Charlson Comorbidity score influence on prostate cancer survival and radiation-related toxicity

In addition to survival endpoints, we explored the impact of Charlson Comorbidity-Index (CCI) on the acute and late toxicities in men with localized prostate cancer who received dose-escalated definitive radiotherapy (RT).

CCI scores at diagnosis and survival outcomes were identified for men with intermediate/high-risk prostate cancer treated with RT (1/2007-12/2012). Study-cohort was accordingly grouped into no, mild and severe comorbidity (CCI-0, 1 or 2+). CCI-groups were compared for demographics, prognostic-factors; and RT-related toxicities based on RTOG/CTCAE criteria. Kaplan-Meier curves and Uni/multivariate (MVA) analyses were used to examine the influence of CCI-group on overall (OS), disease-specific (DSS) and biochemical-relapse free (BRFS) survival.

We included 257 patients with median age 73 years (48-85), 53% African-American and 67% had intermediate-risk. Median prostate RT-dose was 76 Gy; and 47% received androgen-deprivation therapy. CCI-0,1,2+ groups encompassed 76 (30%), 54 (21%) and 127 (49%) patients, respectively and were well-balanced. Ten and 15-years OS were significantly different (76% versus 46% versus 55% for 10-years OS and 53% versus 31% versus 14% for 15-years OS for CCI-0 versus CCI-1[HR:2.25; CI[1.31-3.87]] versus CCI-2+[HR:2.73; CI[1.73-4.31]]; p < 0.001. CCI-0 had better DSS than CCI-2+ (HR:2.23; CI[1.06-4.68]; p = 0.03) and BRFS was similar (p = 0.99). Late G2/3 RT-toxicities were more common in CCI-2+ (47%) than CCI-1 (44%) and CCI-0 (29%), p = 0.032; with non-different acute-toxicities (p = 0.62). On MVA, increased CCI was deterministic for OS (HR:3.65; CI [1.71:7.79]; p < 0.001) and was only marginal for DSS (HR:2.55; CI [0.98-6.6]; p = 0.05) with no impact on BRFS (p > 0.05).

Higher CCI is a significant predictor for late RT-related side-effects and shorter OS in men with localized prostate cancer. Baseline comorbidities should be considered during initial counseling and follow up visits.