Background: Even though obesity is a well-established risk factor for developing colon cancer, its prognostic value is not very well understood. The present study elucidated the effect of obesity, as measured by the body mass index (BMI) and body surface area (BSA), on colon cancer outcomes.
Patients and methods: Patients with a diagnosis of stage III colon cancer from 2011 to 2016 who had undergone adjuvant chemotherapy in Alberta, Canada were identified. The demographic variables, treatment characteristics, and survival data were collected from the electronic medical records. Obesity was defined using the BMI in accordance with the World Health Organization criteria, and BSA was categorized as ≤ 2.0 m2 (low) and > 2.0 m2 (high). The effect of BMI and BSA on 5-year cancer-specific survival (CSS) and overall survival (OS) was analyzed using univariate and multivariate analysis.
Results: A total of 915 patients were identified with a median age of 64 years. Of these, 37% were overweight or obese, and the BSA was high in 42% of the patients. The survival outcomes for the obese and underweight patients were not significantly different from those with a normal BMI (P = .61 and P = .30 for OS and CSS, respectively). Similarly, no correlation was found between BSA and OS or CSS. Although 21% of patients experienced a > 10-week delay in receiving adjuvant chemotherapy, neither BMI nor BSA correlated significantly with chemotherapy timing (P = .45).
Conclusions: Our results suggest that BMI and BSA do not correlate with survival outcomes in patients with stage III colon cancer. The role of a healthy lifestyle in an improved colon cancer prognosis might not be driven by its effects on obesity.
Keywords: Body mass index; Body surface area; Chemotherapy timing; Medical oncology; Survival.
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