Patient-reported long-term outcomes after conventional and high-dose combined proton and photon radiation for early prostate cancer.

contextIncreased radiation doses improve prostate cancer control but also increase toxicity to adjacent normal tissue. Proton radiation may attenuate adverse effects.

objectiveTo determine long-term, patient-reported, dose-related toxicity. DESIGN, SETTING, AND PATIENTS: We performed a post hoc cross-sectional survey of surviving participants in the Proton Radiation Oncology Group (PROG) 9509--a randomized trial comparing 70.2 Gy vs 79.2 Gy of combined photon and proton radiation for 393 men with clinically localized prostate cancer (stage T1b-T2b, prostate-specific antigen <15 ng/mL, and no radiographic evidence of metastasis). The estimated 10-year biochemical progression rate for patients receiving standard dose was 32% (95% confidence interval, 26%-39%) compared with 17% (95% confidence interval, 11%-23%) for patients receiving high dose (P < .001). We surveyed 280 of the surviving 337 patients (83%) from April 2007 to September 2008.

main outcome measuresProstate Cancer Symptom Indices, a validated measure of urinary incontinence, urinary obstruction and irritation, bowel problems, and sexual dysfunction, and related quality-of-life instruments.

resultsAt a median of 9.4 years after treatment (range, 7.4-12.1 years), participants' demographic and clinical characteristics were similar. Patient-reported outcomes were reported as mean (SD) scale score for standard dose vs high dose: urinary obstruction/irritation (23.3 [13.7] vs 24.6 [14.0]; P = .36), urinary incontinence (10.6 [17.7] vs 9.7 [15.8]; P = .99), bowel problems (7.7 [7.8] vs 7.9 [9.1]; P = .70), sexual dysfunction (68.2 [34.6] vs 65.9 [34.7]; P = .65), and most other outcomes were also similar, although patients receiving standard dose whose cancers had more often progressed expressed less confidence that their cancers were under control (mean [SD] scale score for standard dose, 76.0 [25.4] vs high dose, 86.2 [17.9]; P < .001). Many patients characterized their urinary and bowel function as normal despite reporting symptoms that, for other prostate cancer patients before and early after cancer treatment, caused substantial distress.

conclusionAmong men with clinically localized prostate cancer, treatment with higher-dose radiation compared with standard dose was not associated with an increase in patient-reported prostate cancer symptoms after a median of 9.4 years.