By Brett Spiegel
If living with inflammatory bowel disease (IBD) wasn't hard enough, patients with the digestive disorders Crohn's and colitis may be at an elevated risk for developing skin cancer too, according to research presented at the Digestive Disease Week conference in Orlando.
Researchers at Mayo Clinic discovered the correlation between IBD diagnoses and an eventual diagnosis of melanoma, a very serious form of skin cancer often attributed to sun exposure. An analysis of seven years worth of published studies about IBD uncovered about 180 cases of melanoma diagnosed in 170,000 patients who already had IBD (roughly 90,000 with Crohn's disease and 80,000 with ulcerative colitis). The U.S. Centers for Disease Control and Prevention report that over 60,000 people were diagnosed with melanoma in 2009, of which about 9,000 died.
"Even though we included both population- and clinic-based studies ... which are at minimal risk of selection bias and more generally applicable, the increased risk of melanoma continued to be significant," the researchers write in the review. The Mayo findings suggest that having IBD puts patients at a 37 percent rate of being more likely to develop melanoma.
The analysis identified only a correlation — an association between two factors that doesn't necessarily prove that one is responsible for the other — between melanoma and IBD, not a causal connection.
In a recent column discussing correlation studies associating skin cancer to Alzheimer's and other conditions, Everyday Health leader Adam Friedman, MD, cautioned that, while correlation studies provide useful information, they often find only common threads, not strong connections. "[I]t is understandable to look under every rock for possible advances in our ability to prevent, diagnose, and treat affected individuals," Dr. Friedman wrote. "Population-based research is often used to try to identify commonalities between different diseases states, risk factors, or possibly even protective factors."
And, he added, some diseases may have characteristics that could increase cancer risks. "[I]n any setting where there is relentless inflammation, cancer is always a risk as repair or restorative mechanisms which swoop in after the inflammation wreaks havoc may fail, resulting in ongoing growth of damaged or cancerous cells," Friedman said in an email.
The Mayo research stresses the need for IBD patients to take preemptive measures in deceasing their chance for developing skin cancer and to see a doctor if they believe they could be at risk. "Based on this data, we are suggesting that physicians appropriately counsel IBD patients about the risk of melanoma," said study author Siddharth Singh, MBBS, a Mayo Clinic gastroenterologist, in a press release. "Sun-protective measures are very effective in preventing this cancer."
Unlike irritable bowel syndrome (IBS) — a condition that shares symptoms with IBD, such as abdominal pain and cramps, bloating, excessive diarrhea, and constipation — IBD conditions like Crohn's disease and ulcerative colitis are much more serious. IBD affects as many as 700,000 Americans, according to the Crohn's & Colitis Foundation of America. Patients with Crohn’s disease experience painful ulcers in both their small and large intestines in addition to occasional rectal inflammation and bleeding. Ulcers form in both the rectum and the large intestine in those with ulcerative colitis.
"IBD and Melanoma: Mayo Researchers Find a Correlation" originally appeared on Everyday Health.