Changing prognosis of metastatic colorectal adenocarcinoma: Differential improvement by age and tumor location

BACKGROUND Over the past 2 decades, significant progress has been made in the field of metastatic colorectal cancer (mCRC) regarding new imaging techniques, surgical interventions, and systemic therapy. It is not known whether the benefit from these interventions has extended overall survival (OS) within the general mCRC population. A population-based survival analysis of newly diagnosed patients who presented with mCRC was therefore performed. METHODS Survival statistics were extracted from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with mCRC between 1988 and 2008. Demographic variables collected included age, race, and tumor grade. Survival was analyzed using the Kaplan-Meier method and extended Cox proportional hazard model as appropriate. RESULTS The study population consisted of 42,347 patients diagnosed with mCRC between 1988 and 2008 (52% women; mean age, 67 years). The 1- and 2-year estimated OS rates were 44% and 22%, respectively. Prognostic variables included race, sex, age, tumor location, and year of diagnosis. Median OS improved from 8 months to 14 months between 1988 and 2008. Significant improvements in OS were seen for all disease sites, but especially for descending colon cancers. Whereas the median OS increased by 13 months in patients ≤50 years of age and by 7 months in patients 51-70 years of age, the median OS of patients >70 years of age increased by only 1 month between 1988 and 2008. CONCLUSIONS There has been a continuous improvement in OS of patients diagnosed with mCRC between 1988 and 2008, especially for left-sided tumors. Little improvement has been seen in patients over 70 years of age.