Low-dose-rate brachytherapy for prostate cancer: outcomes at >10 years of follow-up.

OBJECTIVE: To examine biochemical control, survival, and late morbidity with definitive low-dose-rate brachytherapy (LDR-BT) for patients with prostate cancer surviving for >10 years after treatment. PATIENTS AND METHODS: We identified 757 men with localised prostate cancer who underwent definitive LDR-BT in the period 1990-2006 and were followed for >10 years at our institution. Biochemical failure-free survival (BFFS), distant metastases-free survival (DMFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were selected as study endpoints. Survival was examined using the log-rank test, Kaplan-Meier method, and Cox regression modelling. Urinary, quality of life (QoL), and potency scores at baseline and last follow-up were recorded. RESULTS: The median follow-up was 12.5 years (range, 10.1-21.8 years). At the time of analysis, 88.6% of patients were alive, 1.5% died from prostate cancer and 13.9% developed biochemical failure, with 82% of failures occurring in the first decade of follow-up. Overall, 2.3% developed distant metastases. On multivariate analyses, stage T3a-T3b, prostate-specific antigen level of >20 ng/mL, intermediate- and high-risk disease predicted worse BFFS; whereas age >70 years at diagnosis and stage T3a-T3b predicted worse OS. A total biologically effective dose of ≥150 Gy and androgen-deprivation therapy were associated with improved BFFS, but not OS. The overall 17-year rates for BFFS, DMFS, PCSS, and OS were 79, 97, 97, and 72%, respectively. Respective 17-year BFFS rates for low-, intermediate- and high-risk patients were 86, 80, and 65% (P < 0.001), whereas OS rates for the same groups were 82, 73, and 60%, respectively (P = 0.09). Amongst those patients who were potent at baseline, 25% remained potent at the last follow-up. Urinary function and QoL were mainly unaffected. CONCLUSIONS: LDR-BT yields excellent survival rates, with a 17-year PCSS rate of 97%. In all, 18% of patients with biochemical relapse failed at >10 years after implantation, which justifies their continued follow-up.

Dosimetric Correlates of Pulmonary Toxicity in Patients with Malignant Pleural Mesothelioma Receiving Radiation Therapy to the Intact Lungs.

PURPOSE: We aimed to determine dose-volume constraints that correlate with severe (grade ≥3) radiation pneumonitis (RP) in patients diagnosed with malignant pleural mesothelioma, treated using volumetric modulated arc therapy. METHODS AND MATERIALS: Data from 40 patients with malignant pleural mesothelioma who underwent pleurectomy decortication and adjuvant radiation therapy at our institution between December 2010 and October 2016 were retrospectively analyzed. Dosimetric variables for the absolute volume and percentage volume of the ipsilateral lung, contralateral lung, and heart were recorded. Events of RP were assessed using the Common Terminology Criteria for Toxicity and Adverse Events, version 4.0. The statistical analysis with Wilcoxon rank-sum, Spearman rank correlation, and receiver operating characteristic curves was computed using MATLAB V9.1, RV3.4, and SAS V9.4. RESULTS: Of the 40 patients, 26 patients (65%) were male. The median age at the time of diagnosis was 66.5 years (range, 44-84 years). The median prescription dose was 45 Gy (range, 30-54 Gy). Five patients (12.5%) had grade ≥3 RP. The incidence of grade≥ 3 RP showed a significant correlation (P < .05) with the absolute volume and percentage volume of the ipsilateral lung spared of ≥20 Gy (55 cc; 7%) and spared of ≥30 Gy (200 cc; 23%). Dosimetric variables of the contralateral lung, total lung, and heart did not show a correlation with incidence of grade ≥3 RP. CONCLUSIONS: In our cohort, sparing the ipsilateral lung of at least 55 cc of 20 Gy and 200 cc of 30 Gy correlated with a reduced incidence of severe (grade ≥3) RP.