Long Term Follow-up of Prostate Cancer Patients Who Fail Salvage Radiation Therapy and Radical Prostatectomy
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PURPOSE/OBJECTIVES: Salvage radiation therapy (SRT) is an effective treatment for prostate cancer (PCa) that has recurred after radical prostatectomy. Long term follow up in men who developed biochemical recurrence (BCR) after SRT is less well described in literature. This study follows the natural history of patients treated with SRT > 13 years ago. MATERIALS/METHODS: 61 patients with PCa treated with SRT during 1992-2000 at UT Southwestern were identified. Survival was calculated using the Kaplan-Meier method. Log-rank test and Cox regression were used to determine significance of clinical parameters with outcome. RESULTS: Median follow-up for the 61 patients was 126 months (3-238). Median age at SRT was 62 (46-83), 15% of patients had pathologic Gleason score (pGS) 8-10 disease, 14% had pre-surgical PSA > 20, 63% had pT3+ disease, 59% had positive margin at time of surgery. Of 61 patients, 34 (56%) had treatment failure after SRT. 5 y and 10 y freedom from PSA failure (FFPF) were 51% and 33% respectively. pGS significantly correlated with FFPF (p=.0042) and overall survival (OS) (p=.0022). Seminal vesicle invasion (p=.0357, HR 2.07, 1.0-4.2), lymphovascular invasion (p=.035, HR 5.28, 0.9-32.2), and pre-SRT PSA (p=.015, HR 2.27, 1.14-4.5) were associated with decreased FFPF. For the 34 patients who had BCR, median follow-up was 157.5 months (13-238). Median time to BCR following SRT was 30 months (3-138). 19 (56%) received androgen deprivation therapy (ADT). Median time from BCR to initiating ADT was 48 months (0-151). Outcome after BCR is as follows. OS at 5 and 10 y were 79% and 59% (median 13.6 y). PCa-specific survival (PCSS) at 5 and 10 y were 89% and 73%. Distant metastasis free survival at 5 and 10 y were 75%. Castration resistant free survival at 5 and 10 y were 81% and 70%. Time to BCR after SRT < 1 year (p=.0005, HR 3.92, 2.7-33.6) and < 2 years (p=.021, HR 2.52, 1.2-9.2) significantly correlated with decreased OS, compared to < 3 years (p=.054) and < 5 years (p=.073). CONCLUSIONS: Clinical parameters predictive of treatment failure after SRT are presented. Unfortunately, 25% of patients who fail SRT developed distant metastases within 5 yrs of failure. 56% of those who failed eventually also required ADT. Such events could have significant emotional impact, affect quality of life, and lead to morbidity related to salvage therapy. However, while up to 27% of patients died from PCa after BCR at 10 years, only patients who failed SRT in less than 2 years had a significantly worse OS. Overall, patients who fail SRT treatment can have a prolonged median overall survival of 13.6 years.