AB116. Research of efficacy of brachytherapy for localized prostate cancer

OBJECTIVE To investigate the efficacy of brachytherapy for patients with localized prostate cancer and the influence factors. METHODS There were 61 patients with localized prostate cancer were treated with brachytherapy between April 2001 and March 2011 in Department of Urology, Peking University First Hospital, including 11 patients who received combined external beam radiotherapy. The mean age was 75.2 years (range 57-84 years). Clinical stage was T1c in 12 patients, T2a in 18 patients, T2b in 17 patients, and T2c in 14 patients. Long-term follow-up was carried on all patients for prostate specific antigen (PSA) and adverse effects. Kaplan-Meier survival curves, Log-rank test and univariate Cox proportional hazard regression analysis was used to examine the factors associated with the treatment efficacy. RESULTS The median follow-up was 49 months (range 9-126 months). The mean PSA before treatment and the mean nadir PSA after operation were (17.80 ± 14.44) µg/L and (1.16 ± 1.15) µg/L, respectively. The PSA of 58 patients (95.1%) reached a nadir < 4.0 µg/L, which was even < 1.0 µg/L in 37 patients (60.7%). The mean time to reach the nadir PSA was 11.6 months after operation. The short-term adverse events after operation included fever in 4 patients, hematuria in 7 patients, and hematochezia in 4 patients. The most common long-term adverse event was urinary irritation (31.1%); other long-term adverse events were rare, including hematochezia, hematuria, urinary incontinence, urinary retention, mild diarrhea and radiation enteritis. The estimated mean biochemical recurrence-free survival after brachytherapy was 41.0 months (95% CI: 31.05-50.94 months). The mean nadir PSA after operation were 1.32 µg/L in the 11 patients who received combined external beam radiotherapy, and their estimated mean biochemical recurrence-free survival was 38 months. Patients with nadir PSA < 1.0 µg/L had a significant longer biochemical recurrence-free survival than those with nadir PSA between 1.0 µg/L and 4.0 µg/L (42.9 vs. 32.0 months, χ² = 4.445, P = 0.035). CONCLUSIONS Brachytherapy is an effective treatment strategy for localized prostate cancer, with relatively low rate of severe adverse events. After brachytherapy, a nadir PSA < 1.0 µg/L might indicate a better prognosis.