Clinical Effectiveness of Oncological Treatment in Metastatic Colorectal Cancer Is Independent of Comorbidities and Age

SIMPLE SUMMARY: Colorectal cancer (CRC) is the third most common cancer worldwide. As with many other cancers, the risk for CRC increases with age. This is also true for comorbidities, which may hamper sufficient treatment of the cancer. Due to restrictive inclusion criteria, older patients and patients with comorbidities are underrepresented in clinical trials. Comprehensive knowledge about modern effectiveness of oncological treatments in older and/or comorbid patients is sparse. Due to the lack of clinical trials, this issue is investigated in real-life settings predominantly. In our retrospective study we show that patients benefit from oncological treatments irrespective of comorbidities, measured by the age-adjusted Charlson Comorbity (aaCCI) index, and age. Differences found in treatment outcomes are marginal and are likely due to less intense treatment of comorbid or elderly patients. Balancing risk and benefit for treatment decisions should take potential under-treatment of comorbid and older patients into account. ABSTRACT: We aimed to investigate the effectiveness of oncological treatments in metastatic CRC related to comorbidities and age. This retrospective study included 1105 patients from three oncological centers. aaCCI and CCI was available from 577 patients. An aaCCI > 3 was of the highest predictive value compared to other aaCCI-levels, CCI or age (p < 0.001 for all). Treatment (best supportive care (BSC), systemic treatment only (STO) and resection of metastases (ROM)) significantly prolonged survival in patients with aaCCI > 3 (STO: HR 0.39, CI 0.29–0.51; ROM: HR 0.16, CI 0.10–0.24) and patients older than 70 years (STO: HR 0.56, CI 0.47–0.66; ROM: HR 0.23, 0.18–0.30). Median overall survival was shorter in patients with aaCCI or age > 70 years and interaction for treatment type not significant for aaCCI, but significant for age older or younger than 70 years (STO: p = 0.01; ROM p = 0.02). BSC is more often considered as optimal care for patients with an aaCCI > 3 (37.6% vs. 12.4%; p < 0.001) or age > 70 years (35.7% vs. 11.2%; p < 0.001). Older patients or patients with comorbidities benefit from cancer-specific therapy independently of their age and comorbidities.