Is there an increased risk of malignancy in patients with inflammatory bowel diseases?
Inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis, can potentially increase the risk of malignancy, both due to the chronic inflammation in the intestines and as a result of the treatments given to manage the diseases. However, the word "cancer" often triggers fear due to lack of knowledge. I'll try to provide a brief overview of the topic and assess the level of risk, as knowledge reduces anxiety and enables informed treatment decisions. Of course, what's written here does not replace an honest and open conversation with your treating physician at all stages of treatment. Such discussions help you understand and weigh the benefits of treatment against possible side effects.
Does the inflammation itself pose a risk of malignancy?
Any chronic inflammation in the body, including the intestines, poses a risk of malignancy. The location of malignancy in the intestines is closely linked to the location of inflammation - whether in the small or large intestine. While there is a small increase in the risk of small intestine cancer in patients with Crohn's disease affecting this area, it is relatively rare. Less rare is colon cancer when inflammation is present in the large intestine (either as a result of ulcerative colitis or due to Crohn's disease involving the large intestine). Therefore, we recommend a colonoscopy every 1-3 years starting from 8-10 years of disease in the large intestine to detect pre-cancerous changes microscopically. It seems that this close monitoring contributes to reducing the risk of malignancy by enabling early detection. In any case, it's advisable to avoid smoking and ensure a fiber-rich diet. Especially important is complete calming of inflammation through medication to further reduce the risk directly related to the severity of inflammation over time. On the other hand, the disease itself does not usually significantly elevate the risk of lymphoma (blood cancer) or other extraintestinal malignancies.
Do medical treatments increase the risk of malignancy?
Most medications for inflammatory bowel diseases are immunomodulators, and some of them have a certain contribution to the risk of malignancy. The most known is thiopurine (Imuran), and its counterpart purinethol, which slightly increases the risk of lymphoma (blood cancer), although this complication is not very common. It's a bit like buying four lottery tickets. The chances of winning increase by a factor of four, but they still remain low. The risk may slightly increase when thiopurine is combined with biologic drugs, but this needs to be balanced against the effectiveness of the treatment. Biologic drugs also slightly elevate the risk of skin cancer and possibly cervical cancer. All at low rates, but it's advisable to avoid sun exposure without high protection sunscreen and use appropriate clothing. It's recommended for girls to get vaccinated against the HPV virus. It's important to remember that these medications are highly effective in maintaining long-term remission in inflammatory bowel disease. Therefore, the chances of needing steroid treatment (with all its associated side effects), surgeries, and hospitalizations become smaller. Moreover, although these medications may slightly increase the risk of extraintestinal malignancies, they also reduce the incidence of colon cancer related to chronic inflammation, as mentioned above.
In summary, the excess risk of malignancy associated with Crohn's disease and ulcerative colitis and their treatments is small. When looking at the big picture, the benefits of immunomodulator medications outweigh the risks, as long as the medication is given with the appropriate prescription and close follow-up in experienced centers. Individual discussions with the treating physician should take place before making any treatment decisions.