Impact of Charlson Comorbidity Index Varies by Age in Patients with Prostate Cancer Treated by Radical Prostatectomy: A Competing Risk Regression Analysis

Abstract

To investigate the prognostic impact of the Charlson comorbidity index (CCI) on either cancer-specific mortality (CSM) or other-cause mortality (OCM) according to age in patients with prostate cancer (PC) who underwent radical prostatectomy (RP). Data from 336 patients who underwent RP for PC between 1992 and 2005 were analyzed. Variables, including the preoperative prostate-specific antigen (PSA), prostate volume, clinical stage, and pathologic stage, were compared across age groups (<65 or ≥65years old). Preexisting comorbidities were evaluated by the CCI, and patients were classified into two CCI score categories (0 or ≥1). The median (interquartile range) follow-up period was 96 (85-121) months. Subjects were divided into two subgroups according to age: <65years (n=151) or ≥65years (n=185). There was no significant difference in PSA, biopsy Gleason sum, body mass index, pathologic stage, or CCI between the two age groups. OCM was significantly associated with the CCI score (P=0.011). Cumulative incidence estimates obtained from competing risk regression analysis indicated that CCI was not associated with CSM (P=0.795) or OCM (P=0.123) in the ≥65-year group. However, in men <65years, cumulative incidence estimates for OCM were significantly associated with CCI (P=0.036). CCI was independently associated with OCM after RP, but only in men <65years old. CCI was not associated with CSM in either age group. Accordingly, a thorough evaluation of patient's comorbidities is mandatory when considering aggressive surgical treatment, especially in relatively young patients.