Overweight but not obesity is associated with decreased survival in rectal cancer

Aim of the study
To analyse the influence of overweight and obesity in disease-specific survival (DSS) in rectal cancers at stages I–III in a population with high prevalence of overweight/obesity.

Material and methods
The population (N = 304) consisted of Mexican patients with stage I–III rectal cancer during the period between 2009 and 2015. Patients were divided based on their body mass index (BMI) into normal weight 18–25 kg/m², overweight 25–29 kg/m², and obesity BMI > 30 kg/m² groups. Comparison of clinicopathologic features and survival analysis were performed.

Results
The median age was 58 years (interquartile range [IQR] 50–65) and the mean BMI was 26.03 ±4.06 kg/m². Patients in the obesity and overweight groups received a lower proportion of preoperative treatment and had a higher proportion of patients in stage II. Overweight patients had a lower baseline neutrophil/lymphocyte ratio and lower survival rate than patients with normal weight and with obesity (mean survival of 69.5 months vs. 81.15 months and 86.4 months, respectively). The estimated five-year DSS was 51% for the overweight group, 81% for the normal group, and 82% for the obesity group (p = 0.026).

Conclusions
Patients with stage I–III rectal cancer in the overweight group showed a lower DSS compared to groups with normal weight and with obesity, with the last two being similar.