiotherapy for non-metastatic rectal cancer. Pooled analyses of dosimetric studies highlight greater predicted radiation-sparing effects with proton beam therapy in this setting. This evidence, however, is based on evidence at a moderate risk of bias and clinical heterogeneity. Overall, more robust, prospective clinical trials are required.

Early recurrence as a pivotal event in nasopharyngeal carcinoma: identifying predictors and key molecular signals for survivors.

PURPOSE: The duration of response to treatment is a significant prognostic indicator, with early recurrence (ER) often predicting poorer survival outcomes in nasopharyngeal carcinoma (NPC) survivors. This study seeks to elucidate the factors contributing to the onset of ER following radiotherapy in NPC survivors. METHODS: This investigation encompassed 2,789 newly diagnosed NPC patients who underwent radical intensity-modulated radiotherapy. Ordinal logistic regression analysis was employed to evaluate the independent predictors of earlier recurrence. A machine learning-based prediction model of NPC recurrence patterns was developed. Tumorous RNA-sequencing (in-house cohort: N = 192) and biological tipping point analysis were utilized to infer potential molecular mechanisms associated with ER. RESULTS: Our results demonstrated that ER within 24 months post-initial treatment was the optimal time frame for identifying early malignant progression in NPC survivors. The ER cohort (150 of 2,789, 5.38%) exhibited a notably short median overall survival of 48.6 months. Multivariate analyses revealed that male gender, T4 stage, local or regional residual disease, detectable pre- and post-radiotherapy EBV DNA, and the absence of induction chemotherapy were significant predictors of earlier recurrence. The machine learning-based predictive model further underscored the importance of tumor-related factors in NPC recurrence. Moreover, ER emerged as a pivotal stage in NPC progression, with 15 critical transition signals identified potentially associated with the negative modulation of the immune response. CONCLUSIONS: Our comprehensive analysis of NPC recurrence patterns has unveiled insights into the key factors driving ER and provided novel insights into potential early warning biomarkers and the mechanisms underlying NPC progression.

Clinical significance of intensity-modulated radiotherapy (IMRT) to the distant metastatic lymph nodes for metastatic cervical cancer.

OBJECTIVE: To retrospectively explore the clinical significance of radiotherapy to the distant metastatic lymph nodes (cervical/ clavicular/ mediastinal et al.) in metastatic cervical cancer. Hereinto, these cervicothoracic lymph nodes were metastasized from IB1-IVA (initial stage at first treatment), and IVB initially had metastatic disease in these areas at diagnosis. METHODS: Metastatic cervical cancer only with the distant cervicothoracic metastatic lymph nodes (cervical/ clavicular/ mediastinal et al.), without distant parenchymal organs metastasis such as lung, liver, bone, and peritoneum, were enrolled in the analysis. These patients were classified into IB1-IVA and IVB based on their initial stage of first treatment. All patients received IMRT for the distant metastatic lymph nodes. The progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method. RESULTS: Overall, the median PFS was 9 months, and the median OS was 27 months. The subgroup analysis showed that for IB1-IVA, the median PFS was 11 months, and the median OS was 30.5 months. For IVB, the median PFS was 8 months, and the median OS was 16 months. CONCLUSION: Radiotherapy is beneficial to the distant metastatic lymph nodes (cervical/ clavicular/ mediastinal et al.), and could effectively bring the longer PFS and OS for metastatic cervical cancer.

Comparative effectiveness and cost-effectiveness of endoscopic nasopharyngectomy versus intensity-modulated radiotherapy in the treatment of recurrent nasopharyngeal carcinoma: A microsimulation analysis.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a significant health concern in southern China, like Guangdong and Hong Kong. This study aims to predict the effectiveness and cost-effectiveness of two prevalent NPC treatments, intensity-modulated radiotherapy (IMRT) and endoscopic nasopharyngectomy (ENPG). METHODS: A microsimulation model was developed to project the long-term outcomes of IMRT and ENPG, simulating 5000 patients with hypothetical locally recurrent NPC for each treatment option. The tumors of patients confined to the nasopharyngeal cavity, the post-naris or nasal septum, the superficial parapharyngeal space, or the base wall of the sphenoid sinus. Analyses were performed from the healthcare system perspectives of Mainland China and the healthcare provider perspective of Hong Kong, with input parameters sourced from the existing literature and databases. The robustness of findings was evaluated through one-way and probabilistic sensitivity analyses. RESULTS: For DFS, ENPG showed a 29% reduction in risk with an HR of 0.71 (95% CI: 0.64-0.77) compared to IMRT. ENPG demonstrated a significant survival benefit in OS with an HR of 0.59 (95% CI: 0.54-0.65), equating to a 41% reduction in mortality risk. In Hong Kong, IMRT and ENPG yielded QALY gains of 4.59 and 6.29, respectively, with ENPG exhibiting an incremental cost-effectiveness ratio (ICUR) of USD 13 057 per QALY. For Mainland China, ENPG denominated the IMRT and the ICUR was USD -1450 QALY. Probabilistic sensitivity analysis showed a 100% probability of ENPG being cost-effective at the willingness-to-pay thresholds of USD 130 490 per QALY in Hong Kong and USD 12 741 per QALY in Mainland China. CONCLUSION: The analysis confirms that ENPG is more effective and cost-effective than IMRT for treating recurrent NPC in both Hong Kong and Mainland China.

Impact of the radiotherapy rhythm on prognosis in nasopharyngeal carcinoma.

OBJECTIVE: The role of chronoradiobiology in nasopharyngeal carcinoma (NPC) has not been fully elucidated. We sought to investigate the impact of radiotherapy rhythm on the survival outcomes of individuals to explore a chronomodulated radiation strategy to improve prognosis of NPC. METHODS: A cohort comprising non-metastatic NPC patients subjected to intensity-modulated radiotherapy at Fujian Cancer Hospital between Jan. 2016 and Dec. 2019 was assembled. Rhythmic fluctuation of radiotherapy (RFRT) was quantified based on the temporal distribution of radiation delivery. Cox proportional hazard model was performed to explore the impact of radiotherapy rhythm on all-cause mortality. The maximally selected rank statistics method was employed to discern an optimal cutoff. Sensitivity analyses were conducted to ensure the robustness of observed associations. RESULTS: Our analysis encompassed 2245 patients, with a median follow-up duration of 55 months, during which 315 individuals succumbed. Multivariate Cox regression analysis unveiled a significant correlation between prolonged RFRT and heightened mortality risk in NPC patients (HR, 1.17, 95% CI, 1.07-1.27, p < .001), a relationship robust to comprehensive adjustment for confounding variables. A cutoff value of 3 h was selected for potential clinical application, beyond which patients exhibited markedly poorer survival outcomes. Subgroup analyses consistently underscored the directional consistency of observed effects. CONCLUSION: Our study sheds light on the potential advantages of scheduling radiotherapy sessions at consistent times. These findings have implications for optimizing radiotherapy schedules and warrant further investigation into personalized chronotherapy approaches in NPC management.

A Comprehensive Narrative Review of the Impact of Pelvic Radiotherapy on Pelvic Bone Health: Pathophysiology, Early Diagnosis, and Prevention Strategies.

Radiotherapy is a commonly used modality in pelvic malignancies such as prostate, gastrointestinal, or gynecological, either as a primary treatment or an adjuvant post-surgery. Despite its positive impact on the prognosis of these patients, it was found in several studies that it contributes to insufficiency fractures in different sites of the pelvis, more commonly in the sacral ala. This is particularly true for elderly patients. There are several hypotheses on how radiotherapy affects bone health, as it destroys the bone matrix and causes obliterative vasculitis. Several imaging techniques, particularly magnetic resonance imaging (MRI), help detect the radiotherapy-induced fracture and distinguish it from metastases. Some modalities, such as intensity-modulated radiotherapy (IMRT) and brachytherapy, have decreased fracture risk by escaping the adjacent structures to the targeted organ. Pharmacological interventions such as amifostine and desferrioxamine are promising in terms of bone protection, which necessitates further studies to confirm their mechanism of action.

The prognostic implications of radiologic extranodal extension in the lymph nodes of patients with nasopharyngeal cancer.

Objective: This study was developed to explore the prognostic relevance of radiologic extranodal extension (rENE) in lymph node-positive nasopharyngeal carcinoma (NPC) patients. Materials and methods: A retrospective review of data from 249 eligible patients with NPC was performed, with magnetic resonance imaging scans being used for rENE grading. The prognostic value of rENE was assessed through univariate and multivariate analyses. Results: Log-rank tests revealed significant differences between patients with and without rENE in terms of overall survival, progression-free survival (PFS) and distant metastasis-free survival (DMFS). G2 and G3 patients tended to exhibit worse PFS and DMFS relative to G0/G1 patients (p < 0.05). Long-term chemotherapy cycles were associated with significant improvements in the PFS and DMFS of G2 and G3 patients. Conclusion: These results suggest that higher rENE grades (G2/G3) are independently associated with worse survival outcomes among NPC patients, with more aggressive treatment strategies potentially affording greater prognostic benefits to these individuals.

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Current state, challenges, and future perspective of adaptive radiotherapy: A narrative review of nasopharyngeal carcinoma.

Patients with nasopharyngeal carcinoma often experience weight loss and tumor regression during the course of radiotherapy that lasts for up to 6-7 weeks. Adaptive radiotherapy is a systematic feedback control approach based on image-guided technology that adjusts these changes and optimizes the radiotherapy plans according to new imaging findings during treatment. There is growing evidence that adaptive radiotherapy can reduce side effects, improve the quality of life, and enhance disease control. However, the routine application of adaptive radiotherapy for nasopharyngeal remains relatively limited. This review discusses the necessity, clinical benefits, and limitations of adaptive radiotherapy, and presents the current state, challenges, and future perspective of adaptive radiotherapy strategies for nasopharyngeal carcinoma.

Effect analysis of 847 nasopharyngeal carcinoma cases treated with intensity modulated radiation: Experience and suggestions.

OBJECTIVES: To identify the failure patterns and prognostic factors of nonmetastatic nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era. METHODS: Data on 847 patients with newly diagnosed, non-disseminated NPC treated by IMRT between 2012 and 2016 were retrospectively reviewed. Survival outcome, failure patterns and prognosis factors were analyzed. RESULTS: The 5-year local relapse-free survival, nodal relapse-free survival, distant metastasis-free survival, disease-free survival, and overall survival rates were 94.3%, 95.3%, 84.8%, 76.5% and 85.7%, respectively. The major local recurrence sites were the nasopharynx (91.5%, 43/47) and skull base (68.1%, 32/47); 39 patients had in-field failures, four had marginal failures, and four had out-field failures. Level IIb (62.2%, 23/37) was the most frequent regional recurrence site, followed by IIa (35.1%, 13/37) and retropharyngeal region (32.4%, 12/37); 35 cases had in-field failure alone, one had out-field failure alone, and one had both in- and out-field failure. TNM stage was the most significant factor for prognosis prediction. 402 (47.5%) patients had acute adverse events of grade 3 or 4; leukopenia (31.5%) and mucositis (26.7%) was the most common hematological and non-hematological event, respectively. Late complications were slight or moderate damages; xerostomia (647/847, 76.4%) and hearing impairment (422/847, 49.8%) remained the most troublesome. CONCLUSION: NPC patients treated with IMRT obtained satisfactory survival outcomes. The key failure pattern was distant metastasis. The main pattern of local-regional failure was in-field failure. Screening high risk patients with distant metastases and optimizing radiotherapy targets should be studied.

Radiotherapy with S-1 for the treatment of esophageal squamous cell carcinoma 75 years or older.

OBJECTIVE: Explore the efficacy and safety of involved-field irradiation (IFI) combined with S-1 as definitive concurrent chemoradiotherapy (dCRT) for locally advanced elderly esophageal squamous cell carcinoma (ESCC), under the premise of intensity-modulated radiotherapy (IMRT). METHODS: We designed a prospective single-arm phase II study. The study enrolled 91 patients aged 75 to 92 years. Eligible participants had histologically confirmed squamous cell carcinoma, stage II to IV disease based on the 8th edition of the American Joint Committee on Cancer (AJCC). All elderly patients (EPs) received dCRT with S-1. which was administered orally twice daily for 28 days. The radiotherapy dose was 61.2 Gy delivered in 34 fractions or 50.4 Gy delivered in 28 fractions. The primary endpoint was 2-year overall survival (OS), and the secondary endpoints were progression-free survival (PFS), local control rate (LCR), and safety. RESULTS: From July 2017 to July 2021, we enrolled EPs with ESCC who were treated at the Jiangsu Cancer hospital. As of August 1, 2023, the median follow-up of surviving EPs was 31.4 months (IQR: 25.2 to 72.6 months). 83 patients (91.2%) completed the whole course of treatment. The 2-year OS rate was 59.2%, and the PFS rate was 43.7%. The most common grade 1 to 2 adverse effects (AEs) were radiation esophagitis (79.1%), and then were radiation pneumonia (46.2%). Anemia (41.8%) was the most common of grade 1 to 2 hematologic toxicity. The incidence of grade 3 or above AEs was 24.2%, and the incidence of leukopenia was the highest (11.0%). There was not one death due to treatment-related toxicity. In a subgroup analysis of radiotherapy doses, we found no statistically significant differences in PFS (P = 0.465) and OS (P = 0.345) in EPs with ESCC who received 50.4 Gy and 61.2 Gy, and that patients in the 50.4 Gy group had lower dermatitis (P = 0.045) and anemia (P = 0.004). CONCLUSIONS: IF-IMRT combined with S-1 is a promising regimen for elderly ESCC. And the radiotherapy dose of 50.4 Gy remains the standard dose for EPs with ESCC undergoing CCRT.

Dosimetric effect of collimator rotation on intensity modulated radiotherapy and volumetric modulated arc therapy for rectal cancer radiotherapy.

INTRODUCTION: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) are the main radiotherapy techniques for treating and managing rectal cancer. Collimator rotation is one of the crucial parameters in radiotherapy planning, and its alteration can cause dosimetric variations. This study assessed the effect of collimator rotation on the dosimetric results of various IMRT and VMAT plans for rectal cancer. MATERIALS AND METHODS: Computed tomography (CT) images of 20 male patients with rectal cancer were utilized for IMRT and VMAT treatment planning with various collimator angles. Nine different IMRT techniques (5, 7, and 9 coplanar fields with collimator angles of 0°, 45°, and 90°) and six different VMAT techniques (1 and 2 full coplanar arcs with collimator angles of 0°, 45°, and 90°) were planned for each patient. The dosimetric results of various treatment techniques for target tissue (conformity index [CI] and homogeneity index [HI]) and organs at risk (OARs) sparing (parameters obtained from OARs dose-volume histograms [DVH]) as well as radiobiological findings were analyzed and compared. RESULTS: The 7-fields IMRT technique demonstrated lower bladder doses (V40Gy, V45Gy), unaffected by collimator rotation. The 9-fields IMRT and 2-arcs VMAT (excluding the 90-degree collimator) had the lowest V35Gy and V45Gy. A 90-degree collimator rotation in 2-arcs VMAT significantly increased small bowel and bladder V45Gy, femoral head doses, and HI values. Radiobiologically, the 90-degree rotation had adverse effects on small bowel NTCP (normal tissue complication probability). No superiority was found for a 45-degree collimator rotation over 0 or 30 degrees in VMAT techniques. CONCLUSION: Collimator rotation had minimal impact on dosimetric parameters in IMRT planning but is significant in VMAT techniques. A 90-degree rotation in VMAT, particularly in a 2-full arc technique, adversely affects PTV homogeneity index, bladder dose, and small bowel NTCP. Other evaluated collimator angles did not significantly affect VMAT dosimetrical or radiobiological outcomes.

Dosimetric Study and Robustness Analysis of Base Note Intensive Locked Field Radiotherapy for Left Breast Cancer.

Background: The locked vision plan can make the left breast cancer heart and lung organs dose. Objective: The aim of the present study was to compare the dosimetric differences between field-locked and field-split plans in intensity-modulated radiotherapy for left-sided breast cancer, to explore the effect of field-locking on the low-dose region, and to evaluate its robustness to the radiotherapy target, in order to provide a reference for the selection of clinical radiotherapy protocols. Methods: A total of 30 patients were selected after radical left breast cancer surgery, and 7-field locked-field and split-field plans were developed to compare the dose difference (∆D) between the target area and each organ at risk, and to introduce offsets of 3, 5 and 7 mm in six directions and recalculate the perturbed dose distributions, and to compare the ∆D between the original and the perturbed plans according to the robustness of the plans. Results: The results revealed that the D98%, D95% and Dmean values of the planning target volume (PTV) of the two plans differed little and were not statistically different. The locked field plan provided better protection for the left lung, right lung, heart, right breast and left anterior descending coronary artery. For PTV∆D98%, PTV∆D95%, PTV∆Dmean, the ∆D was higher for the Locked Fields plan, and for LungL∆5, LungL∆20 and Heart∆mean, the ∆D was higher for the original plan. Discussion: It was concluded that the field-locking plan could reduce the low-dose area of the affected lung and provide improved protection to the remaining critical organs, and the field-locking plan was more robust in protecting critical organs. Meanwhile, the field-locking plan showed higher sensitivity to positional deviation for target PTV.

Applying mixed-integer linear programming to the non-coplanar beam angle optimization of intensity-modulated radiotherapy for liver cancer.

Background: Currently, intensity-modulated radiation therapy (IMRT) is commonly used in radiotherapy clinics. However, designing a treatment plan with multiple beam angles depends on the experience of human planners, and is mostly achieved using a trial-and-error approach. It is preferrable but challenging to solve this issue automatically and mathematically using an optimization approach. The goal of this study is to develop a mixed-integer linear programming (MILP) approach for the beam angle optimization (BAO) of non-coplanar IMRT for liver cancer. Methods: MILP models for the BAO of both coplanar and non-coplanar IMRT treatment plans were developed. The beam angles of the IMRT plans were first selected by the MILP model built using mathematical optimization software. Next, the IMRT plans with the selected beam angles was created in a commercial treatment planning system. Finally, the fluence map and dose distribution of the IMRT plans were generated under pre-defined dose-volume constraints. The IMRT plans of 10 liver cancer patients previously treated at our institute were used to assessed the proposed MILP models. For each patient, both coplanar and non-coplanar IMRT plans with beam angles optimized by the MILP models were compared with the IMRT plan clinically approved by physicians. Results: The MILP model-guided IMRT plans showed reduced doses for most of the organs at risk (OARs). Compared with the IMRT plans clinically approved by physicians, the doses for the spinal cord (28.5 vs. 36.1, P=0.001<0.05) and liver (27.6 vs. 29.1, P=0.005<0.05) decreased significantly in the IMRT plans with non-coplanar beams selected by the MILP models. Conclusions: The MILP model is an effective tool for the BAO in coplanar and non-coplanar IMRT treatment planning. It facilitates the automation of IMRT treatment planning for current high-precision radiotherapy.

Advanced gastric cancer with peritoneal oligometastases treated with adaptive radiotherapy and concurrent chemotherapy.

BACKGROUND: There are no reports of concurrent chemoradiotherapy for gastric cancer with peritoneal oligometastases. CASE DESCRIPTION: A 70-year-old man with gastric cancer and peritoneal oligometastases received concurrent adaptive radiotherapy and oral S-1. After radiotherapy, S-1 was discontinued, and 2 years later the tumor had completely regressed, with no recurrence or metastasis 6 years after radiotherapy. CONCLUSION: Peritoneal oligometastatic gastric cancer may be a candidate for curative treatment with concurrent adaptive radiotherapy and oral S-1.

Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios as Predictors of Dysphagia Severity and Quality of Life in Nasopharyngeal Cancer Patients after Intensity Modulated Radiotherapy (IMRT).

Background: Patients treated with definitive radiotherapy for nasopharyngeal carcinoma (NPC) develop severe dysphagia, affecting their quality of life. Traditional prognosis biomarkers are insufficient, leading to a search for new predictors like neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). Methods: We retrospectively enrolled 44 NPC patients who underwent definitive radiotherapy between 2010 and 2018. EQUATOR and STROBE network guidelines were adopted. Pre-treatment evaluations were conducted, and post-treatment oropharyngeal dysphagia was assessed using the Sydney Swallow Questionnaire (SSQ) and FEES, then assigning a Dysphagia Outcome and Severity Scale (DOSS) level. Patients were divided based on NLR and PLR cut-offs, comparing subjective dysphagia (SSQ) scores and DOSS results at baseline and after a 5-year follow-up. Multiple linear regression was used for analysis. Results: At baseline, the mean NLR was 2.52 ± 1.10, and the PLR was 208.40 ± 94.35. Multivariate analysis indicated NLR and PLR as significant predictors of DOSS outcomes (p < 0.001). Conclusions: Baseline inflammation markers, such as NLR and PLR, may be used to predict dysphagia severity in NPC patients undergoing definitive radiotherapy. These markers could help identify patients at higher risk for severe dysphagia and implement tailored therapeutic and rehabilitative strategies to improve their quality of life. Further studies with larger cohorts are needed to confirm these findings and explore additional prognostic factors for dysphagia outcomes in NPC patients.