Development of Magnetic Resonance-Compatible Head Immobilization Device and Initial Experience of Magnetic Resonance-Guided Radiation Therapy for Central Nervous System Tumors.

PURPOSE: We aimed to develop and investigate positional reproducibility using a fixation device (Unity Brain tumor Immobilization Device [UBID]) in patients with brain tumor undergoing magnetic resonance (MR)-guided radiation therapy (RT) with a 1.5 Tesla (T) MR-linear accelerator (MR-LINAC) to evaluate its feasibility in clinical practice and report representative cases of patients with central nervous system (CNS) tumor. MATERIALS AND METHODS: Quantitative analysis was performed by comparing images obtained by placing only the MR phantom on the couch with those obtained by placing UBID next to the MR phantom. Twenty patients who underwent RT for CNS tumors using 1.5T MR-LINAC between June and October 2022 were retrospectively analyzed. Among them, 5 did not use UBID, whereas 15 used UBID. The positional reproducibility of UBID was evaluated using the median interfractional and intrafractional errors in the first 10 fractions. RESULTS: Each MR quality factor of the MR phantom with UBID satisfied the criteria presented by Elekta. Median values of median shifts in the mediolateral, anteroposterior, and craniocaudal axes for interfractional errors were 2.98, 2.35, and 1.40 mm, respectively. For intrafractional errors, the median values were 0.05, 0.03, and 0.06 mm, respectively. The median values of the median rotations in pitch, roll, and yaw for both interfractional and intrafractional rotations were 0.00°. One patient diagnosed with an optic nerve sheath meningioma received RT with motion monitoring during irradiation. In 2 patients, changes in the tumor cavity and residual lesions were observed in the MRI obtained using 1.5T MR-LINAC on the day of the first treatment and immediately before the 21st fraction, respectively; therefore, offline/online adaptation was performed. CONCLUSIONS: The reproducible and immobile UBID is clinically feasible in patients with CNS tumors receiving RT with 1.5T MR-LINAC. Based on our initial experience, we developed a workflow for 1.5T MR-LINAC treatment of CNS tumors.

Dosimetric Comparison of CPAP and DIBH for Left-sided Breast Cancer Radiation Therapy.

Purpose: Despite the increasing interest in using continuous positive airway pressure (CPAP) in radiation therapy (RT), direct comparisons with the more widely used deep inspiration breath-hold (DIBH) have been limited. This planning study aimed to offer comprehensive geometric and dosimetric evidence by comparing CPAP and DIBH-based RT plans. Materials and Methods: A retrospective data set of 35 patients with left-sided breast cancer with planning computed tomography scans under three breathing conditions (free breathing (FB), CPAP with 10 cmH2O pressure, and DIBH) was collected. Volumetric arc therapy plans aimed for 95% dose coverage to 95% of the planning target volume with a maximum dose below 107%. A comparative dosimetric analysis among the three plans was conducted. Additionally, geometric differences were assessed by calculating the minimum distance between the heart and the clinical target volume (CTV) in each planning computed tomography. Results: CPAP and DIBH plans demonstrated comparable mean heart doses (1.05 Gy), which were significantly lower than the FB plan (1.34 Gy). The maximum dose to the left anterior descending artery was smallest in the CPAP plan (4.44 Gy), followed by DIBH (4.73 Gy) and FB (7.33 Gy) plans. Other organ-at-risk doses for CPAP and DIBH were similar, with mean contralateral breast doses of 2.27 and 2.21 Gy, mean ipsilateral lung doses of 4.09 and 4.08 Gy, V20 at 6.11% and 6.31%, and mean contralateral lung doses of 0.94 and 0.92 Gy, respectively. No significant difference was found in the minimum heart-to-CTV distance between CPAP and DIBH. DIBH exhibited the greatest lung volume (3908 cc), followed by CPAP (3509 cc), and FB(2703 cc). Conclusions: The comparison between CPAP and DIBH shows their similarity in both geometric and dosimetric aspects, providing strong evidence for CPAP's effectiveness and feasibility in RT. This suggests its potential as an alternative to DIBH for patients with left-sided breast cancer.

Choosing the right adjuvant therapy for stage III-IVA endometrial cancer: A comparative analysis of chemoradiotherapy and chemotherapy.

OBJECTIVE: The optimal adjuvant treatment for patients with locally advanced endometrial cancer (EC) remains debatable. We comparatively analyzed recurrence patterns and survival outcomes in patients with stage III-IVA EC treated with adjuvant chemotherapy (CT) exclusively or combined with radiotherapy (CRT). METHODS: We retrospectively analyzed 184 patients treated for stage III-IVA EC at 2 tertiary institutions between 2010 and 2021. All patients underwent standard primary surgery and received either CT alone (n = 89) or CRT (n = 95) as an adjuvant treatment. We compared the failure patterns, recurrence-free survival (RFS), and overall survival (OS) between the CT and CRT groups. RESULTS: The median follow-up period was 54.8 months. Most patients underwent pelvic (94.6%) or para-aortic (75.5%) lymphadenectomies. The 5-year RFS was 69.2% with CRT versus 56.3% with CT (P = 0.038), and 5-year OS was 86.1% versus 78.9% (P = 0.357). Pelvic and para-aortic recurrence rates were significantly higher in the CT group (pelvic: 29.2%; para-aortic: 20.2%) than in the CRT group (pelvic: 10.5%; para-aortic: 6.3%). The CRT group showed a higher rate of distant recurrence (CRT, 23.2% vs. CT, 14.6%) however, the 5-year cumulative incidence of distant recurrence was not significantly different between the two groups (CRT, 28% vs. CT, 35%). CONCLUSIONS: This study highlights the potential benefits of adjuvant CRT in patients with stage III-IVA EC. The incorporation of molecular classification is necessary to derive optimal personalized adjuvant treatment strategies for this patient population.

Risk of on-treatment lymphopenia is associated with treatment outcome and efficacy of consolidation immunotherapy in patients with non-small cell lung cancer treated with concurrent chemoradiotherapy.

BACKGROUND AND PURPOSE: The ability of the effective dose to immune cells (EDIC) and the pre-radiotherapy (RT) absolute lymphocyte count (ALC) to predict lymphopenia during RT, treatment outcomes, and efficacy of consolidation immunotherapy in patients with locally advanced non-small cell lung cancer was investigated. METHODS AND MATERIALS: Among 517 patients treated with concurrent chemoradiotherapy, EDIC was calculated using the mean doses to the lungs, heart, and total body. The patients were grouped according to high and low EDIC and pre-RT ALC, and the correlations with radiation-induced lymphopenia and survival outcomes were determined. RESULTS: Altogether, 195 patients (37.7%) received consolidation immunotherapy. The cutoff values of EDIC and pre-RT ALC for predicting severe lymphopenia were 2.89 Gy and 2.03 × 109 cells/L, respectively. The high-risk group was defined as EDIC ≥ 2.89 Gy and pre-RT ALC < 2.03 × 109 cells/L, while the low-risk group as EDIC < 2.89 Gy and pre-RT ALC ≥ 2.03 × 109 cells/L, and the rest of the patients as the intermediate-risk group. The incidences of severe lymphopenia during RT in the high-, intermediate-, and low-risk groups were 90.1%, 77.1%, and 52.3%, respectively (P < 0.001). The risk groups could independently predict both progression-free (P < 0.001) and overall survival (P < 0.001). The high-risk group showed a higher incidence of locoregional and distant recurrence (P < 0.001). Consolidation immunotherapy showed significant survival benefit in the low- and intermediate-risk groups but not in the high-risk group. CONCLUSIONS: The combination of EDIC and pre-RT ALC predicted severe lymphopenia, recurrence, and survival. It may potentially serve as a biomarker for consolidation immunotherapy.

Impact of boost sequence in concurrent chemo-radiotherapy on newly diagnosed IDH-wildtype glioblastoma multiforme.

BACKGROUND: The standard of care for glioblastoma multiforme (GBM) is maximal surgical resection followed by conventional fractionated concurrent chemoradiotherapy (CCRT) with a total dose of 60 Gy. However, there is currently no consensus on the optimal boost technique for CCRT in GBM. METHODS: We conducted a retrospective review of 398 patients treated with CCRT between 2016 and 2021, using data from two institutional databases. Patients were divided into two groups: those receiving sequential boost (SEB, N = 119) and those receiving simultaneous integrated boost (SIB, N = 279). The primary endpoint was overall survival (OS). To minimize differences between the SIB and SEB groups, we conducted propensity score matching (PSM) analysis. RESULTS: The median follow-up period was 18.6 months. Before PSM, SEB showed better OS compared to SIB (2-year, 55.6% vs. 44.5%, p = 0.014). However, after PSM, there was no significant difference between two groups (2-year, 55.6% vs. 51.5%, p = 0.300). The boost sequence was not associated with inferior OS before and after PSM (all p-values > 0.05). Additionally, the rates of symptomatic pseudo-progression were similar between the two groups (odds ratio: 1.75, p = 0.055). CONCLUSIONS: This study found no significant difference in OS between SEB and SIB for GBM patients treated with CCRT. Further research is needed to validate these findings and to determine the optimal boost techniques for this patient population.

Machine learning­based radiomics models for prediction of locoregional recurrence in patients with breast cancer.

Locoregional recurrence (LRR) is the predominant pattern of relapse after definitive breast cancer treatment. The present study aimed to develop machine learning (ML)-based radiomics models to predict LRR in patients with breast cancer by using preoperative magnetic resonance imaging (MRI) data. Data from patients with localized breast cancer that underwent preoperative MRI between January 2013 and December 2017 were collected. Propensity score matching (PSM) was performed to adjust for clinical factors between patients with and without LRR. Radiomics features were obtained from T2-weighted with and without fat-suppressed MRI and contrast-enhanced T1-weighted with fat-suppressed MRI. In the present study five ML models were designed, three base models (support vector machine, random forest, and logistic regression) and two ensemble models (voting model and stacking model) composed of the three base models, and the performance of each base model was compared with the stacking model. After PSM, 28 patients with LRR and 86 patients without LRR were included. Of these 114 patients, 80 patients were randomly selected to train the models, and the remaining 34 patients were used to evaluate the performance of the trained models. In total, 5,064 features were obtained from each patient, and 47-51 features were selected by applying variance threshold and least absolute shrinkage and selection operator. The stacking model demonstrated superior performance in area under the receiver operating characteristic curve (AUC), with an AUC of 0.78 compared to a range of 0.61 to 0.70 for the other models. An external validation study to investigate the efficacy of the stacking model of the present study was initiated and is still ongoing (Korean Radiation Oncology Group 2206).

Vertebral compression fracture after stereotactic ablative radiotherapy in patients with oligometastatic bone lesions from hepatocellular carcinoma.

Background and purpose: Stereotactic ablative radiotherapy (SABR) is popularly used to treat bone metastasis. Despite its efficacy, adverse events, including vertebral compression fracture (VCF), are frequently observed. Here, we investigated VCF risk after SABR for oligometastatic vertebral bone metastasis from hepatocellular carcinoma. Materials and methods: A total of 84 patients with 144 metastatic bone lesions treated at three institutions between 2009 and 2019 were retrospectively reviewed. The primary endpoint was VCF development, either new or progression of a pre-existing VCF. VCFs were assessed using the spinal instability neoplastic score (SINS). Results: Among 144 spinal segments, 26 (18%) had pre-existing VCF and 90 (63%) had soft tissue extension. The median biologically effective dose (BED) was 76.8 Gy. VCF developed in 14 (12%) of 118 VCF-naïve patients and progressed in 20 of the 26 with pre-existing VCF. The median time to VCF development was 6 months (range, 1-12 months). The cumulative incidence of VCF at 12 months with SINS class I, II and III was 0%, 26% and 83%, respectively (p < 0.001). Significant factors for VCF development were pre-existing VCF, soft tissue extension, high BED, and SINS class in univariate analysis, and pre-existing VCF in multivariate analysis. Of the six components of SINS, pain, type of bone lesion, spine alignment, vertebral body collapse, and posterolateral involvement were identified as predictors of VCF development. Conclusion: SABR for oligometastatic vertebral bone lesions from HCC resulted in a substantial rate of new VCF development and pre-existing VCF progression. Pre-existing VCF was significant risk factor for VCF development, which require special attention in patient care. Patients with SINS class III should be considered surgical treatment rather than upfront SABR.

Risk factors for lower extremity lymphedema after surgery in cervical and endometrial cancer.

OBJECTIVE: Lower extremity lymphedema (LEL) is a well-known adverse effect related to cervical and endometrial cancer (CEC); however, very few studies have elucidated the clinicopathologic risk factors related to LEL. We investigated the incidence and risk factors in patients who received primary surgery and/or adjuvant radiotherapy (RT) or chemotherapy for CEC. METHODS: We retrospectively reviewed 2,565 patients who underwent primary surgery following CEC diagnosis between January 2007 and December 2020. LEL diagnosis was based on objective and subjective assessments by experts. We identified important predictors of LEL to construct a nomogram predicting individual risks of LEL. For internal validation of the nomogram, the original data were separated using the split-sample method in a 7:3 ratio of training data and test data. RESULTS: Overall, 858 patients (33.5%) received RT, 586 received external beam RT (EBRT), and 630 received intracavitary RT. During follow-up period, LEL developed in 331 patients, with an overall cumulative 5-year incidence of 13.3%. In multivariate analysis, age at primary treatment, use of docetaxel-based chemotherapy, type of hysterectomy, type of surgical pelvic lymph node (LN) assessment, number of dissected pelvic and para-aortic LNs, and EBRT field were the independent predictors of LEL. We subsequently developed the nomogram showing excellent predictive power for LEL. CONCLUSION: LEL is associated with various treatment modalities, and their interactions may increase the possibility of occurrences. De-escalation strategies for treatment modalities should be considered to reduce LEL in patients with CEC.

Treatment outcomes and radiotherapy deintensification strategies in human papillomavirus-associated tonsil cancer.

BACKGROUND: Human papillomavirus (HPV)-positive tonsil cancer has a better prognosis than HPV-negative tonsil cancer. Deintensification strategies to reduce or avoid radiotherapy (RT) for patients with HPV-associated tonsil cancer have been suggested. This study investigated the treatment outcomes of patients with HPV-associated tonsil cancer and suggested RT deintensification strategies. METHODS: A cohort of 374 patients with HPV-associated tonsil cancer treated with primary surgery or RT between 2008 and 2020 was retrospectively evaluated. Survival and locoregional control rates after primary surgery or RT were analyzed, and propensity score matching was performed to adjust for clinical factors. Pearson's chi-square or Fisher's exact test was used to compare categorical variables, and Student's t-test was used to compare continuous variables. The Kaplan-Meier method and log-rank test were used to assess overall survival, progression-free survival, and locoregional failure (LRF). RESULTS: No significant differences in survival or LRF were observed between the primary surgery and RT groups. Subgroup analysis was conducted for patients who underwent primary surgery. Advanced pathological N stage, negative contralateral nodes at diagnosis, abutting or positive surgical margins, and no adjuvant RT were independent risk factors for LRF. Advanced pathological T stage was an independent risk factor for LRF in patients who underwent primary surgery without subsequent adjuvant RT. None of the patients with pathological complete remission (CR) after induction chemotherapy died or experienced LRF. CONCLUSIONS: Our study revealed that the outcomes of primary surgery and primary RT in HPV-positive tonsil cancer were similar after adjusting for clinical factors. Primary RT might be considered instead of surgery in patients with advanced pathological T stage. In the case of pathological CR after induction chemotherapy, deintensification for adjuvant RT should be considered.

Risk of Diabetes Mellitus after Radiotherapy for Gastric Mucosa-Associated Lymphoid Tissue Lymphoma.

The long-term effect of radiation on the pancreas in pediatric patients has been studied without individual radiation dosimetric data. This study investigated the effect of radiotherapy on the risk of developing diabetes mellitus (DM) in patients with gastric mucosa-associated lymphoid tissue lymphoma (GML), using individual radiation dosimetric analysis. Retrospective analysis reviewed the data of 225 patients without a history of DM receiving curative treatment for stage IE GML. Involved-site radiotherapy was delivered to the whole stomach in 83 patients. The pancreas was delineated in each patient's computed tomography scan for dosimetric analysis. At a median follow-up of 49.0 months, the 5-year cumulative incidence of DM was 4.5%, 9.6%, and 1.6% in all patients, patients who received radiotherapy, and patients who did not receive radiotherapy, respectively (p = 0.009). Mean pancreatic dose (Dmean; p = 0.009), sex (p = 0.043), and body mass index (BMI; p = 0.008) were independently associated with DM. Using recursive partitioning analysis, patients were classified into low, intermediate, and high-risk groups, with 5-year DM incidence rates of 0.0%, 3.1%, and 15.6%, respectively (p < 0.001). Incidental irradiation of the pancreas can increase the risk of DM, which may be stratified according to patient sex and BMI.

Association of Sinoatrial Node Radiation Dose With Atrial Fibrillation and Mortality in Patients With Lung Cancer.

Importance: Atrial fibrillation (AF) can develop following thoracic irradiation. However, the critical cardiac substructure responsible for AF has not been properly studied. Objective: To describe the incidence of AF in patients with lung cancer and determine predictive cardiac dosimetric parameters. Design, Setting, and Participants: This retrospective cohort study was performed at a single referral center and included 239 patients diagnosed with limited-stage small cell lung cancer (SCLC) and 321 patients diagnosed with locally advanced non-small cell lung cancer (NSCLC) between August 2008 and December 2019 who were treated with definitive chemoradiotherapy. Exposures: Radiation dose exposure to cardiac substructures, including the chambers, coronary arteries, and cardiac conduction nodes, were calculated for each patient. Main Outcomes and Measures: Main outcomes were AF and overall survival. Results: Of the 239 and 321 patients with SCLC and NSCLC, the median (IQR) age was 68 (60-73) years and 67 (61-75) years, and 207 (86.6%) and 261 (81.3%) were men, respectively. At a median (IQR) follow-up time of 32.7 (22.1-56.6) months, 9 and 17 patients experienced new-onset AF in the SCLC and NSCLC cohorts, respectively. The maximum dose delivered to the sinoatrial node (SAN Dmax) exhibited the highest predictive value for prediction of AF. A higher SAN Dmax significantly predicted an increased risk of AF in patients with SCLC (adjusted hazard ratio [aHR], 14.91; 95% CI, 4.00-55.56; P < .001) and NSCLC (aHR, 15.67; 95% CI, 2.08-118.20; P = .008). However, SAN Dmax was not associated with non-AF cardiac events. Increased SAN Dmax was significantly associated with poor overall survival in patients with SCLC (aHR, 2.68; 95% CI, 1.53-4.71; P < .001) and NSCLC (aHR, 1.97; 95% CI, 1.45-2.68; P < .001). Conclusions and Relevance: In this cohort study, results suggest that incidental irradiation of the SAN during chemoradiotherapy may be associated with the development of AF and increased mortality. This supports the need to minimize radiation dose exposure to the SAN during radiotherapy planning and to consider close follow-up for the early detection of AF in patients receiving thoracic irradiation.

Risk factor analysis of dental implants in patients with irradiated head and neck cancer.

BACKGROUND: We investigated dental implant outcomes in patients who had previously received radiotherapy (RT) for head and neck malignancies. METHODS: We reviewed 90 dental implants in 27 patients who received RT for head and neck cancer and received dental implants afterwards. The cumulative implant survival rate (CISR) was calculated. In addition, the implant quality was assessed using "Health Scale for Dental Implants." RESULTS: The CISR at 3 years was 79.6%. The mean radiation dose at the implant site (Dmean ) was identified as an independent prognostic factor for implant survival. No implant failed if Dmean was less than 38 Gy. Regarding implant quality, dental implants in grafted bone and Dmean were independent risk factors. CONCLUSIONS: Dmean was identified as an independent prognostic factor for implant survival and quality. Dental implants can be safely considered when Dmean is lower than 38 Gy.

Skull Base Metastasis from Hepatocellular Carcinoma: Clinical Presentation and Efficacy of Radiotherapy.

Purpose: Skull base metastasis (SBM) from hepatocellular carcinoma (HCC) presents detrimental survival outcomes with cranial nerve symptoms; however, they have received little attention. This study aimed to investigate the clinical presentation and efficacy of radiation therapy (RT) in patients with SBM from HCC. Patients and Methods: We identified patients with SBM from HCC in Yonsei Cancer Center from 2005 to 2019. Image evaluations and SBM-related symptoms were reviewed. Overall survival was calculated using the Kaplan-Meier method and compared through the Log rank test. The oligometastasis group included patients with less than five foci of tumors, while the extensive metastasis group presented five or more sites. Results: The incidence of SBM from HCC was 1.5% (58/3793 patients), commonly found in the middle cranial fossa. SBM associated symptoms presented in 51 patients, and the most common were head and neck area pain, and orbital symptoms, The palliation rate after RT was 65% (24/39 patients) for overall symptoms and 83.3% (20/24 patients) for cranial nerve symptoms. In whole cohort, overall survival was analyzed, and the median overall survival of patients with oligometastasis was better than extensive metastasis (23.7 months vs 1.8 months, p < 0.001). In subgroup who received RT (39 patients), the median overall survival was 23.7 and 2.7 months for patients with oligo and extensive metastasis, respectively (p < 0.001). Conclusion: This study confirmed clinical features of SBM from HCC. Overall survival was generally poor, but patients presenting oligometastasis seemed to have possibility of relative long-term survival. Although radiation was effective in SBM-induced symptom relief, dose-response relationship in local control rate and overall survival needs further studies with larger number of patients.

Pulmonary toxicity of craniospinal irradiation using helical tomotherapy.

Craniospinal irradiation using helical tomotherapy (HT-CSI) has advantages in aspects of homogeneous dose distribution. Physicians, however, still have concerns of pulmonary toxicity due to HT-CSI's relatively large, low-dose irradiated volume from continuous and 360° rotation delivery. In this study, we investigated the pulmonary toxicity of HT-CSI. We retrospectively reviewed 105 patients who received HT-CSI between January 2014 and December 2019. Grade 2 + pulmonary toxicities were evaluated. Intensive systemic treatment was defined as systemic treatment administration before, during, and after HT-CSI. VX Gy was defined as % volume receiving ≥ X Gy. Thirteen patients (12.4%) presented with grade 2 + pulmonary toxicities after HT-CSI. Of these patients, only one experienced grade 2 radiation pneumonitis combined with pembrolizumab-induced pneumonitis. Conversely, pneumonia was observed in 12 patients. Intensive systemic treatment (p = 0.004), immunosuppressive drugs (p = 0.031), and bilateral lung V5 Gy ≥ 65% (p = 0.031) were identified as independent risk factors for pneumonia. The risk factor for pneumonia in pediatric patients were immunosuppressive drugs (p = 0.035) and bilateral lung V5 Gy ≥ 65% (p = 0.047). HT-CSI can be a safe treatment modality with tolerable pulmonary toxicities. Intensive systemic treatment, immunosuppressive drugs, and bilateral lung V5 Gy ≥ 65% were significantly associated with pneumonia. In these patients, close follow-up should be considered for proper management of pneumonia.

Medical student education through flipped learning and virtual rotations in radiation oncology during the COVID-19 pandemic: a cross sectional research.

BACKGROUND: The COVID-19 pandemic has stripped many medical students worldwide of their right to quality education. In response, we developed hybrid courses involving aspects of both online and in-person teaching for radiation oncology medical student clerkship. METHODS: We entitled students to customize their own rotation schedule using Google Forms and developed a flipped learning online class, which consisted of at least one video clip on basic knowledge of radiation oncology per day (yonsei-radonc.com). Students were instructed to watch online videos before the next day's discussion session. Required components of the medical education program (e.g., target drawing, site visits to treatment facilities) were also prepared and conducted in accordance with the appropriate level of social distancing measures. Finally, we conducted questionnaire surveys after the completion of the week-long course and clerkship. RESULTS: From March to June 2020, 110 fourth-year medical students undertook a clinical module in our 1-week radiation oncology program course. Each day, students completed the flipped learning prior to meeting with the educator and then participated in the online discussion session and conference. All activities were well performed as scheduled. Students' motivation was high, as was their overall satisfaction with the course. The students were satisfied with the online contents, flipped learning strategy, and instructors. CONCLUSIONS: We successfully integrated open and virtual educational platforms to improve access to and satisfaction with student clerkship. In the future "new normal," minimized face-to-face learning interactions, such as flipped learning, should be actively utilized for medical and other students' education.

Efficacy of radiotherapy for gastric bleeding associated with advanced gastric cancer.

BACKGROUND: Gastric bleeding negatively impacts the quality of life of patients with unresectable advanced gastric cancer and is frequently lethal. We investigated the efficacy of RT for palliation of gastric bleeding from gastric cancer and identified an optimal radiotherapy (RT) strategy. METHODS: The study analyzed 57 patients submitted to palliative RT for gastric bleeding associated with gastric cancer between January 2009 and February 2019. Changes in hemoglobin (Hb) levels were analyzed based on measurements taken before and immediately, 1 month, and 2 months after RT. Re-bleeding after RT was identified as either Hb level dropping to < 7.0 g/dL or the administration of a blood transfusion after RT. RESULTS: The median biologically effective dose (α/ß = 10) was 37.5 Gy (range 23.6-58.5). The most common regimen was 25 Gy in five fractions. The mean Hb levels before, immediately after, 1 month, and 2 months after RT (6.6, 9.7, 10.3, and 9.7 g/dL, respectively) were significantly higher than that before RT (all p < 0.001). No significant differences in re-bleeding rates were observed according to total dose, fractional dose, and fraction number. Gastric tumor response evaluated by computed tomography within 2 months after RT showed partial responses were more frequent in patients achieving bleeding control (25.0% vs. 10.8%, p = 0.023) and overall survival was significantly improved for bleeding control within 3 months after RT (median, 15.4 vs. 10.0 weeks, p = 0.048). CONCLUSIONS: RT was an effective modality for gastric bleeding control in gastric cancer, which can be achieved with a short course scheme with five fractions.

Intracranial failure after hippocampal-avoidance prophylactic cranial irradiation in limited-stage small-cell lung cancer patients.

We evaluated intracranial failure after hippocampus-avoidance-prophylactic cranial irradiation (HA-PCI) for limited-stage small-cell lung cancer (SCLC). Data of 106 patients who received PCI with 25 Gy were retrospectively reviewed. The patients were divided into two groups based on whether they underwent HA-PCI: the HA-PCI group (n = 48) and the conventional PCI (C-PCI) group (n = 58). Twenty-one patients experienced intracranial failure: 11 and 10 patients in the C-PCI and HA-PCI groups, respectively. Using the log-rank test, the intracranial failure rate was not significantly different between the groups (p = 0.215). No clinical factor was significantly associated with intracranial failure in multivariate Cox regression analysis, but HA-PCI tended to be associated with increased incidence of intracranial failure (HR 2.87, 95% CI 0.86-9.58, p = 0.087). Among patients who received HA-PCI, two developed peri-hippocampal recurrence. A higher thoracic radiotherapy dose (≥ 60 Gy) was significantly associated with DFS (HR 0.52, p = 0.048) and OS (HR 0.35, p = 0.003). However, HA-PCI was associated with neither DFS nor OS. Although HA-PCI may be associated with an increased risk of intracranial failure, HA-PCI did not impair disease control or survival. Future prospective randomized trials are needed to reach a definite conclusion.

Practical aspects of the application of helical tomotherapy for craniospinal irradiation.

We investigated the practical aspects of the application of craniospinal irradiation using helical tomotherapy (HT-CSI) by evaluating interfractional setup errors and intrafractional movement during each treatment in 83 patients undergoing HT-CSI between January 2014 and December 2018. Interfractional setup errors in each axis (mediolateral; ML, craniocaudal; CC, and anteroposterior; AP) were assessed as differences between pre-treatment megavoltage computed tomography (MVCT) images scanned (zygomatic arch to the C4 spine) and planning CT images. Intrafractional movements were evaluated as the difference between pre-treatment and post-treatment MVCT (T12-L4 spine) images at each fraction. Median interfractional setup error was acceptable in every axis (ML: 1.6 mm, CC: 1.9 mm, AP: 3.1 mm). Seven patients (8.4%) experienced significant intrafractional displacement from 1 to 10 fractions (0.34% for ML, 0.74% for CC, 1.21% for AP). Weight loss grade 1+ during treatment (p = 0.016) was an independent risk factor for significant intrafractional displacement. The risk factor for significant intrafractional movement in pediatric patients was weight loss grade 1+ (p = 0.020), while there was no factor in adults. HT-CSI could be a feasible treatment modality with acceptable setup verification. Inter- and intrafractional errors were acceptable; paying attention to weight loss during treatment is necessary, especially in pediatric patients.