Dietary glycemic load and cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803.

BACKGROUND The influence of glycemic load and related measures on survival among colon cancer patients remains largely unknown. METHODS We conducted a prospective, observational study of 1011 stage III colon cancer patients reporting dietary intake during and 6 months after participation in an adjuvant chemotherapy trial. We examined the influence of glycemic load, glycemic index, fructose, and carbohydrate intakes on cancer recurrence and mortality using Cox proportional hazards regression; all tests of statistical significance were two-sided. RESULTS Stage III colon cancer patients in the highest quintile of dietary glycemic load experienced an adjusted hazard ratio (HR) for disease-free survival of 1.79 (95% confidence interval [CI] = 1.29 to 2.48), compared with those in the lowest quintile (P (trend) across quintiles <.001). Increased glycemic load was associated with similar detriments in recurrence-free (P (trend) across quintiles <.001) and overall survival (P (trend) across quintiles <.001). These associations differed statistically significant by body mass index (BMI) (P (interaction) =.01). Whereas glycemic load was not associated with disease-free survival in patients with BMI < 25kg/m(2), higher glycemic load was statistically significant associated with worse disease-free survival among overweight or obese participants (BMI ≥ 25kg/m(2); HR = 2.26; 95% CI = 1.53 to 3.32; P (trend) across quintiles <.001). Increasing total carbohydrate intake was similarly associated with inferior disease-free, recurrence-free, and overall survival (P (trend) across quintiles <.001). CONCLUSION Higher dietary glycemic load and total carbohydrate intake were statistically significant associated with an increased risk of recurrence and mortality in stage III colon cancer patients. These findings support the role of energy balance factors in colon cancer progression and may offer potential opportunities to improve patient survival.