Is Older Age an Independent Prognostic Factor of Survival in Metastatic Colorectal Cancer?

Introduction: Older patients (<= 75 years) with advanced colorectal cancer (CRC) may have worse survival than non-older patients. We hypothesized that, rather than age alone, concurrent factors may be more relevant for real-world survival. Methods: Patients diagnosed with CRC in a 5-year period (2014-2018) were analyzed to determine which factors influenced in overall survival (OS). Kaplan-Meier method was used to estimate OS. Univariate and multivariate analysis was conducted by Cox regression analysis. The study was approved by Ethics Committee. Results: Out of 477 patients diagnosed with CRC, 231 had advanced disease. Ninety-two patients (40%) were older than 75 years; median OS (mOS) was 17.1 m (95% CI: 14.3-23.3), p < 0.001. In non-older patients, mOS was 26.7 m (95% CI: 21.9-32.6), p < 0.001. We evaluated eighteen concurrent factors that included characteristics related to the patient (age, sex, comorbidities, polypharmacy, Eastern Cooperative Oncology Group (ECOG), and nutritional status), to the tumor (stage at diagnosis, tumor side, molecular profile, tumor burden, location, and number of metastasis), and to the treatment administered (systemic treatment for advanced disease, chemotherapy schedule and number of lines, severe adverse events and dose reductions, and surgery of liver metastasis). In the univariate analysis, age at diagnosis, ECOG, nutritional status, tumor side, molecular profile, tumor burden, systemic treatment for advanced disease, and surgery of liver metastases had significant impact on survival. However, multivariate analysis revealed that only four factors (tumor burden, nutritional status, systemic treatment for advanced disease, and surgery of liver metastases) were independently associated with OS but not older age at diagnosis. Conclusion: Older age is not an independent survival prognostic factor for advanced CRC. Tumor burden, nutritional status, systemic treatment for advanced disease, and surgery of liver metastasis were significant factors associated with OS. These findings suggest that older patients should not be excluded from cancer treatment based on age alone.