Background: Tri-weekly cisplatin and radiotherapy (CDDP + RT) is a standard of care for locally advanced head and neck squamous cell carcinoma (LA-HNSCC) but is sometimes challenging to complete in older patients. Weekly CDDP + RT has shown mild toxicity compared to tri-weekly CDDP + RT for LA-HNSCC and is a promising option for older adults. We aimed to report the treatment outcomes and prognostic factors in patients with LA-HNSCC treated with weekly CDDP + RT. Methods: We analyzed patients aged ≥ 70 years who started weekly CDDP + RT for LA-HNSCC between July 2006 and October 2022. LA-HNSCC includes cancer in the oropharynx, hypopharynx, or larynx with a clinical stage of 3 or 4 without distant metastases based on the Union for International Cancer Control staging system 8th edition. The radiation dose of 70 Gy was delivered in 35 fractions by 3-dimensional conformal radiotherapy, intensity-modulated radiotherapy, or proton beam therapy. The primary endpoint was the 3-year overall survival (OS), and the secondary endpoints were the 3-year progression-free survival (PFS) and 3-year cause-specific survival (CSS). The Kaplan–Meier method was used to calculate survival rates, and the log-rank test was used to evaluate statistical significance. A Cox proportional hazards model was used for the multivariate analysis of prognostic factors. Results: The median age of the 49 patients was 72 (range: 70–78) years. The median CDDP dose was 200 (40–280) mg/ m², and 47 patients completed scheduled radiotherapy. Forty-eight patients (98.0%) had a performance status of ≥ 1 at the initial visit. The 3-year OS, PFS, and CSS were 80.9% (95% confidence interval [CI]: 64.8–90.7), 58.9% (95%CI: 42.7–73.3), and 85.0% (95%CI: 68.7–93.4), respectively. In the multivariate analysis, the cumulative CDDP dose (< 200 or ≥ 200 mg/m²) was a significant factor for OS (hazard ratio: 0.29 [95% CI 0.08–0.97], p = 0.044). There was one case of early mortality. Grade 3 or higher late adverse events were observed in four patients (8.2%). Conclusions: Weekly CDDP + RT in older patients led to good survival outcomes with an acceptable rate of adverse events. CDDP should be administered at a dose of at least 200 mg/m² in older patients. Trial registration Retrospectively registered

Objectives: In a previous study of hepatic toxicity, the following three factors were identified to predict the benefits of proton beam therapy (PBT) for hepatocellular carcinomas (HCCs) with a maximum diameter of ≤5 cm and Child-pugh grade A (CP-A): number of tumors (1 vs ≥2), the location of tumors (hepatic hilum or others), and the sum of the diameters of lesions. The aim of this study is to analyze the association between these three factors and hepatic toxicity. Methods: We retrospectively reviewed patients of CP-A treated with PBT or photon stereotactic body radiotherapy (X-ray radiotherapy, XRT) for HCC ≤5 cm. For normal liver dose, the V5, V10, V20 (volumes receiving 5, 10, and 20 Gy at least), and the mean dose was evaluated. The albumin-bilirubin (ALBI) and CP score changes from the baseline were evaluated at 3 and 6 months after treatment. Results: In 89 patients (XRT: 48, PBT: 41), those with two or three (2–3) predictive factors were higher normal liver doses than with zero or one (0–1) factor. In the PBT group, the ALBI score worsened more in patients with 2–3 factors than those with 0–1 factor, at 3 months (median: 0.26 vs 0.02, p = 0.032) and at 6 months (median: 0.35 vs 0.10, p = 0.009). The ALBI score change in the XRT group and CP score change in either modality were not significantly different in the number of predictive factors. Conclusion: The predictive factor numbers predicted the ALBI score change in PBT but not in XRT. Advances in knowledge: This study suggest that the number of predictive factors previously identified (0–1 vs 2–3) were significantly associated with dosimetric parameters of the normal liver in both modalities. In the proton group, the number of predictive factors was associated with a worsening ALBI score at 3 and 6 months, but these associations were not found in the photon SBRT group.

Background/Objectives: The severity of radiation-induced toxicity in head and neck cancer (HNC) radiotherapy should be predicted for the prognosis of the patient’s quality of life. Multiple organs at risk (OARs) are susceptible to toxicity in the head and neck. Hence, we aimed to investigate the feasibility of evaluating radiation-induced xerostomia and dysphagia based on multi-OAR dosiomics in HNC radiotherapy. Methods: We used radiotherapy treatment planning and toxicity data collected from 44 patients with HNC. High- and low-toxicity grades were classified using dosiomic models derived from multiple OARs. Dosiomic features were computed from the planned dose distribution per OAR. A prediction model was derived using selected dosiomic features and toxicity grades based on extreme gradient boosting for every OAR and all OARs. The model performance was evaluated in terms of the area under the curve (AUC) from leave-one-out cross-validation. Models based on dose volume histogram features and combining these with dosiomic features were derived to compare the prediction performance per OAR. Performance comparisons across OARs were also conducted. Results: The prediction models with the highest AUCs for xerostomia and dysphagia were the dosiomic model using all OARs, with an AUC of 0.843 (95% confidence interval—CI, 0.725–0.961), and that using the middle pharyngeal constrictor muscle, with an AUC of 0.878 (95% CI, 0.772–0.984). Conclusions: The evaluation results demonstrated the feasibility and potential of predicting radiation-induced toxicities based on multi-OAR dosiomics in HNC radiotherapy. Further investigations are required to determine the generalizability of our findings.

Objectives: We aimed to investigate whether daily computed tomography (CT) images could predict the daily gastroduodenal, small intestine, and large intestine doses of stereotactic body radiation therapy (SBRT) for pancreatic cancer based on the shortest distance between the gross tumor volume (GTV) and gastrointestinal (GI) tract. Methods: Twelve patients with pancreatic cancer received SBRT of 40 Gy in five fractions. We recalculated the reference clinical SBRT plan (PLAN_ref) using daily CT images and calculated the shortest distance from the GTV to each GI tract. The maximum dose delivered to 0.5 cc (D_0.5cc) was evaluated for each planning at-risk volume of the GI tract. Spearman’s correlation test was used to determine the association between the daily change in the shortest distance (Δshortest distance) and the ratio of ΔD_0.5cc dose to D_0.5cc dose in PLAN_ref (ΔD_0.5cc/PLAN_ref) for quantitative analysis. Results: The median shortest distance in PLAN_ref was 0 mm in the gastroduodenum (interquartile range, 0–2.7), 16.7 mm in the small intestine (10.0–23.7), and 16.7 mm in the large intestine (8.3–28.1 mm). The D_0.5cc of PLAN_ref in the gastroduodenum was >30 Gy in all patients, with 10 (83.3%) having the highest dose. A significant association was found between the Δshortest distance and ΔD_0.5cc/ PLAN_ref in the small or large intestine (p < 0.001) but not in the gastroduodenum (p = 0.404). Conclusions: The gastroduodenum had a higher D_0.5cc and predicting the daily dose was difficult. Daily dose calculations of the GI tract are recommended for safe SBRT. Advances in knowledge: This study aimed to predict the daily doses in SBRT for pancreatic cancer from the shortest distance between the GTV and the gastrointestinal tract. Daily changes in the shortest distance can predict the daily dose to the small or large intestines, but not to the gastroduodenum.