Causes of mortality in older patients with stage 3 colon cancer

Life expectancy plays a key role in the selection of patients with stage III colon cancer for adjuvant chemotherapy, but little is known about causes of mortality in older patients with colon cancer. We aimed to examine causes of death in this population and compare these causes between patients who received chemotherapy and those who did not. Specifically, we chose to examine the rates of death related to recurrent colon cancer versus non colon cancer.

Patients aged 50 and older diagnosed with stage III colon cancer between 2005 and 2009 were included. Patients were divided into "younger" (aged 50-69) and "older" (aged 70+). Causes of death, which were categorized into colon cancer versus non-colon cancer related.

1361 patients were included, 50% of whom were 70 or older. Younger patients were more likely to receive adjuvant chemotherapy (90% vs. 60%). 601 patients died in the follow up period. Deceased patients in the younger group were more likely to die from colon cancer (81% vs. 62%). The most common cause of non-colon cancer death was other primary malignancies in younger patients and cardiovascular diseases in older patients. In older patients who received chemotherapy, 41% died; 89% of these deaths were related to colon cancer. In older patients who did not receive chemotherapy 72% died, with 38% of patients ultimately dying from colon cancer.

Older patients remain under-treated with chemotherapy. Although non-colon cancer deaths were more frequent in older patients with cancer, colon cancer was a still a significant cause of mortality. These deaths may be preventable with adjuvant chemotherapy.