Obesity and colorectal cancer

Abstract

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/m(2)) or obese (BMI ≥ 30 kg/m(2)). 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/m(2) 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 microbiota 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?

Lung cancer patients with synchronous colon cancer

“…It is generally accepted that cigarette smoking plays an important role in lung carcinogenesis (4). In addition, epidemiological data suggested that obesity is associated with an increased risk of colon cancer (10). Diabetes and high dietary meat intake are also associated with an increased risk of colon cancer (11).…”

Colorectal Cancer Incidence and Mortality in China, 2010

“…We can see from the survey that the incidence of colorectal cancer in urban areas is obviously higher than in rural areas (26.70/100,000 in urban and 15.01/100,000 in rural), which can be attributed to the dietary habits, different life-style and air pollution (Dai et al, 2007;Guh et al, 2009;Harriss et al, 2009;Bardou et al, 2013;Johnson et al, 2013). The people in urban areas are more likely to eat meat, high-sugar drinks, no-fiber foods and irregular eating habits (Guh et al, 2009;Harriss et al, 2009).…”

Results of screening in Lublin Province, Poland, for colorectal cancer and neoplastic polyps - the role of environmental factors

“…However, researchers suppose that metabolic syndromes, insulin resistance, modified adipocitokine levels and molecular mediators are involved, although these mechanisms too have not been established to-date. One of the hypotheses suggests high insulin levels and insulin-related growth factors favour CRC development [20]. Recently published research has focused on the involvement of inflammatory processes, adipokines and estrogens in CRC.…”