Impact of comorbidity on survival by tumour location: Breast, colorectal and lung cancer (2000-2014)

Abstract

Background: To assess the impact of comorbidity, measured by the Charlson Comorbidity Index (CCI), on survival in breast, colorectal and lung cancer.

Methods: We identified 3455 breast cancer, 3336 colorectal cancer and 2654 lung cancer patients through the Hospital del Mar cancer registry. The prevalence of comorbidities according to the CCI was calculated. Kaplan-Meier curves and the log-rank test were used to compare survival curves for each cancer location. Cox regression was used to calculate survival hazard ratios and 1-, 3- and 5-year mortality rate ratios adjusted by age, sex, CCI, place of first consultation, stage, treatment and period of diagnosis.

Results: The overall unadjusted 5-year follow-up survival proportion was 82.6% for breast cancer, 55.7% for colorectal cancer, and 16.3% for lung cancer. Overall survival was associated with CCI≥3 in breast cancer (HR: 2.33 95%CI: 1.76-3.08), colorectal cancer (HR: 1.39; 95%CI: 1.13-1.70) and lung cancer (HR: 1.22; 95%CI: 1.06-1.40). In breast cancer, the higher the CCI, the higher the adjusted mortality rate ratio and differences were greater in 5-year than in 1-year follow-up survival.

Conclusions: Comorbidity is a significant predictor of overall survival in cancer patients; however, it has a stronger impact on survival in breast cancer than in colorectal and lung cancer.

Keywords: Breast cancer; Colorectal cancer; Comorbidity; Lung cancer; Survival.