Development and validation of the korean version of expanded prostate cancer index composite: questionnaire assessing health-related quality of life after prostate cancer treatment.
OBJECTIVE
Although the quality of life (QoL) of prostate cancer (PCa) patients is a major issue, there is no unified and useful methodology for assessing QoL. The Expanded Prostate Cancer Index Composite (EPIC) is a globally used tool to measure QoL after PCa treatment that comprises urinary, bowel, sexual, and hormonal domains. Acknowledging the need for such a tool applicable to Korean PCa patients, we translated EPIC into Korean and validated the new version.


METHODS
The Korean version of EPIC was devised by translation, back-translation, and reconciliation. Subsequently, we randomly selected 153 patients with localized PCa treated with radical perineal prostatectomy (67, 43.8%), radical retropubic prostatectomy (19, 12.4%), laparoscopic radical prostatectomy (12, 7.8%), robot-assisted laparoscopic radical prostatectomy (36, 23.5%), and high-intensity focused ultrasound ablation of the prostate (19, 12.4%) and asked them to complete EPIC. Reliability was assessed by test-retest correlation and Cronbach's alpha. Validity was assessed by factor analysis, interscale correlation, and correlation with Functional Assessment of Cancer Therapy-Prostate (FACT-P).


RESULTS
Test-retest correlation and Cronbach's alpha were high in each of the domains (0.92, 0.91, 0.76, 0.84 and 0.86, 0.84, 0.92, 0.83, p<0.0001). Interscale correlation among the domains was low (r<0.37), which indicated that EPIC is composed of proper domains. Interscale correlation between the function and bother subscales was high (0.94, 0.81, 0.84 and 0.80, p<0.0001). EPIC domains had low correlation with FACT-P, permitting complementary use.


CONCLUSIONS
The Korean version of EPIC was developed by a proper process, as evident by its high reliability and validity. Therefore, it is a reliable, comprehensive, systematic method that evaluates QoL in Korean patients after PCa treatment. Furthermore, it can be adapted as an objective methodology for research globally.
Chung
Kyung Jin
KJ
Department of Urology, Gachon University Gil Hospital, Incheon, Korea.
Kim
Jung Jun
JJ
Lim
Soo Hyun
SH
Kim
Tae Heon
TH
Han
Deok Hyun
DH
Lee
Sung Won
SW