Gut doi:10.1136/gutjnl-2013-304701
  • Recent advances in clinical practice

Obesity and colorectal cancer

  1. Myriam Martel4
  1. 1INSERM-Centre d'Investigations Cliniques Plurithématique 803 (CIC-P 803), CHU du Bocage, Dijon, France
  2. 2Service d'hépato-gastroentérologie, CHU du Bocage, Dijon, France
  3. 3Faculté de Médecine, Centre de Recherche Lipide Nutrition et Cancer, U866, Dijon, France
  4. 4Divisions of Gastroenterology, McGill University Health Centre, McGill University, Montréal, Québec, Canada
  5. 5Department of Epidemiology Biostatistics and Occupational Health, McGill University Health Centre, McGill University, Montréal, Québec, Canada
  1. Correspondence to Professor Marc Bardou, INSERM CIC-P 803, CHU du Bocage, 14, rue Gaffarel, BP 77908, Dijon Cedex 21079, France; marc.bardou{at}
  • Received 30 May 2012
  • Revised 6 February 2013
  • Accepted 8 February 2013
  • Published Online First 12 March 2013


Excess body weight, as defined by the body mass index (BMI), has been associated with several diseases and includes subjects who are overweight (BMI≥25–29.9 kg/m2) or obese (BMI≥30 kg/m2). Overweight and obesity constitute the fifth leading risk for overall mortality, accounting for at least 2.8 million adult deaths each year. In addition around 11% of colorectal cancer (CRC) cases have been attributed to overweight and obesity in Europe. Epidemiological data suggest that obesity is associated with a 30–70% increased risk of colon cancer in men, whereas the association is less consistent in women. Similar trends exist for colorectal adenoma, although the risk appears lower. Visceral fat, or abdominal obesity, seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m2 increase in BMI confers additional risk (HR 1.03). Obesity might be associated with worse cancer outcomes, such as recurrence of the primary cancer or mortality. Several factors, including reduced sensitivity to antiangiogenic-therapeutic regimens, might explain these differences. Except for wound infection, obesity has no significant impact on surgical procedures. The underlying mechanisms linking obesity to CRC are still a matter of debate, but metabolic syndrome, insulin resistance and modifications in levels of adipocytokines seem to be of great importance. Other biological factors such as the gut microbita or bile acids are emerging. Many questions still remain unanswered: should preventive strategies specifically target obese patients? Is the risk of cancer great enough to propose prophylactic bariatric surgery in certain patients with obesity?

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