Radical prostatectomy and radiation therapy are associated with similar overall survival among men with localized prostate cancer (PCa), but progression-free survival rates are better with radiation therapy, Japanese researchers reported at the 2015 European Cancer Congress in Vienna.

Narihiko Hayashi, MD, and colleagues at Yokohama City University School of Medicine, studied 1,413 patients with clinically localized PCa treated at their institution. The group included 362 radical prostatectomy (RP) patients, 225 who had intensity-modulated radiation therapy (IMRT) and 826 who had brachytherapy (BT). The investigators classified patients as having low-, intermediate-, and higher-risk disease according to National Comprehensive Cancer Network criteria.

The median follow-up periods for the RP, IMRT, and BT patients were 69, 51, and 57 months, respectively. For the study population as a whole, the 7-year rates of overall survival were 96.3%, 94.1%, and 98.1%, respectively, and the 7-year rates of progression-free survival (PFS) were 61.6%, 96.5%, and 90.7%, respectively.

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In Kaplan-Meier analyses, 5- and 7-year overall survival rates did not differ significantly between RP and the radiation treatments, but 5- and 7-year PFS rates were significantly higher with IMRT and BT.

The researchers also performed Kaplan-Meier analysis using propensity score matching to reduce treatment selection bias. For RP versus IMRT, each cohort included 130 patients; for RP versus BT, each cohort included 214 patients. For the RP versus IMRT analyses, the biochemical failure-free survival rates were significantly higher for patients with low-, intermediate-, and high-risk disease. For the RP versus BT analyses, the rates were significantly higher with BT among patients with low- and intermediate-risk disease, but did not differ significantly among patients with high-risk disease.

The researchers defined radiotherapy biochemical failure as a nadir PSA level plus 2 ng/mL and RP biochemical failure as a PSA level greater than 0.2 ng/mL.