Excess Weight Associated With 8 Additional Cancers

Excess body weight and obesity are associated with 8 additional cancers, including stomach, liver, gall bladder, pancreas, ovary, meningioma, thyroid, and multiple myeloma, according to a new review of more than 1000 epidemiologic studies.

In addition, a review suggests a causal cancer-preventive effect of intentional weight loss.
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The researchers reaffirmed the absence of excess body fatness lowers the risk of cancer at the organ sites previously identified: the colon, esophagus (adenocarcinoma), kidney (renal-cell), breast (postmenopausal), and corpus uteri. Furthermore, they identified an additional 8 cancers for which sufficient evidence now shows the absence of body fatness lowers cancer risk.

For cancers of the colon, rectum, gastric cardia, liver, gallbladder, pancreas, and kidney and for esophageal adenocarcinoma, significant associations between body mass index (BMI) and cancer risk were reported, with positive dose-response relationships. Relative risks from meta-analyses or pooled analyses were 1.2-1.5 for overweight (BMI 25.0-29.9) and 1.5-1.8 for obesity (BMI ≥ 30.0) with respect to cancers of the colon, gastric cardia, liver, gallbladder, pancreas, and kidney; the relative risk for esophageal adenocarcinoma was up to 4.8 for a BMI of ≥ 40.

They found limited evidence for an association between excess body fatness and fatal prostate cancer, diffuse large B-cell lymphoma, and male breast cancer. In addition, studies of 8 other cancers showed inadequate evidence due to limited data, inconsistent results, or no data suggesting an association: cancers of the lung, esophagus (squamous-cell carcinoma), gastric noncardia, extrahepatic biliary tract, skin (cutaneous melanoma), testis, urinary bladder, and brain or spinal cord (glioma).

The investigators concluded sufficient evidence exists in experimental animals for a cancer-preventive effect of limitation of body-weight gain by caloric or dietary restriction for cancers of the mammary gland, colon, liver, pancreas, skin, and pituitary gland. In addition, they saw an inverse association between caloric or dietary restriction and cancer of the prostate, lymphoma, and leukemia.

—Mike Bederka

Reference:
Lauby-Secretan B, Scoccianti C, Loomis D, et al.; International Agency for Research on Cancer Handbook Working Group. Body fatness and cancer–viewpoint of the IARC Working Group [published online Aug. 24, 2016]. N Engl J Med. doi: 10.1056/NEJMsr1606602.