Time to biochemical relapse after radical prostatectomy and efficacy of salvage radiotherapy in patients with prostate cancer.

ABSTRACT

BACKGROUND: To investigate the prognostic and therapeutic implications of time to biochemical relapse (BCR) in patients with prostate cancer after radical prostatectomy. METHODS: The records of 3210 consecutive men with prostate cancer who underwent radical prostatectomy between January 1998 and June 2013 were retrospectively reviewed. Patients with BCR were divided into three groups based on quartiles of time to BCR, namely an early group (first quartile), an intermediate group (second and third quartiles) and late group (fourth quartile). RESULTS: 817 (25.5%) patients experienced BCR at a median of 24.9 months after surgery. The 8-year rate of distant metastasis-free survival (64.3% vs. 41.3%, p = 0.002) and cancer-specific survival (86.6% vs. 63.4%, p < 0.001) was higher in the salvage radiotherapy (SRT) group than the androgen deprivation therapy (ADT) group in patients with early BCR, whereas those rates (91.3% vs. 87.9%, p = 0.607 and 100.0% vs. 93.1%, p = 0.144, respectively) were similar in patients with late BCR. In the intermediate BCR group, the impact of SRT over ADT on 8-year cancer-specific survival was modest (91.9% vs. 82.3%, p = 0.057) and was limited to patients with pT2 or pT3a disease. CONCLUSIONS: SRT may decrease the risk of distant metastasis and cancer-specific mortality in patients with early BCR. However, a survival benefit for those with late BCR was not apparent. For patients with intermediate BCR, SRT was associated with a cancer-specific survival benefit in patients with pT2 or pT3a disease. Novel genomic tests and imaging modalities may support clinical decision-making in these patients.