Long-term oncologic outcomes of postoperative adjuvant versus salvage radiotherapy in prostate cancer: Systemic review and meta-analysis of 5-year and 10-year follow-up data

Postoperative radiotherapy for prostate cancer: the sooner the better and potential to reduce toxicity even further

PURPOSE

To evaluate biochemical relapse-free survival (bRFS), overall survival (OS), late rectal and bladder toxicities in a retrospective single institution series, also applying an in-house software for biological dose calculation.

METHODS

258 patients submitted to radiotherapy after prostatectomy were considered. Differences between groups were calculated using the log-rank test and the relevant clinical and therapeutic variables were considered for multivariate analysis. PRODVH is an in-house system able to calculate mean dose-volume histograms (DVHs) of a series of patients, to convert them in biologically effective DVHs (BEDVHs) and allowing to compare them with ANOVA and t Student test.

RESULTS

Adjuvant radiotherapy (ART) and salvage radiotherapy (SRT) were performed in 131 (50.8%) and 127 patients (49.2%). At multivariate analysis advanced T stage, androgen deprivation total (ADT) and SRT resulted as independent variables related to a worst bRFS (p = 0.019, 0.001 and 0.02), while GS > 7 and SRT affected negatively OS (p 0.047 and 0.039). High grade toxicity events occurred mainly in patients treated with 3-dimensional conformal radiotherapy (3DCRT) (proctitis p = 0.006; cystitis: p = 0.041). A significantly more favorable mean rectum BEDVH for patients with G0 or G1 rectal toxicity was shown (p < 0.001). Mean BEDVH for both bladder (p < 0.01) and rectum (p < 0.05) were also significantly better for volumetric modulated arc therapy-image guided radiotherapy (VMAT-IGRT) plans than for 3DCRT plans.

CONCLUSION

ART is better than SRT in terms of bRFS and OS, particularly for more aggressive cases, advanced T stage and higher Gleason Score. Postoperative prostate cancer radiotherapy should be applied as soon as possible after surgery. The use of modern techniques such as VMAT-IGRT significantly reduces toxicity.

Adjuvant versus salvage radiotherapy in prostate cancer: multi-institutional retrospective analysis of the Spanish RECAP database

PURPOSE

To compare adjuvant radiotherapy (ART) to salvage radiotherapy (SRT) after radical prostatectomy (RP) in a cohort of prostate cancer (PCa) patients. The primary aim was to comparatively assess 2- and 5-year biochemical relapse-free survival (BRFS). A secondary aim was to identify predictors of survival.

PATIENTS AND METHODS

Data were acquired from the RECAP database, a population-based prostate cancer registry in Spain. Inclusion criteria included RP (with or without lymphadenectomy) followed by ART or SRT. A total of 702 patients were analyzed. Pre-RT PSA values (>0.5 vs. ≤0.5 ng/ml), pathological stage (T1-2 vs. T3-4), post-surgical Gleason score (≤7 vs. 8-10), margin status (positive vs. negative), hormonal treatment (yes vs. no), and RT dose (≤66 Gy vs. >66 Gy) were evaluated to assess their impact on BRFS.

RESULTS

The mean patient age in the ART and SRT groups, respectively, was 64 years (range 42-82) and 64.8 years (range 42-82). Median follow-up after RT in the whole sample was 34 months (range 3-141). A total of 702 patients were included: 223 (31.8%) received ART and 479 (68.2%) SRT. BRFS rates (95% CI) in the ART and SRT groups at months 24 and 60 were, respectively: 98.1% (95.9-100.0%) vs. 91.2% (88.2-94.2%) and 84.5% (76.4-92.6%) vs. 74.0% (67.4-80.7%) (p = 0.004). No significant differences in OS were observed (p = 0.053). The following variables were significant predictors of biochemical recurrence in the SRT group: (1) positive surgical margin status (p = 0.049); (2) no hormonotherapy (p = 0.03); (3) total prostate dose ≤66 Gy (p = 0.004); and pre-RT PSA ≥0.5 ng/ml (p = 0.013).

CONCLUSIONS

This is the first nationwide study in Spain to evaluate a large cohort of PCa patients treated with RP followed by postoperative RT. ART yielded better 2- and 5-year BRFS rates, although OS was equivalent. These findings are consistent with most other published studies and support ART in patients with adverse prognostic characteristics after radical prostatectomy. Prospective trials are needed to compare immediate ART to early SRT to better determine their relative benefits.