[Long-term oncologic outcomes of localized high-risk prostate cancer undergoing brachytherapy combined with external-beam radiation therapy and maximal androgen blockade].

ABSTRACT

Objective: To investigate the oncologic outcome and PSA kinetics of localized high-risk prostate cancer (PCa) patients treated with combination strategy of radiation therapy (RT) and maximal androgen blockade (MAB). Methods: We retrospectively reviewed the clinical data of 320 localized PCa patients undergoing RT+ MAB from 2001 to 2015. And radiation treatment protocol consisted of permanent prostate brachytherapy (PPB) at 110 Gy and EBRT at 45 Gy/23 fractions. Results: The median follow-up time was 90 (range 12-186) months. And 117 (36.6%) cases underwent MAB + external-beam radiotherapy (EBRT), and other 203 (63.4%) cases received MAB+ EBRT+ PPB. Multivariate Cox regression analyses showed that PSA kinetics were positive indicators of oncologic outcomes. Furthermore, PSA kinetics were aberrantly improved by supplemental PPB to MAB+ EBRT as following, PSA nadir (1.3±0.7)µg/L vs(0.11±0.06)µg/L, time of PSA decrease to nadir (7.5±1.8)months vs (3.2±2.1)months, PSA doubling time (15.6±4.2)months vs (22.6±6.1)months, PSA decreasing amplitude (84.6±6.2)%vs(95.8±3.4)%. Additionally, the median time of several important oncologic events in MAB+ EBRT+ PPB group were also prolonged than that in MAB+ EBRT group as following, overall survival (12.3 years vs 9.1 years, P<0.001), biochemical recurrence-free survival (9.8 years vs 6.5 years, P<0.001), skeletal-related event (10.4years vs 8.2 years, P<0.001), and cytotoxic chemotherapy (11.6 years vs 8.8 years, P=0.007). Conclusion: MAB+ EBRT+ PPB is extremely effective combination strategy for localized high-risk PCa patients, and PPB plays the important synergistic role in improving PSA kinetics, which are independent predictor for oncologic outcomes.