Analysis linking UCLA PCI with Expanded Prostate Cancer Index Composite: an evaluation of health related quality of life in Japanese men with localized prostate cancer.

Purpose: We evaluated the correspondence between UCLA PCI and the Extended Prostate Cancer Index Composite for Japanese patients with localized prostate cancer.
Materials and Methods: A total of 385 patients treated with retropubic radical prostatectomy, external beam radiation, hormonal therapy or select watchful waiting from 2002 to 2006 were enrolled. For this study we used equipercentile linking, a technique that identifies scores on the 2 measures that have the same percentile rank.
Results: Urinary and sexual functions showed a strong correlation (r = 0.85 and 0.93, respectively, p <0.0001). In contrast, the correlation for bowel function was relatively weak (r = 0.47, p <0.0001). The correlations of each Extended Prostate Cancer Index Composite bother domain with UCLA PCI were 0.6 (p <0.0001). The linking between each scale of the Extended Prostate Cancer Index Composite and UCLA PCI domains showed that an Extended Prostate Cancer Index Composite urinary function score of 73 was equivalent to a UCLA PCI score of 60. With regard to urinary bother an Extended Prostate Cancer Index Composite score of 69 to 84 was equivalent to a UCLA PCI score of 75. A sexual function score of 18 on UCLA PCI corresponded to an Extended Prostate Cancer Index Composite score of 12 and a sexual bother score of 50 on UCLA PCI corresponded to an Extended Prostate Cancer Index Composite score of 56 to 88.
Conclusions: The urinary and sexual domains of UCLA PCI and the Extended Prostate Cancer Index Composite showed strong correlations. In contrast, the correlation for the bowel domain was relatively weak. The results of the linking analysis between UCLA PCI and the Extended Prostate Cancer Index Composite may have implications useful for their interpretation.