Background/Objectives: This study evaluated the efficacy and safety of salvage interstitial brachytherapy (S-ISBT) for isolated local recurrence (ILR) of cervical and endometrial carcinoma, stratifying patients by pelvic irradiation history (PIH). Methods: Patients with ILR treated with S-ISBT were retrospectively reviewed and categorized by initial treatment: Group A (surgery alone); Group B (surgery + postoperative radiotherapy (RT)); and Group C (definitive RT). Overall survival (OS), progression-free survival (PFS), local control (LC) rates, and the cumulative incidence functions (CIFs) for Grade ≥ 3 late adverse events (AEs) were estimated. Multivariate analysis identified prognostic factors. Results: The study included 70 patients (A: 28, B: 17, C: 25) with a median follow-up of 33.4 months. The 3-year OS, PFS, LC, and CIFs for Grade ≥ 3 late AEs for Groups A, B, and C were 80.8%, 66.7%, and 30.4% (p < 0.001); 56.4%, 41.5%, and 11.6% (p < 0.001); 89.1%, 61.4%, and 43.0% (p = 0.002); and 26.4%, 13.3%, and 32.0% (p = 0.40), respectively. Multivariate analysis suggested the type of PIH, disease-free interval, and tumor volume as independent prognostic factors. While no significant differences were observed between Groups A and B (OS: HR = 0.47, p = 0.19; PFS: HR = 0.60, p = 0.28), Group C exhibited a significantly higher risk than Group B (OS: HR = 3.08, p = 0.018; PFS: HR = 3.41, p = 0.004). Conclusions: S-ISBT could be considered for patients with prior postoperative RT, whose outcomes are significantly better than those with prior definitive RT.

To investigate the outcome of definitive proton beam therapy (PBT) for second primary non–small cell lung cancer after pneumonectomy. Between January 2006 and December 2019, 4 patients with second primary lung cancer occurring in the contralateral lung after pneumonectomy were selected from our database of patients who underwent PBT. All patients were men with a median age of 69 (range, 61-79) years at the time of PBT. The median time from pneumonectomy to PBT initiation was 104.5 (range, 92-117) months. All patients had a histology of squamous cell carcinoma and were inoperable due to poor respiratory function. The median survival time was 46.6 (range, 11.7-118.4) months; 3 patients died of their primary disease and one of bacterial pneumonia. The first relapses were local recurrence inside the irradiated field (n = 1) and outside the irradiated field (n = 2) and regional (n = 1). The median time to relapse was 21.5 (range, 6.6-48.1) months. Regarding adverse events, grade 2 pneumonitis occurred in 2 patients, but steroid administration was not required; no grade ≥3 pneumonitis was observed. Definitive PBT for new lesions in the residual lung after pneumonectomy was successful without serious adverse events, although the number of cases was small.