Prior pregnancy ameliorates the course of intra-abdominal desmoid tumors in patients with familial adenomatous polyposis

PURPOSE: Intra-abdominal desmoid tumors occur in 12 percent of patients wit h familial adenomatous polyposis. A minority grow quickly and are lethal, m ost are relatively Inert, and some cause problems by obstructing adjacent o rgans. Desmoid tumors may be estrogen-dependant, and estrogen-blocking drug s are part of the usual treatment of these tumors. This study was performed to examine the effect of pregnancy on the course of patients with familial adenomatous polyposis and intra-abdominal desmoids. METHODS: All females w ith familial adenomatous polyposis and an intraabdominal desmoid treated or followed up at this institution were eligible. Stable, asymptomatic desmoi ds were followed up yearly with examination and CT scan. Growing or symptom atic desmoids were followed up at least every six months. Maximum tumor siz e was grouped as follows: <10 cm, 10 to 20 cm, and >20 cm. A change in tumo r size was defined as a change of +/-50 percent or more of maximum diameter . Stable tumors showed no change in diameter during the study period; varia ble growth was defined as a significant change in either direction that was followed by a return to previous dimensions or a stabilization of growth. Rapid growth was a doubling: of diameter within three months. Pregnant fema les were compared with nonpregnant females. Subgroups of females were match ed fur age at diagnosis of desmoid. RESULTS: Twenty-two females had net er been pregnant, whereas 25 had been pregnant at least once. Eleven pairs wer e matched for age. There were no differences between groups in the incidenc e of extracolonic manifestations of familial adenomatous polyposis, family history of desmoids, number or type of surgeries done for familial adenomat ous polyposis, length of follow-up, or time from surgery to desmoid diagnos is. Desmoids in pregnant females had a significantly more benign course: 18 were stable (vs. 6 nonpregnant females), 2 had variable growth (vs. 10), 1 had rapid growth (vs. 5), and 4 disappeared (vs. 1). There were also trend s to smaller, less symptomatic tumors requiring treatment less often in pre gnant females. CONCLUSIONS: Pregnancy seems to ameliorate the course of abd ominal desmoid tumors significantly in females with familial adenomatous po lyposis. This finding raises questions about the most appropriate hormonal treatment for these tumors. Perhaps progesterone or prolactin therapy shoul d be tried, alone or in combination with estrogen. If further studies confi rm these findings, females with a family history of desmoid tumors should n ot be advised against pregnancy.