Background: In randomised controlled trials, the median overall survival (OS) for patients with metastatic colon cancer has improved. However, the results of randomised controlled trials should be interpreted with caution and cannot simply be extrapolated to the general practice. We retrospectively analysed population-based survival data of patients who presented with metastatic colon cancer at diagnosis.
Patients and methods: All patients diagnosed with primary metastatic colon cancer from 1990 to 2004 in the registration area of the Eindhoven Cancer Registry were included. Date of diagnosis was divided into four periods (1990-1994, 1995-1999, 2000-2002, and 2003-2004) according to the availability of chemotherapy for metastatic colon cancer. We assessed OS according to chemotherapy use and period.
Results: Of the 1769 patients, 30.6% received chemotherapy. Chemotherapy use over time increased from 24% in 1990-1994 to 55% in 2000-2004 for patients aged <70 years and from 2% to 22% in patients aged 70 years and older. Median survival for patients diagnosed in 1990-1994 was 26 [95% confidence interval (CI) 22-32] weeks, while patients diagnosed in 2003-2004 had a median survival of 39 (95% CI 31-48) weeks. Patients who did not receive chemotherapy had a survival of 22 (95% CI 20-25) weeks, while the survival for patients who did receive chemotherapy was 57 (95% CI 51-65) weeks. OS decreased with increasing age (P < 0.0001). In the multivariate survival analysis, chemotherapy use, increasing age, having multiple comorbid conditions, and having more than one tumour site significantly affect survival, with the strongest effect of chemotherapy use.
Conclusion: Palliative chemotherapy significantly improved OS in unselected patients with metastatic colon cancer.