Comparative effectiveness of intensity modulated radiation therapy (IMRT), proton therapy (PT), and conformal radiation therapy (CRT) in the treatment of localized prostate cancer.

3 Background: Comparative effectiveness research is urgently needed in prostate cancer because of the rapid adoption of newer and costlier radiation treatments such as IMRT and PT despite limited demonstrated benefit compared to prior technologies. We compared the morbidity and disease control outcomes of IMRT, PT and the older CRT for primary prostate cancer treatment. Methods: Population-based study using Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data from 2000 through 2009 for patients with non-metastatic prostate cancer. Propensity score adjustment was used to balance demographic, disease and institutional characteristics. Rates of morbidity (gastrointestinal, urinary, erectile dysfunction, hip fractures) and additional cancer therapy (surrogate for recurrence) were calculated. Results: IMRT use increased from 0.15% in 2000 to 95.9% in 2008. In propensity score-adjusted analyses, men who received IMRT vs. CRT were less likely to be diagnosed with GI morbidity (13.4 vs. 14.7 per 100 person-years, p<0.001) and hip fractures (0.8 vs. 1.0, p=0.006), but more likely to be diagnosed with erectile dysfunction (5.9 vs. 5.3, p=0.006). IMRT patients were less likely to receive additional cancer therapy (2.5 vs. 3.1, p<0.001). In a propensity-score matched comparison between PT and IMRT, PT patients had a higher rate of GI morbidity (17.8 vs. 12.2 per 100 person-years, p<.001). No significant differences in rates of other morbidities or additional therapies between PT and IMRT. Conclusions: IMRT vs. CRT was associated with less GI morbidity and hip fractures, more erectile dysfunction, and less need for additional cancer therapy. This large-scale population-based study is the first to suggest a simultaneous reduction in disease recurrence and morbidity in patients treated with IMRT vs. CRT for localized prostate cancer. Proton therapy did not significantly improve outcomes compared to IMRT, but had increased GI morbidity. These results provide new and long-needed information to decision-makers regarding the currently available evidence on the comparative effectiveness of different RT techniques.

Duke Scholars

Author Bryce B. Reeve Population Health Sciences