Use of high and very high dose radiotherapy after radical prostatectomy for prostate cancer in the United States

BACKGROUND: The cost-benefit tradeoff of radiation dose-intensification for prostate cancer in the post-prostatectomy setting is difficult to predict and is ideally studied in randomized trials. The purpose of this study was to assess the use of dose-escalated post-operative radiation (PORT) for prostate cancer in the United States, during a period in which there were no published level 1 studies on dose-escalation. METHODS: We performed analyses on pT2-3, N0, M0 prostate cancer patients who received PORT after an R0-1 resection within the National Cancer Data Base (NCDB), 2003–2012. We classified patients according to the use of high dose (>66.60 cGy) and very high dose (>70.20 cGy) radiation. We used regression analysis to assess the association of year of treatment with use of high and very high dose PORT. To demonstrate the potential of a registry-based network like the NCDB to prospectively monitor changes in radiation dosing patterns, we determined the year in which a significant change in dose could have been first detected had dose been actively monitored. RESULTS: Between 2003 and 2012, the use of high dose PORT increased from 29.9% CI (26.7–33.1) to 63.5% CI (60.6–66.5) and very high dose PORT from 4.5% CI (3.1–5.9) to 10.8% CI (8.9–12.6) (adjusted p < 0.01, for both trends). Patients diagnosed at community centers were less likely to be treated with high dose PORT compared to those at academic or comprehensive centers (p < 0.01 for both comparisons). Had the NCDB network been prospectively monitoring PORT dose, significant increases in dose would have been detected as early as 2004 and after every year of the study period. CONCLUSIONS: The use of both high dose and very high dose PORT increased two-fold from 2003 to 2012 in the absence of randomized studies. This change in practice may be exposing patients to excess toxicity without cancer control benefits. Monitoring dosing patterns using cancer registries is feasible.