Although epidemiologic studies suggest that metabolic syndrome (MetS) increases the risk of colorectal cancer, its effect on cancer mortality remains controversial.
The authors used the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database (1998-2006) to conduct a retrospective cohort study of 36,079 patients with colon cancer to determine the independent effect of MetS and its components on overall survival (OS) and recurrence-free rates (RFRs). Data on MetS and its components were ascertained from Medicare claims. OS and RFRs in patients with and without MetS and its components were compared using multivariate Cox models.
MetS had no apparent effect on OS or RFR. Both elevated glucose/diabetes mellitus (DM) and elevated hypertension were associated with worse OS (adjusted hazard ratio [aHR], 1.17 [95% confidence interval, 1.13-1.21] and 1.08 [95% confidence interval, 1.03-1.12], respectively) and worse RFRs (aHR, 1.25 [95% confidence interval, 1.16-1.34] and 1.22 [95% confidence interval, 1.12-1.33], respectively). In contrast, dyslipidemia was associated with improved survival (aHR, 0.77; 95% confidence interval, 0.75-0.80) and reduced recurrence (aHR, 0.71; 95% confidence interval, 0.66-0.75). These effects were consistent for both men and women and were more pronounced in patients with early stage disease.
MetS had no apparent effect on colon cancer outcomes, probably because of the combined adverse effects of elevated glucose/DM and hypertension and the protective effect of dyslipidemia in patients with nonmetastatic disease. The authors concluded that patients who have early stage colon cancer with elevated glucose/DM and/or hypertension may benefit from more intensive surveillance and/or broader use of adjuvant therapy and that trials to define the benefits of low-fat diets, insulin-lowering agents, and statins on recurrence/survival in patients with nonmetastatic colon cancer are warranted.