Obesity is a known risk factor for colorectal cancer. The scientists of the German Cancer Research Center (DKFZ) have now shown that this association has probably been significantly underestimated so far.
Obesity is a risk factor for a whole range of cancers. This association is particularly evident, for example, in the case of endometrial, kidney and even colorectal cancer. According to previous estimates, obese people have a risk of developing colorectal cancer that is about a third higher than that of people of normal weight.
“However, these studies have so far failed to take into account the fact that many affected people lose weight in the years prior to being diagnosed with colorectal cancer.”, says Hermann Brenner, an epidemiologist and prevention expert at the German Cancer Research Center. “This has led to a significant underestimation of the risk contribution of obesity in many studies..
From the data, a strong correlation was found between being overweight and the likelihood of developing colorectal cancer, which was most pronounced 8 to 10 years before diagnosis. Study participants who were severely overweight — referred to as obese — during this period were twice as likely as those of normal weight to develop colorectal cancer. In their analyses, Prof. Brenner was able to identify another trend: A staggering number of study participants with colorectal cancer had lost weight unintentionally before their diagnosis.
Unintentional weight loss of two pounds or more within two years before diagnosis (or study entry) occurred 7.5 times more frequently in individuals with cancer than in the control group. “During this time, the cancer is already present, but not yet visible by symptoms. Physicians should therefore regularly ask their patients about unintentional weight lossBrenner appeals, adding:Unintentional weight loss could also be an early indication of other cancers or other diseases and should be carefully clarified.”
Read the full text of the article:
Association of Overweight, Obesity, and Recent Weight Loss With Colorectal Cancer Risk.
Mandic M, Safizadeh F, Niedermaier T, Hoffmeister M, Brenner H.
JAMA Netw Open. 2023;6(4):e239556. doi:10.1001/jamanetworkopen.2023.9556
Source: German Cancer Research Center