Post-operative radiation therapy for patients at high-risk of recurrence after radical prostatectomy: Does timing matter? - Abstract

OBJECTIVE: To evaluate among prostatectomy patients at high-risk of recurrence whether the timing of post-operative radiation therapy (adjuvant, early salvage with detectable post-prostatectomy PSA, or "late" salvage with PSA>1.0) significantly is associated with overall, prostate-cancer specific or metastasis-free survival, in a longitudinal cohort.

PATIENTS AND METHODS: Of 6176 prostatectomy patients in the Cancer of the Prostate Strategic Urologic Research Endeavor(CaPSURE), 305 patients with high-risk pathologic features(margin positivity, Gleason Score(pGS) 8-10, or pT3-T4) who underwent post-operative radiation were examined, either in the adjuvant(≤ 6 months from surgery with undetectable PSA, N=76) or salvage setting(>6 months after surgery or pre-radiation PSA>0.1, N=229). Early (PSA≤ 1.0, N=180) or late salvage radiation(PSA>1.0, N=49) was based on post-prostatectomy, pre-radiation PSA. Multivariable Cox regression examined associations with all-cause mortality and prostate cancer-specific mortality or metastases(PCSMM).

RESULTS: After a median of 74 months from prostatectomy, 65 men died(with 37 events of PCSMM). Adjuvant and salvage radiation patients had comparable high-risk features. Compared to adjuvant, salvage radiation(early or late) had an increased association with all-cause mortality(hazard ratio[HR] 2.7, p=0.018) and with PCSM(HR 4.0, p=0.015). PCSM-free survival differed by further stratification of timing, with 10-year estimates of 88%, 84%, and 71% for adjuvant, early salvage, and late salvage radiation, respectively(P=0.026). For PCSM- and overall-survival, compared to adjuvant RT, late salvage RT had statistically significantly increased risk, however early salvage RT did not.

CONCLUSION: This analysis suggests that patients who underwent early salvage radiation with PSA< 1.0 may have comparable metastasis-free and overall-survival compared with adjuvant RT; however, late salvage radiation with a PSA>1.0 is associated with worse clinical outcomes.

Written by:
Hsu CC, Paciorek AT, Cooperberg MR, Roach M 3rd, Hsu IC, Carroll PR.   Are you the author?
Department of Radiation Oncology, University of California at San Francisco.

Reference: BJU Int. 2015 Jan 20. Epub ahead of print.
doi: 10.1111/bju.13043

PubMed Abstract
PMID: 25600860 Prostate Cancer Section