Influence of body mass index on outcomes and treatment‐related toxicity in patients with colon carcinoma

BACKGROUND Obesity is a risk factor for the development of colon carcinoma. The influence of body mass index (BMI) on long‐term outcomes and treatment‐related toxicity in patients with colon carcinoma has not been well characterized. METHODS This cohort study was conducted within a large, randomized adjuvant chemotherapy trial of 3759 men and women with high‐risk, Stage II and Stage III colon carcinoma who were treated between 1988 and 1992 throughout the United States. With a median follow‐up of 9.4 years, the authors examined the influence of BMI on disease recurrence, overall survival, and treatment‐related toxicity. RESULTS Compared with women of normal weight (BMI, 21.0–24.9 kg/m2), obese women with colon carcinoma (BMI ≥ 30.0 kg/m2) experienced significantly worse overall mortality (hazard ratio [HR], 1.34; 95% confidence interval [95% CI], 1.07–1.67) and a nonsignificant increase in the risk of disease recurrence (HR, 1.24; 95% CI, 0.98–1.59). The influence of BMI among women was not related to any differences in chemotherapy dose‐intensity across categories of BMI. In contrast, BMI was not related significantly to long‐term outcomes among male patients in this cohort. Among all study participants, obese patients had significantly lower rates of Grade 3–4 leukopenia and lower rates of any Grade ≥ 3 toxicity compared with patients of normal weight. CONCLUSIONS Among women with Stage II–III colon carcinoma, obesity was associated with a significant increase in overall mortality as well as a borderline significant increase in disease recurrence. Nonetheless, obesity was not associated with any increase in chemotherapy‐related toxicity. Cancer 2003;98:484–95. © 2003 American Cancer Society. DOI 10.1002/cncr.11544 Higher body mass index (BMI) is associated with an increased risk of developing colon carcinoma, although its influence on patients with the disease is unknown. Among women with Stage II–III colon carcinoma, obesity was associated with significantly worse overall mortality as well as a borderline significant increase in disease recurrence; this correlation was not seen in men across BMI classes.