Health Related Quality of Life in Japanese Men With Localized Prostate Cancer Treated With Current Multiple Modalities Assessed by a Newly Developed Japanese Version of the Expanded Prostate Cancer Index Composite

Abstract

Health related quality of life in Japanese men with localized prostate cancer treated with current multidisciplinary treatment modalities was assessed using a newly developed Japanese version of the Extended Prostate Cancer Index Composite. We evaluated psychometric properties of the Japanese version of the Extended Prostate Cancer Index Composite. A cross-sectional analysis of health related quality of life was done in 460 patients treated with radical prostatectomy, external beam radiation therapy, permanent (125)I seed implantation androgen deprivation therapy or watchful waiting. Patients were enrolled in January to July 2005. Serum testosterone was measured in all participants. Missing values ranged from 0.4% to 16.3% with 10% or greater observed for 15 of 50 items (30%). A missing value of 10% or greater correlated with higher age and lower educational background (p<0.05). Internal consistency reliability was 0.7 or higher for almost all subscales except the bowel function and hormonal function subscales. Test-retest reliability and factor validity were successfully verified. Known groups validity revealed significant improvement in urinary domain scores with time in patients treated with radical prostatectomy plus permanent (125)I seed implantation. Bowel domain scores were worse in patients treated with external beam radiation therapy compared to the other modalities. Decreased hormonal domain scores correlated with low serum testosterone (p<0.001). Salvage androgen deprivation therapy after radical prostatectomy negatively influenced sexual function but not sexual bother. Reliability and validity of the Japanese version of the Extended Prostate Cancer Index Composite were verified, although revision is needed for it to be more comprehensible for elderly patients and those with low education. It can be used for cross-cultural assessment of health related quality of life in patients with localized prostate cancer treated with current multidisciplinary treatment modalities.