Genitourinary Cancer

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SU_32_2329 - Adjuvant Radioation Therapy Versus Early Salvage Radiation Therapy in pT3 or Margin-Positive Prostate Cancer: A Meta-Analysis of Matched-Control Studies

Sunday, October 21
1:15 PM - 2:45 PM
Location: Innovation Hub, Exhibit Hall 3

Adjuvant Radioation Therapy Versus Early Salvage Radiation Therapy in pT3 or Margin-Positive Prostate Cancer: A Meta-Analysis of Matched-Control Studies
M. P. Shaikh Jr1, F. Alite Jr2, V. Bakalov3, T. Altoos4, M. J. Wu5, and G. M. Jacobson6; 1West Virginia University, Morgantown, WV, 2Geisinger Medical Center, Danville, PA, 3Allegany General Hospital, Pittsburgh, PA, 4Pinellas Radiation Oncology Associates, Clearwater, FL, 5Loyola University Chicago, Chicago, IL, 6Department of Radiation Oncology, West Virginia University, Morgantown, WV

Purpose/Objective(s): Conduct a meta-analysis of the available retrospective match-control literature comparing adjuvant radiotherapy (ART) to early salvage radiotherapy (ESRT) strategy in pathologic T3 or margin-positive prostate cancer.

Materials/Methods: A comprehensive MEDLINE, clinicaltrials.gov, and Cochrane Library search for matched-pair studies of ART vs ESRT was performed. Studies including patients with pT3 or margin-positive, node-negative disease, post-prostatectomy that compared outcomes of ART vs ESRT. Studies included, defined undetectable PSA as <0.10 ng/mL or below the sensitivity of assay. ESRT was defined as salvage radiotherapy delivered at PSA recurrence to 0.1 ng/mL or higher, but less than or equal to 0.5 ng/mL. Post-RT biochemical failure was defined as PSA rise to 0.2 ng/mL or first rise above 0.2 ng/mL if post-RT nadir was greater than 0.2 ng/mL. Results were synthesized for biochemical progression-free (BPFS), metastasis-free (MFS), overall survival (OS), freedom from androgen depravation therapy (FFADT) and prostate cancer-specific survival (PCSS). When hazard ratios (HR) were not provided, Parmar (1998) method was used and proportional hazard was assumed. Either random-effects model (RE) or fixed-effect model (FE) were used based on the test of heterogeneity. A proportion of patients who receive ART would have been cured with prostatectomy alone, we performed a sensitivity analysis to estimate proportion who need to be cured with prostatectomy alone for BPFS benefit of ART to lose statistical significance over ESRT.

Results: Three retrospective match-control studies (Buscariollo et al, Hwang et al & Ost et al) were identified with 1106 patients (ART n=553, ESRT n=553). All studies reported on BPFS. Pooled analysis showed that ART resulted in greater BPFS (HR = 0.46; 95% CI: 0.37, 0.57; P < 0.00001, FE). Two studies reported on MFS and OS. Synthesis of data showed that ART improved MFS (HR = 0.45; 95% CI: 0.26, 0.75; P = 0.003, FE) as well as OS (HR = 0.57; 95% CI: 0.35, 0.92; P = 0.02, FE) compared with ESRT. One article reported on FFADT, which was significantly improved with ART (HR = 0.28; 95% CI: 0.15, 0.52; P < 0.00001, FE). One article reported on PCSS, which showed trend in favor of ART (HR = 0.16; 95% CI: 0.02, 1.36; P < 0.09, FE). A sensitivity analysis estimated that surgery alone would have to achieve freedom from biochemical recurrence in > 52% of the patients at 10 years before BPFS benefit of ART over ESRT would lose statistical significance. For comparison BPFS was achieved in only 26-41% of the patients at 10 years in the wait-and-see arms of the three adjuvant randomized trials (EORTC, SWOG, ARO96-02).

Conclusion: BPFS, MFS, FFADT and OS were significantly improved with ART compared to ESRT. These findings support use of ART as a preferred treatment strategy in pathologic T3, margin positive patients.

Author Disclosure: M.P. Shaikh: None. F. Alite: None. V. Bakalov: None. T. Altoos: None. M. Wu: None. G.M. Jacobson: Oncology Steering Committee member; HVO health Volunteers Overseas.

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SU_32_2329 - Adjuvant Radioation Therapy Versus Early Salvage Radiation Therapy in pT3 or Margin-Positive Prostate Cancer: A Meta-Analysis of Matched-Control Studies



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