Toxicity and risk factors after combined high-dose-rate brachytherapy and external beam radiation therapy in men ≥75 years with localized prostate cancer.

PURPOSE: Combined high-dose-rate brachytherapy (HDR-BT) and external beam radiation therapy (EBRT) is a favorable treatment option in non-metastatic prostate cancer. However, reports on toxicity and outcome have mainly focused on younger patients. We aimed to determine toxicity and biochemical control rates after combined HDR-BT and EBRT in men ≥75 years. METHODS: From 1999 to 2015, 134 patients aged ≥75 years (median 76 years; 75-82 years) were identified. Patients received 18 Gy of HDR-BT (9 Gy/fraction on days 1 and 8) with an iridium-192 source. After 1 week, supplemental EBRT with a target dose of 50.4 Gy was started (delivered in 1.8 Gy fractions). RESULTS: Median follow-up time was 25 months (0-127 months). No severe (grade 4) gastrointestinal (GIT) or genitourinary (GUT) toxicities were observed. In 76 patients (56.7%), 3D conformal radiation therapy (CRT) and in 34.3% intensity-modulated radiotherapy (IMRT) was applied. CRT-treated patients were at a 2.17-times higher risk (hazard ratio [HR]: 2.17, 95% confidence interval [CI]: 1.31-3.57, p = 0.002) of experiencing GUT. GIT risks could be reduced by 78% using IMRT (HR: 0.22, 95% CI: 0.07-0.75, p = 0.015). Patients with a higher T stage (T2c-3a/b) were less likely to experience GIT or GUT (HR: 0.49, 95% CI: 0.29-0.85, p = 0.011 and HR: 0.5, 95% CI: 0.3-0.81, p = 0.005, respectively). CONCLUSION: HDR-BT/EBRT is a well-tolerated treatment option for elderly men ≥75 years with a limited number of comorbidities and localized intermediate- or high-risk prostate cancer. IMRT should be favored since side effects were significantly reduced in IMRT-treated patients.

Validation of the current eligibility criteria for focal therapy in men with localized prostate cancer and the role of MRI.

PURPOSE: To validate current eligibility criteria for focal therapy (FT) in prostate cancer men undergoing radical prostatectomy (RP) and to assess the role of magnetic resonance imaging (MRI). METHODS: Retrospective analysis of 217 RP patients (2009-2016) with preoperative MRI (almost all in external institutions) and fulfillment of different FT eligibility criteria: unilateral tumor, clinical tumor stage ≤ cT2a, prostate volume ≤ 60 mL and either biopsy Gleason 3 + 3 or ≤ 3 + 4 and PSA ≤ 10 or ≤ 15 ng/mL. Multivariable logistic regression analyses (MVA) assessed the role of MRI to predict the presence of significant contralateral tumor or extracapsular extension (ECE), including seminal vesicle invasion. To quantify model accuracy, Receiver Operating Characteristics-derived area under the curve (AUC) was used. RESULTS: Of 217 patients fulfilling widest biopsy criteria and 113 fulfilling additional MRI criteria, 64 (29.7%) and 37 (32.7%) remained eligible for FT according to histopathological results. In MVA, fulfillment of MRI criteria reached independent predictor status for prediction of contralateral tumor but not for ECE. Addition of MRI resulted in AUC gain (57.5-64.6%). Sensitivity, specificity, PPV and NPV for MRI to predict contralateral tumor were: 41.8, 71.6, 70.9 and 42.6%, respectively. Virtually the same results were recorded for Gleason 3 + 3 and/or PSA ≤ 10 ng/mL. CONCLUSIONS: Patient eligibility criteria for FT using biopsy criteria remained insufficient with respect to contralateral tumor disease. Although, MRI improves accuracy, it cannot safely exclude or minimize chance of significant cancer on contralateral prostate side. To date, stricter eligibility criteria are needed to provide more diagnostic reliability.