Small Study Shows Most Crohn's Patients With Anal Cancer Survived

ORLANDO -- While anal cancer is a rare complication of Crohn's disease, those who develop it do well with aggressive cancer treatment, according to a retrospective study that covered more than 2 decades of records.

Among 24 patients with Crohn's disease and anal cancer, 15 were alive with no evidence of disease at a median follow-up of 5.5 years after undergoing surgery or radiochemotherapy, reported Tanita Suttichaimongkol, MD, of the Mayo Clinic in Rochester, Minnesota, and Khon Kaen University in Thailand, during her poster presentation at the Advances in Inflammatory Bowel Diseases annual meeting.

Three others were alive with cancer, one participant was lost to follow-up, and the remaining five participants died, but their cause of death was unknown, Suttichaimongkol noted.

She and her colleagues also found that human papillomavirus (HPV) and long-standing perianal fistulas were potential risk factors for anal cancer in Crohn's disease patients.

Jakub Frey, MD, a gastroenterologist at Haukeland University Hospital in Bergen, Norway, told MedPage Today, "These are very encouraging findings, that such a high percentage of these anal cancer patients who also have inflammatory bowel disease have been cancer free for a long period. My understanding is that the mortality rate in this disease is much higher."

"We do not know if treatment with biologics, which can control inflammatory bowel disease, is helpful or harmful in patients with anal cancer," he told MedPage Today. "The biologics can tamp down the immune response of the body, and some of those cells may be responsible for attacking cancer cells."

"On the other hand, treatment with biologics can reduce inflammation, which also causes cancers to grow," he added. "Right now, I would think that biologics are beneficial in patients with both inflammatory bowel disease and anal cancer."

For this study, Suttichaimongkol and colleagues used data from electronic medical records of 24 adult patients (54.2% women) with Crohn's disease who were diagnosed with anal cancer and evaluated at the Mayo Clinic locations in Minnesota, Florida, and Arizona from January 1989 to August 2022.

Median age at diagnosis of anal cancer was 51 years (range 27-74). The median time from diagnosis of Crohn's disease to diagnosis of anal cancer was 18 years.

Eight participants were current smokers, and four were former smokers. Six patients had HPV.

Of the 24 participants, 18 were taking immunomodulators for their Crohn's disease prior to their anal cancer diagnoses, while 15 had been treated with biologic therapy.

Suttichaimongkol said that 11 participants sought further testing that led to cancer diagnoses when they experienced perianal fistula anal pain, four when they experienced Crohn's disease flares, and four when they experienced hematochezia. Two patients were concerned about finding perianal skin tabs, two were undergoing routine surveillance, and iron deficiency anemia triggered more testing in one participant. Sixteen of the cancers were discovered during anal examinations performed when participants were under anesthesia.

Stage I anal cancer was diagnosed in four participants, while stage II disease was diagnosed in nine, and stage III in 11.

Nineteen participants underwent surgery, 12 were treated with neoadjuvant radiochemotherapy, six were treated with adjuvant radiochemotherapy, and four were treated with adjuvant chemotherapy.

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