Impact of age and comorbidity on survival in colorectal cancer

Patients with colorectal cancer are often excluded from clinical trials based on age or a poor performance score. However, 70% of colorectal cancer is diagnosed in patients over 65. Evaluation on the influence of age and comorbidity on survival and cause of death in a non-selected population.

Included were 621 consecutive patients with colorectal cancer. An extensive chart review was performed for 392 patients with colon cancer and 143 patients with rectal cancer. Analyses were performed separately for both groups.

Median survival of colon cancer patients was 5.13 years, 131 patients (34.3%) died from tumour progression. Age and comorbidity were significant predictors for overall survival (P<0.001). Age was also a significant predictor of cause of death (P=0.001). In rectal cancer patients median survival was 4.67 years, 51 (35.7%) of patients died from tumour progression. Neither age nor comorbidity was significant predictors of survival. Age was a significant predictor of cause of death (P<0.001).

In colon cancer patient age and comorbidity predict survival. This represents possible bias or a reduced survival benefit of treatment, and is an indication that colon cancer is not the prognosis defining illness in the majority of patients. In rectal cancer patients neither age or comorbidity significantly impacted survival.