Prognostic value of comorbidities in older patients with cancer: the ELCAPA cohort study

BACKGROUND: In older patients, comorbidities competed with cancer for mortality risk. We assessed the prognostic value of comorbidities in older patients with cancer. PATIENTS AND METHODS: We analysed all patients >70 years of age with colorectal, breast, prostate, or lung cancer included in the prospective ELCAPA cohort. The Cumulative Illness Rating Scale-Geriatrics (CIRS-G) score was used to assess comorbidities. The primary endpoint was overall survival (OS) at 3, 12, and 36 months. The adjusted difference in the restricted mean survival time (RMST) was used to assess the strength of the relationship between comorbidities and survival. RESULTS: Of the 1551 patients included (median age 82 years; interquartile range 78-86 years), 502 (32%), 575 (38%), 283 (18%), and 191 (12%) had colorectal, breast, prostate, and lung cancer, respectively, and 50% had metastatic disease. Hypertension, kidney failure, and cognitive impairment were the most common comorbidities (67%, 38%, and 29% of the patients, respectively). A CIRS-G score >17, two or more severe comorbidities, more than seven comorbidities, heart failure, and cognitive impairment were independently associated with shorter OS. The greatest effect size was observed for CIRS-G >17 (versus CIRS-G <11): at 36 months, the adjusted differences in the RMST (95% confidence interval) were −6.0 months (−9.3 to −2.6 months) for colorectal cancer, −9.1 months (−13.2 to −4.9 months) for breast cancer, −8.3 months (−12.8 to −3.9 months) for prostate cancer, and −5.5 months (−9.9 to −1.1 months) for lung cancer (P < 0.05 for all). CONCLUSIONS: Comorbidities’ type, number, and severity were independently associated with shorter OS. A 17-point cut-off over 56 for the total CIRS-G score could be considered in clinical practice.