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This study investigates the influence of calculation accuracy in peripheral low-dose regions on the gamma pass rate (GPR), utilizing the Acuros XB (AXB) algorithm and ArcCHECK™ measurement. The effects of varying small field sizes, dose grid sizes, and split-arc techniques on GPR were analyzed. Various small field sizes were employed. Thirty-two single-arc plans with dose grid sizes of 2 mm and 1 mm and prescribed doses of 2, 5, 10, and 20 Gy were calculated using the AXB algorithm. In total, 128 GPR plans were examined. These plans were categorized into three sub-fields (3SF), four sub-fields (4SF), and six sub-fields (6SF). The GPR results deteriorated with smaller target sizes and a 2 mm dose grid size in a single arc. A similar degradation in GPR was observed with smaller target sizes and a 1 mm dose grid size. However, the 1 mm dose grid size generally resulted in better GPR compared with the 2 mm dose grid size for the same target sizes. The GPR improved with finer split angles and a 2 mm dose grid size in the split-arc method. However, no statistically significant improvement was observed with finer split angles and a 1 mm dose grid size. This study demonstrates that coarser dose grid sizes result in lower GPRs in peripheral low-dose regions as calculated by AXB with ArcCHECK™ measurement. To enhance GPR, employing split-arc methods and finer dose grid sizes could be beneficial. [ABSTRACT FROM AUTHOR]

Background: Postoperative chemoradiotherapy is recommended for patients with head and neck squamous cell carcinoma with positive margins or extracapsular extension at high risk of recurrence. However, high-dose radiotherapy in the head and neck region often causes severe acute and late radiation-related adversities. In our institution, the radiation dose has been relatively lower than that used in Western countries to reduce radiation-related toxicities. Therefore, in this study, we examined the treatment outcomes of low-dose postoperative chemoradiotherapy. Methods: The outcomes of 90 consecutive head and neck squamous cell carcinoma patients who received postoperative radiotherapy between June 2009 and December 2016 were retrospectively analyzed. All patients received postoperative three-dimensional conformal radiotherapy with or without concurrent systemic chemotherapy. The median patient age was 65 years. Concurrent chemoradiotherapy was administered at a total dose of 50.4 Gy in 28 fractions (daily fraction, 1.8 Gy). High-risk patients received 10.8 Gy of boost irradiation in six fractions. For radiotherapy alone, the irradiation dose was up to 54 Gy in 30 fractions and 64.8 Gy in 36 fractions for high-risk patients to increase the treatment intensity. Results: The median follow-up period was 40.5 months. The 3-year locoregional control and overall survival rates were 67.5% and 82.7%, respectively. A significantly higher proportion of patients with oral cavity carcinoma experienced locoregional failure (p = 0.004). The acute adverse events were mild, and the only late adverse event was grade 3 dysphagia (n = 3). Conclusion: This study suggests that de-escalation of the postoperative radiation dose can potentially reduce the severe adverse events of irradiation in patients while ensuring its effectiveness. In patients with oral cavity carcinoma, it might be necessary to increase the radiation dose. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy of chemoembolization for inoperable metastatic epidural spinal cord compression (MESCC) refractory to re-radiotherapy. Methods: Nineteen consecutive patients with recurrent MESCC after re-radiotherapy who had undergone chemoembolization were retrospectively analyzed. Outcome measures were pain relief rate, neurological improvement rate, objective response rate, and adverse events. MESCC degree classification was assessed using Bilsky grades. Pain assessment was performed using Numerical Rating Scale, and neurological function was evaluated using the Frankel classification. Results: The median follow-up period was 7 (range 2–44) months. All participants had MESCC grade 2 or higher and had severe pain. Fifteen patients (79%) had neurological deficits, and ten had Frankel classification C and five had D. Symptoms were relieved in almost all patients the day following chemoembolization. Pain relief was achieved in 18 of 19 (95%) patients; the median decrease in Numerical Rating Scale score was 8 (range 0–10; p < 0.001). Neurological improvement was achieved in 11 of 15 patients (73%); the median increase in Frankel classification was 1 (range 0–2; p = 0.006). Ten of 19 (53%) patients showed a reduction in MESCC; the median decrease in Bilsky grade was 1 (range 0–2; p = 0.005). There was no correlation between the change in Bilsky grade and pain relief (p = 0.421). However, the decrease in Bilsky grade significantly improved neurological symptoms (p = 0.01). No serious adverse events occurred. Conclusion: Chemoembolization may be a useful palliative treatment modality for MESCC refractory to re-radiotherapy. Level of Evidence: Level 3b, Follow up Study. [ABSTRACT FROM AUTHOR]

Purpose: Fractures are known to shorten life expectancy and worsen the quality of life. The risk of fractures after radiation therapy in cervical cancer patients is known to be multifactorial. In this study, we examined risk factors for fractures in cervical cancer patients, especially by evaluating bone densities and DVH parameters for fractured bones. Materials and Methods: For 42 patients, clinical characteristics, pretreatment CT bone densities, and radiation dose were compared between patients with and without fractures. Results: Posttreatment fractures occurred in 25 bones among ten patients. Pretreatment CT bone densities were significantly lower in patients with fractures (P < 0.05–0.01 across sites, except for the ilium and the ischium). Although DVH parameters were also significantly associated with fractures in univariate analysis, only CT densities were significantly associated with fractures in multivariate analysis. Conclusion: Pretreatment CT densities of spinal and pelvic bones, which may reflect osteoporosis, have a significant impact on the risk for posttreatment fractures. [ABSTRACT FROM AUTHOR]

Background: This prospective study investigated the feasibility, toxicity, and oncologic outcomes of definitive radiotherapy (RT) consisting of whole pelvic radiotherapy with no central shielding (noCS-WPRT) and CT-based intracavitary brachytherapy (ICBT) in Japanese patients with cervical cancer. Methods: Patients with cervical cancer of FIGO stages IB1–IVA were eligible. The treatment protocol consisted of noCS-WPRT of 45 Gy in 25 fractions and CT-based high dose-rate ICBT of 15 or 20 Gy in 3 or 4 fractions prescribed at point A. The prescribed ICBT dose was decreased if the manual dwell time/position optimization failed to meet organs-at-risk constraints. Graphical optimization and additional interstitial needles were not applied. Results: We enrolled 40 patients. FIGO stages were IB1: 11, IB2: 13, IIA2: 1, IIB: 11, IIIB: 3, and IVA: 1. Median (range) pretreatment tumor diameter was 47 (14–81) mm. Point A doses were decreased in 19 of 153 ICBT sessions (12%). The median follow-up duration was 33 months. The 2-year rates of pelvic control, local control (LC), and progression-free survival were 83%, 85%, and 75%, respectively. Pre-ICBT tumor diameter, high-risk clinical target volume (HR-CTV), total HR-CTV D90, and overall treatment time (OTT) significantly affected LC. Late adverse events (grade ≥ 3) were observed in 3 patients (2 in the bladder, 1 in the rectum). Conclusions: Definitive RT consisting of noCS-WPRT and CT-based ICBT was feasible for Japanese patients with cervical cancer. To further improve LC, additional interstitial needles for patients with a large HR-CTV and shorter OTT should be considered. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to compare the efficacy of radiotherapy (RT) combined with transcatheter arterial chemoembolization (TACE) with RT alone for the treatment of bone metastases from renal cell carcinoma (RCC).Methods: We included in this retrospective study 25 RCC patients (28 bone metastases), who were treated with RT at our institution. Patients were divided into two groups: patients treated with RT alone (monotherapy group; n = 17) and those treated with RT combined with TACE (combined therapy group; n = 11). The administered median RT dose was 30 Gy in 10 fractions. Anti-cancer agents used in TACE were cisplatin (median dose, 50 mg) and carboplatin (median dose, 240 mg) for patients with reduced renal function. We evaluated the objective response, post-RT-skeletal-related event (PR-SRE)-free rate, and adverse events associated with treatment for each group.Results: The objective response rates for bone metastases in the monotherapy and combined therapy groups were 33% and 82%, respectively (p = 0.009). The 2-year PR-SRE-free rate in the monotherapy and combined therapy groups was 41.8% and 100%, respectively (p = 0.009). The objective response and PR-SRE-free rates were significantly superior in the combined therapy than in the monotherapy group. There were no significant differences in adverse events or survival between the two groups.Conclusion: RT combined with TACE is a promising treatment for bone metastases from RCC, as it results in higher objective response, and PR-SRE-free rates compared with RT alone.Key Points: • Skeletal-related events (SREs) are common in patients with bone metastases from renal cell carcinoma (RCC). • Radiotherapy (RT) provides pain relief in patients with bone metastases from RCC, but rarely achieves objective response. • Combination of RT with transcatheter arterial chemoembolization results in higher objective response and post-RT-SRE-free rates compared with RT alone and is a promising treatment for bone metastases from RCC, as it. [ABSTRACT FROM AUTHOR]