Post-Prostatectomy Radiation with Long Term Follow-up: Outcomes and Changing Indications.
Ghali Lemtiri-Chlieh, MS, Alex Hennessey, MD, Ilene Staff, PhD, Peter Haddock, PhD, Max Jackson, BS, Joseph Tortora, MS, Alison Champagne, BA, Joseph Cusano, BS, Tara McLaughlin, PhD, Joseph Wagner, MD.
Hartford Hospital, Hartford, CT, USA.
BACKGROUND: The criteria for adjuvant and salvage post-prostatectomy radiotherapy (ART and SRT, respectively) continue to be debated. While ASTRO/AUA guidelines recommend considering ART for patients with adverse pathologic findings, preliminary data from the RADICALS trial suggest that rates of biochemical progression-free survival do not differ between ART and early SRT. We examined the incidence of post-prostatectomy radiotherapy (RT) and the rate of secondary recurrences at our center to determine changing patterns in the administration of post prostatectomy radiation and outcomes.METHODS: We retrospectively identified patients who underwent radical prostatectomy (RP) and subsequent SRT or ART between Dec 1, 2003-Dec 31, 2013. Demographic, clinical, and pathological features were extracted. Patient groups were defined as either (i) ART: PSA <0.2 ng/mL, treatment within 1 year post-RP, stable PSA, (ii) Early SRT: rising PSA <0.2 ng/mL or (iii) Traditional SRT: PSA ≥0.2 ng/mL prior to RT. Secondary recurrence was defined as a confirmed PSA ≥0.2 ng/mL and above the post radiation nadir. The incidence and time to secondary recurrence, metastatic disease, and prostate cancer specific mortality were compared among the RT treatment groups. RESULTS: 3,570 patients underwent RP; 209 patients (5.9%) received post-RP RT. Of these 39 (18.7%), 29 (13.9%) and 141 (67.5%) underwent ART, early SRT and traditional SRT, respectively. Eight (20.5%), 4 (13.8%), and 40 (28.4%) of ART, early SRT, and traditional SRT groups received concurrent androgen deprivation therapy (p ns). Median time (in years) between surgery and last PSA was 7.06, with an interquartile range of 5.17- 10.24. The incidence of ART and early SRT significantly increased from 2003-2007 to 2008-2013 (increasing from 8.6% to 25.0% and from 3.7% to 20.3%, respectively; p<0.001). Outcome results are presented in Table 1. Overall, the groups differed significantly in rates of secondary recurrences (p=0.037). These differences remained significant in multivariate analyses accounting for stage, PSA and Gleason Grade Group (p=0.026). Similarly, multivariate analysis indicated that rates of metastasis differed significantly between the groups (p=0.033) as did recurrence free survival when controlling for the same variables (p=.021). No differences were observed in prostate cancer specific mortality. CONCLUSIONS: In accordance with ASTRO/AUA guidelines and results from studies like RADICALS, adjuvant RT and early SRT are being given with increased frequency at our institution. We feel the advent of hypersensitive PSA has contributed to the increased use of early SRT. According to ASTRO/AUA guidelines, “data from retrospective and prospective trials tend to support the notion that more favorable biochemical outcomes are associated with very low PSA values at the time RT is offered.” Consistent with this premise, our secondary recurrence rate for early SRT (37.9%) was lower than traditional SRT (51.1%) but this was not significant. The impact and outcomes of changing post prostatectomy radiation treatment deserves further study. 
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