Effects of Time to Treatment on Biochemical and Clinical Outcomes for Patients With Prostate Cancer Treated With Definitive Radiation

This is a retrospective study on the effects of time to treatment on outcomes for patients with prostate cancer treated with definitive radiotherapy. Subgroup analysis was done on men with high-risk disease treated without androgen deprivation therapy, as they were the group of patients who would most likely have detrimental effects from a relative long wait before definitive radiation. Introduction The purpose of this study was to evaluate if time to treatment (TTT) has an effect on outcomes for patients with localized prostate cancer treated with definitive external beam radiation therapy (EBRT). Patients and Methods We included 4064 patients (1549 low-risk, 1612 intermediate-risk, and 903 high-risk) treated with EBRT. For each National Comprehensive Cancer Network (NCCN) risk group, TTT (defined as the time between initial positive prostate biopsy and start of RT) was analyzed in 4 intervals: < 3, 3-6, 6-9, and 9-24 months. We recorded the use of androgen deprivation therapy among patients with intermediate-risk and high-risk disease. Results The median TTT was 3.3 months (range, 0.6-23.5 months), and it was similar for each risk group (range, 3.3-3.4 months). The median follow up was 64 months. There were no significant differences in biochemical failure, distant metastasis, or overall survival for patients with TTT < 3, 3-6, 6-9, or 9-24 months for each risk group. There were also no significant differences in the outcomes at 5 years when patients with TTT > 3.3 months were compared with those with TTT ≤ 3.3 months for each risk group. For high-risk men, 328 of 450 (72.9%) with TTT > 3.3 months were on androgen deprivation therapy (ADT) versus 299 of 453 (66%) with TTT ≤ 3.3 months. Among men with high-risk cancer treated without ADT, there remained no significant difference in outcomes between TTT > 3.3 months and TTT ≤ 3.3 months. Conclusion TTT was not associated with significant differences in outcomes among each risk group of men with localized prostate cancer treated with EBRT. Among the high-risk patients, there were no observed detriments in outcomes with TTT > 3.3 months regardless of androgen deprivation therapy use.