Patients living with inflammatory bowel disease (IBD) have a greater risk of developing melanoma, Mayo Clinic researchers say.
The findings were presented at the Digestive Disease Week 2013 conference in Orlando, Fla., showing that found IBD could pose a 37 percent higher risk for developing skin cancer.
IBD is broadly used to describe inflammatory responses in the gastrointestinal tract, according to the Centers for Disease Control and Prevention. The most common IBDs are ulcerative colitis (UC) and Crohn's disease, which share similarities in how the immune system abnormally responds to infections by inflaming the intestinal lining that leads to issues including watery diarrhea, rectal bleeding, abdominal pain, fever, and weight loss.
In their study, researchers recruited 172,837 patients with IBD and extensively reviewed IBD publications within the past seven decades to uncover 179 reported cases of melanoma after being diagnosed with IBD.
The study was also published earlier this month in Clinical Gastroenterology and Hepatology, offering insight to patients with the condition so they may consult doctors for preemptive measures to reduce their chances of skin cancer.
"Based on this data, we are suggesting that physicians appropriately counsel IBD patients about the risk of melanoma. Sun-protective measures are very effective in preventing this cancer," said study author Siddharth Singh, M.B.B.S, a Mayo Clinic gastroenterologist.
The body's immune system plays a tireless role in regulating both IBD and melanoma, and in some cases medication could be a problem. Research has shown that using immune-suppressing medications like thipurines could raise risk of nonmelanoma skin cancer, so patients are told to protect their skin and keep an eye out for changes. In some cases, undergoing skin exams could help monitor skin cancer.
Investigators have also found that a malfunction in the immune system could initiate changes to the gut's intestinal bacteria and cause IBD. Certain sensors are responsible for regulating the microbiota in the gut to keep IBD at bay, so a glitch in system could remove these special sensors to trigger IBD.
Advances have been made to treat IBD. Previous studies spotted a potential molecule, called peroxisome proliferator-activated receptor-gamma, in the immune system itself that could control the unwarranted inflammation in the gut.
For cancer, investigators found the immune system could play a larger role than before to combat tumors. Two newly developed drugs, yervoy and nivolumab, succeeded in shrinking tumors in nearly 41 percent of melanoma patients they studied.
Cancer cells normally stop T-cells from attacking them, but the drugs were able to restrict the immune system that control T-cells and unleash them to fight the tumors.
Researchers believe that melanoma could be a starting target for treating other cancers because of how it's often regulated by the immune system.
IBD has also been linked to basal cell carcinoma and squamous cell carcinoma specifically, if the patients use thiopurines.
In the United States, more than 1.5 million people have either Crohn's disease or UC. The direct health care costs associated with IBD are estimated at $15 billion every year.