What Is Colon Cancer?
In 2018, about 95,520 people in the U.S. were diagnosed with colon cancer and 39,910 people were diagnosed with rectal cancer.
Risk factors for developing the disease include being overweight or obese, physical inactivity, smoking, heavy alcohol use, having type 2 diabetes and family history of colorectal cancer.
Medical research on the relationship between colorectal cancer and asbestos is mixed. Some studies suggest a definitive cause and effect culminating in higher colorectal cancer rates among people who worked with asbestos. Other studies show little statistical basis for such a claim.
Colorectal Cancer and Asbestos Research
Occupational exposure to asbestos was the impetus for a major cancer study between 1984 and 2004. Experts looked at 3,897 patients who were exposed at work to asbestos. They then reviewed the potential link between asbestos and various specific cancers and found that colorectal cancer was elevated among men who were occupationally exposed to asbestos. Authors of the study said age, a history of smoking and other factors were adjusted in the results.
In 1994, a study published in American Journal of Epidemiology found asbestos workers exposed to amphibole asbestos were 1.4 times more likely to develop colorectal cancer.
In 1995, a study published in the same journal found male heavy smokers who were exposed to asbestos were 1.3 times more likely to develop colorectal cancer.
Another much older study of 632 insulation workers, an occupation well-known for asbestos exposure, yielded similar results. Workers who were evaluated entered the industry before 1943. Their health was monitored until 1962.
Authors of the study had expected 5.2 deaths, but data revealed 17 deaths were attributed to this cancer, suggesting that asbestos exposure increases the risk of developing colorectal cancers.
A 2019 research report reviewed over 40 cohort studies and concluded that the risk of colorectal cancer mortality increases as the level of asbestos exposure rises.
Other Studies Failed to Find Increased Risk
Despite scientific data supporting a link between colorectal cancer and asbestos exposure, conflicting studies suggest the opposite.
According to one report, published in International Archives of Occupational and Environmental Health in 1994, researchers studied 261 cases of colon and rectal cancer and 183 control cases in southeast Michigan. Workers from occupations with historically known asbestos exposure were analyzed.
The authors said the data did not support a finding of a causal relationship. They acknowledge that links between asbestos exposure and colorectal cancer exist in other studies and reports but found contradicting evidence within the context of their study.
In addition, researchers who performed an in-depth analysis of different published reports involving 20 groups of asbestos-exposed individuals found similarly interesting results.
The study, which was published in the American Journal of Epidemiology, found that one specific type of asbestos, amphibole asbestos, may potentially be associated with colorectal cancer, but may be as a result of an improper certification of cause of death. The authors reported data that suggests serpentine asbestos is not linked to an increased risk of colorectal cancer.
A 2006 review of 32 scientific studies the examined the potential connection between asbestos and colorectal cancer found no statistically significant causal relationship in the data.