[The impact of obesity on the histopathological characteristics of colorectal tumours. An observational study].

Background: To asses the influence of body mass index on the tumour characteristics of patients subjected to colorectal cancer surgery.

Materials And Methods: Retrospective observational study. Patients subjected to curative elective colorectal cancer surgery at Hospital Josep Trueta de Girona (Spain), from 1990 to 2001. Univariate and bivariate analyses were performed to evaluate differences in tumour characteristics with regard to body mass index.

Results: A total of 369 patients with colorectal cancer were included into the study, 213 (57.7%) with colon cancer, and 156 (42.3%) with rectal cancer. For colon cancer patients, when the BMI was higher than 25 kg/m(2), the tumour grade was worst (P=0.011), and when BMI was above 30 kg/m(2) there were more lymph node metastasis. For rectal tumours, the higher the BMI, the more lymph node metastasis (P=0.041), and higher tumour stage (P=0.023).

Conclusions: Patients with a higher BMI have more lymph node metastasis when submitted to elective colorectal cancer surgery. In the case of colon cancer they also have worst tumour grades, and in the case of rectal cancer, a more advanced tumour stage.