Long-term prognosis and prognostic factors of brachytherapy and propensity score matched comparisons of the outcomes between brachytherapy and radical prostatectomy: a retrospective cohort study

BACKGROUND: To report outcomes of patients undergoing brachytherapy (BT), investigate factors associated with biochemical progression-free survival (bPFS) and to compare its long-term prognosis with that of radical prostatectomy (RP) in localized prostate cancer. METHODS: The clinical data of 87 elderly patients with localized prostate cancer who underwent BT at Huadong Hospital affiliated to Fudan University from January 2009 to December 2016 were retrospectively analyzed. Patient prognoses and associated factors were investigated using univariate and multivariate Cox regression models. The clinical data of the 142 patients with localized prostate cancer who underwent RP during the same period were also collected. By using propensity score matching (PSM), the 42 patients who underwent BT were matched to 42 patients who underwent RP, and the differences in the survival curves were investigated using the Kaplan-Meier method. RESULTS: The median follow-up period of the patients who underwent BT was 101 months. The 5- and 10-year overall survival (OS) rates of the patients who underwent BT were 82.8% and 64.0%, respectively, while the 5- and 10-year bPFS rates were 97.2% and 87.5%, respectively. The preoperative clinical Tumor (T) stage was identified as a prognostic factor of bPFS, as patients who underwent BT whose clinical stage was T3 had a worse prognosis than those whose clinical stage was T1-T2 (HR =0.097, P=0.049). After PSM, the average follow-up time of the BT group was 90 months and that of the RP group was 94 months. No significant differences in bPFS or cause-specific survival were observed between the 2 groups. The OS of the RP group was significantly higher than that of the BP group (P=0.030). Among the patients with a prostate volume >35 mL, those who underwent BT had significantly higher pPFS than those who underwent RP (P=0.041). CONCLUSIONS: In the localized prostate cancer, BT and RP offered similar oncological control in the localized prostate cancer. Stage T3 prostate cancer who undergo BT was associated with worse biochemical failure and was the only variable significantly predictive of biochemical recurrence.