Long-term QOL outcome after proton beam monotherapy for localized prostate cancer.

Abstract

68 Background: High-dose conformal proton radiation for localized prostate cancer results in favorable clinical outcomes and low toxicity rates. Here, we report long-term quality of life (QOL) outcome for men treated with conformal protons. Methods: Serial QOL questionnaires were administered to men who received proton radiation. Long-term questionnaires (minimum 2 years) were completed by 72 patients. Men were stratified into functional groups from their baseline questionnaires (normal, intermediate or poor function) for each symptom domain. Symptom scores were calculated at baseline and long-term follow-up and expressed as mean values. QOL changes were assessed overall and within functional groups in a paired fashion using the Student's t-test. Results: The median age at treatment and follow-up were 66 years and 44 months, respectively. The median dose was 82 GyE (range 74-82 GyE). For all 72 patients, there were increased scores for incontinence (ID) (3.2 baseline vs. 9.9 long-term, p=<0.001), obstructive/irritative voiding (OID; 20 vs. 24, p=0.028), bowel (BD; 4.4 vs. 8.0, p=0.001) and sexual dysfunction (SD; 25 vs. 48, p<0.001). When stratified by functional category, more specific estimates were possible. For ID, only normal function was associated with a significant increased score (0 vs. 8.4 at baseline and long-term, p=<0.001); for OID, only the group with normal baseline function showed a significant increased score (12 vs. 17, p=0.01); similarly for BD, only men with normal function had a significant increased score (0 vs. 5.4, p<0.001). For SD, the score increased in men with normal (1.4 vs. 30, p<0.001) and intermediate function (17 vs. 46, p<0.001). Conclusions: Patient reported outcomes are sensitive indicators of treatment related sequelae and here quantitate, for the first time, the long-term consequences of proton monotherapy for prostate cancer. Analysis by baseline functional category is a useful means of predicting long-term QOL scores for an individual patient. High-dose proton radiation was associated with small increases in bowel dysfunction, obstructive/irritative voiding dysfunction and incontinence. With long term follow-up, sexual dysfunction increased more than any other symptom domain. No significant financial relationships to disclose.