IBD disease and drugs are linked to Cancer
Inflammatory Bowel Disease (IBD) is a chronic condition characterized by inflammation of the digestive tract. While the exact mechanisms linking IBD to cancer are not fully understood, several key factors contribute to this increased risk.
Chronic Inflammation: The Root of the Problem
At the heart of the IBD-cancer connection lies chronic inflammation. In IBD, the immune system mistakenly attacks the digestive tract, leading to persistent inflammation. This inflammatory environment creates a fertile ground for cellular damage and genetic mutations.
How Inflammation Promotes Cancer
Oxidative Stress:
Inflammation generates reactive oxygen species (ROS), which can damage DNA. These DNA alterations can accumulate over time, leading to the development of cancer.
Immune Dysregulation:
The immune system plays a crucial role in cancer surveillance. Chronic inflammation can impair immune function, allowing abnormal cells to proliferate unchecked.
Genetic Instability:
Inflammation can trigger genetic mutations in intestinal cells, leading to uncontrolled cell growth and the potential for cancer development.
Epithelial Barrier Disruption:
The intestinal lining serves as a protective barrier. Inflammation can weaken this barrier, allowing harmful substances to enter the bloodstream and contribute to cancer risk.
Type of Cancer linked with IBD:
1. Colorectal cancer
CRC is one of the most common malignancies in patients with IBD and is a direct consequence of chronic colonic inflammation.
Other risk factors include:
- long disease duration,
- increased colonic involvement,
- family history of CRC and
- having primary sclerosing cholangitis.
2. Small bowel cancer
Patients with Crohn’s disease and small bowel inflammation are at an increased risk for small bowel adenocarcinoma and neuroendocrine tumors.
Additional risk factors include:
- tobacco use,
- male sex,
- childhood onset Crohn’s disease,
- long-standing small bowel inflammation,
- penetrating or stricturing disease and
- prior small bowel resection.
3. Intestinal lymphoma
Intestinal lymphoma is estimated to occur at a two- to three-fold increased in individuals with IBD compared with the general population.
These cancers occur more often in males, those with ongoing intestinal inflammation and in patients who have had Crohn’s disease for more than eight years.
4. Anal cancer
The absolute risk of anal cancer among patients with Crohn’s disease remains low, but higher than the general population. Additional risk factors include HPV and long-standing perianal fistualizing disease.
5. Extraintestinal malignancies
Cholangiocarcinoma is four times more likely to occur in patients with IBD compared with patients without IBD. Patients with primary sclerosing cholangitis are at the highest risk.
Patients with IBD are also at an increased risk for nonmelanoma skin cancers, hematologic malignancy and lung cancer.
Drugs used for IBD therapy are linked with some cancer:
1. Thiopurines
There is an increased risk of non-melanoma skin cancer at an almost two-fold increase.
Non-intestinal lymphoma is also an associated risk of thiopurine use as is genitourinary cancers.
2. Methotrexate
Data is limited, but studies show a small increased risk of non-melanoma skin cancer.
3. Anti-TNF
The data linking anti-TNF therapy with lymphoma and melanoma are conflicting. However, there is an increased risk of lymphoma when anti-TNF agents are combined with thiopurines.
4. JAK inhibitors
In IBD patients, there has been no data so far to suggest an increased risk of malignancy. However, clinical trial data for patients with rheumatoid arthritis on JAK inhibitors showed an increased risk of malignancy, particularly non-melanoma skin cancer, lung cancer and lymphoma.
5. Other biologics and small molecules
Current evidence does not show an increased risk of malignancy in patients with IBD treated with vedolizumab, ustekinumab, risankizumab, mirikizumab, ozanimod and etrasimod, although, long-term data are lacking.
Conclusion
IBD disease and drugs are linked to Cancer. While living with IBD can be challenging, it’s essential to prioritize regular check-ups and screenings.
By working closely with your healthcare provider, you can take proactive steps to manage your IBD and reduce your cancer risk. Early detection is key to successful treatment.
If you have IBD, discuss your cancer screening options with your doctor.