[breadcrumb]
Heavy asbestos exposure has a link to gastrointestinal cancers, albeit not as strong of a link as with pleural and respiratory cancers.
Plenty of anecdotal examples exist illustrating how people heavily exposed to asbestos fibers during their job have acquired cancers of the stomach or GI tract. One such case study concerned a patient who worked in asbestos spinning factories and was heavily exposed over 25 years. He developed both lung cancer and gastric cancer.[1]
Another study estimated that there are around 15,500 cases of GI cancer identified within datasets for 12 occupations known to have higher-than-average incidence rates of mesothelioma.[2] The study calculated that the proportionate risk of esophageal, gastric, and colorectal cancer was much higher than the expected average rate.
A more-recent 2015 study examining 37 papers from 40 mortality cohort studies similarly found that the rates of stomach cancer were slightly elevated.[3] The study concluded that “exposure to asbestos is associated with a moderate increased risk of stomach cancer.”
Even the American Cancer Society recognizes that asbestos exposure may be linked to stomach, throat, colon, and rectal cancers but that “the link between these cancers and asbestos is not as clear as it is for the other cancers [like mesothelioma]”.[4]
The biggest issue with creating as strong of a link to asbestos exposure and GI cancer compared to respiratory cancers is that there’s no clear biological understanding of how these cancers can develop.[5] While researchers know that GI cancers can occur, they are unable to produce concrete evidence in the lab or in large statistical cohort studies.
For instance, dose-response in GI tissue samples is limited.[6] Dose-response measures whether development of a condition is more likely after heavier exposure. People exposed to more inhaled asbestos fibers are more likely to develop more-intense cancers, but the same response isn’t seen for GI cancers.
Overall, evidence linking asbestos to gastrointestinal cancer is abundant but inconsistent. Despite the connection not being completely clear, many medical professionals would attest that the link is well-documented and all but proven. Even the Agency for Toxic Substances and Disease Registry — in concurrence with the American Thoracic Society and National Toxicology Program — suggest screenings for GI cancers after the age of 50 if you have been previously exposed to asbestos.[7]
[1] https://aoemj.biomedcentral.com/articles/10.1186/s40557-015-0061-4
[2] https://www.researchgate.net/publication/14087567_Gastrointestinal_cancer_mortality_of_workers_in_occupations_with_high_asbestos_exposure
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647249/
[4] https://www.cancer.org/cancer/cancer-causes/asbestos.html
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856305/
[6] https://link.springer.com/article/10.1007/BF01314055
[7] https://www.atsdr.cdc.gov/csem/csem.asp?csem=29&po=12
