The Efficacy and Safety of a Low Relative Dose Intensity of Cabazitaxel in Patients With Metastatic Castration-resistant Prostate Cancer.

BACKGROUND/AIM: Clinical trials have shown that the efficacy of a reduced dose of cabazitaxel (20 mg/m2 every 3 weeks) was not inferior to that of the standard dose (25 mg/m2 every 3 weeks). However, the efficacy of even lower relative dose intensities, such as 20 mg/m2 every 4 weeks, have not been evaluated conclusively. The aim of this study was to investigate the efficacy and safety of a low relative dose intensity of cabazitaxel in patients with metastatic castration-resistant prostate cancer in the real world. PATIENTS AND METHODS: We retrospectively analyzed 101 consecutive patients treated with cabazitaxel for docetaxel-refractory metastatic castration-resistant prostate cancer. The progression-free and overall survival after introduction of cabazitaxel and prostate-specific antigen response rate were assessed as oncological outcome measures. RESULTS: The patients were divided into two groups (relative dose intensity >60%, n=74 and ≤60%, n=27). Both progression-free and overall survivals were significantly better in the >60% group than in the ≤60% group (median 5 and 2 months, p<0.01, and 15 and 6 months, p<0.01, respectively). In multivariate analyses, visceral metastasis and relative dose intensity ≤60% were prognostic factors for shorter progression-free and overall survivals (p=0.04, p<0.01, respectively). The incidence of adverse events was not significantly different between groups. CONCLUSION: The cabazitaxel relative dose intensity ≤60% group had significantly shorter progression-free and overall survivals than the >60% group, whereas the incidence of adverse events was not significantly different. The results suggested that reducing the relative dose intensity of cabazitaxel to ≤60% may not be recommended.

Treatment Results of High-dose-rate Brachytherapy and External Beam Radiation With Long-term Androgen Deprivation Therapy for Patients With Metastatic Prostate Cancer.

BACKGROUND/AIM: A recent clinical trial indicated the usefulness of local radiation therapy of the prostate in patients with low-volume metastatic prostate cancer. High-dose-rate brachytherapy (HDR-BT) is used mainly for high-risk, localized, and locally advanced cases. However, few studies exist on the efficacy of HDR-BT and external beam radiation therapy (EBRT) for metastatic prostate cancer. PATIENTS AND METHODS: We conducted a retrospective analysis of 39 patients diagnosed with regional lymph node metastasis and/or a limited number of metastases who underwent HDR-BT and EBRT with long-term androgen deprivation therapy. We utilized Cox's proportional hazards models to identify predictors of oncological outcomes. Treatment outcomes, including biochemical recurrence-free survival (BCRFS), clinical progression-free survival (CPFS), and castration-resistant prostate cancer-free survival (CRPCFS), were compared according to the clinical stage. RESULTS: The median follow-up duration was 49 months (range=23-136 months). The 5-year BCRFS, CPFS, CRPCFS, and cancer-specific survival rates were 62.2%, 67.2%, 83.2%, and 93.4%, respectively. Based on Kaplan-Meier analysis, N1M0 and N0-1M1b showed favorable outcomes compared with N1M1a. Multivariate analysis revealed that N1M1a prostate cancer was an independent risk factor for poor BCRFS, CPFS, and CRPCFS. CONCLUSION: HDR-BT and EBRT with androgen deprivation therapy is a feasible approach for patients with newly diagnosed regional and low-metastatic-burden prostate cancer. However, in our cohort M1a prostate cancer had significantly inferior outcomes. A well-controlled prospective study is imperative to confirm our results.