Race Does Not Affect Tumor Control, Adverse Effects, or Quality of Life after Proton Therapy

Int J Part Ther. 2017 Spring;3(4):461-472. doi: 10.14338/IJPT-17-00006. Epub 2017 Jul 11.


Purpose: To compare 5-year biochemical control, toxicity, and patient-reported quality of life (QOL) outcomes for African American and White patients treated with proton therapy (PT) for prostate cancer.

Materials and methods: We reviewed the medical records of 1,066 men with clinically localized prostate cancer. Patients were treated with definitive PT between 2006 and 2010. Patients received a median radiation dose of 78 Gy (RBE) with conventional fractionation (1.8- 2 Gy [RBE] per fraction). Sixty-eight (6.4%) men self-identified as African American and 998 (93.6%) self-identified as White. Five-year rates of biochemical control, grade 3 genitourinary and gastrointestinal toxicity, and patient-reported QOL are reported and compared between African American and White patients.

Results: Median biochemical follow-up was 5.0 years for both African American and White patients. Median follow-up for toxicity was 5.0 and 5.2 years, respectively. On multivariate analysis, race was not a significant predictor for 5-year freedom from biochemical failure (HR 0.8, p=0.55). No significant association was found between race and grade 3 genitourinary toxicity on multivariate analysis at 5 years (HR 2.5, p=0.10). Patient-reported QOL using median EPIC bowel, urinary incontinence, and irritative summaries scores were not significantly different between the groups. African Americans had higher median sexual summary scores at 2 years than White patients (75 vs. 54, p=0.01) but by 5+ years, the sexual summary scores were no longer significantly different (63 vs. 53, p=0.35).

Conclusion: With a median follow-up of 5 years, there were no racial disparities in biochemical control, grade 3 toxicity, or patient-reported QOL after PT for prostate cancer.

Keywords: race disparity; prostate cancer; proton therapy; quality of life.