Does IBD Increase Risk for Oral Cancer?
Patients with inflammatory bowel diseases (IBD) have an increased risk of oral cancers—especially tongue cancer—researchers report in the March issue of Clinical Gastroenterology and Hepatology. Women are at higher risk than men.
Oral cancers develop in the mucosal surfaces of the lips, floor of mouth, tongue, buccal mucosa, lower and upper gingival, hard palate, and retromolar trigone. Most cases originates from the squamous epithelium.
Risk factors include tobacco and alcohol consumption, as well as nutritional deficiencies, viruses such as human papilloma virus (HPV), chronic irritation, genetic factors, and immunosuppression or immunodeficiency. Many of these factors are also associated with IBD risk. Konstantinos H. Katsanos et al performed a retrospective study to determine the incidence of oral cancer in 7294 patients seen at the Mount Sinai Medical Center (NY), from 2000 through 2011.
Katsanos et al observed an excess risk of oral cancer in patients with IBD: women had a 12-fold increase in risk and men had an 8-fold increase, compared to the general US population (based on the Surveillance, Epidemiology and End Results registry).
The authors identified 11 patients (7 men) in the IBD cohort with biopsy-proven oral cancer. The diagnosis of oral cancer was made after the diagnosis of IBD in all patients, at a mean of 17.6 years after the diagnosis of IBD. The mean age of the group of patients with IBD at oral cancer diagnosis was 44.6 ± 17.4 years, and 4 of 11 patients were younger than 50 years at the time of the oral cancer diagnosis
Katsanos et al also found a significantly increased incidence of tongue cancer in patients with IBD—an age-adjusted standardized incidence ratio of 18. This ratio was 22 in women and 17 in men with IBD.
Four of the 11 patients who developed oral cancers were heavy smokers and 3 were alcohol abusers. Seven of the patients were receiving medical treatment for their IBD (azathioprine or mercaptopurine, anti-tumor necrosis factor (TNF), or mesalamine) before their cancer diagnosis.
In patients with IBD, exposure to thiopurines has been associated with an increased risk of lymphomas, nonmelanoma skin cancers, and urinary-tract cancers. However, previous studies have shown that in patients with IBD and a history of cancer, exposure to an anti-TNF agent or an anti-metabolite after cancer is not associated with an increased risk of incident cancer, compared with patients who do not receive immunosuppression.
Katsanos et al state that further studies are needed to determine whether immunosuppressive therapies (such as azathioprine and anti-TNF) are risk factor for oral cancers.
IBD has been associated with neoplastic lesions of the uterine cervix.
What happened to the patients with oral cancer in the cohort of Katsanos et al? The oral cancer progressed or recurred in only 2 patients, and 91% of the patients survived for 5 years (1 of the 11 patients died, after 3 years). Outcome correlated with tumor size and spread to lymph node at the time of diagnosis.
Katsanos et al state that although this is the largest study of oral cancer in patients with IBD, there was a risk for referral center bias. Calculated risk could have been overestimated and these results might not apply to the average population of patients with IBD.
Despite these limitations, these findings provide a good starting point for studies of the incidence, risk factors, and long-term outcomes of oral cancer in patients with IBD. They also create a basis for recommendations regarding oral cancer surveillance, therapy, and prevention.