An estimated 10% to 20% of the individuals with familial adenomatous polyposis (FAP) will develop desmoid tumors. Desmoids are benign growths of fibrous tissue that form either spontaneously or after surgery. They are more common in females and develop primarily, but not exclusively, in the abdomen. While not malignant, desmoids can be large and aggressive and compress abdominal organs. Standard treatments include surgery, radiation, chemotherapy, corticosteroids, and anti-inflammatory and anti-hormone medications. Surgery is the treatment of choice but is not always an option if the tumor is too close to major blood vessels or other organs.

Dr. Noralane Lindor and her staff at the Mayo Clinic in Rochester, MN, are conducting a small clinical study of a new investigational drug called pirfenidone for treatment of desmoid tumors in individuals with FAP. Pirfenidone was selected because it is a broad-spectrum antifibrotic agent. It is thought to be the first agent capable of stopping the growth of fibrous tumors as well as reducing long-standing fibrous tumors. Prior to this study, no patients with desmoid tumors have been treated with pirfenidone, and it is not known whether or not this medication will actually have an effect. The study began in 1998 and will continue until 2000.

The risk of developing desmoid tumors is 852 times greater in individuals with FAP than in the general population. Even if surgical removal is possible, the rate of recurrence is high. Combinations of various chemotherapeutic agents or anti-hormone and anti-inflammatory agents have been marginally successful in management of desmoid disease. The lack of an effective treatment underscores the need for new drug development and continued clinical studies.