RÉSUMÉ
BACKGROUND: The role of both hormonal contraception and pregnancy on the outcomes of desmoid-type fibromatosis (DF) is debatable. MATERIALS AND METHODS: In the present study, we selected female patients of childbearing age from the prospective ALTITUDES cohort. The primary study endpoint was event-free survival (EFS), with an event defined as relapse or progression. We estimated the risk of events according to the use of hormonal contraception [estrogen-progestin (EP) and progestin] and pregnancy status using multivariate time-dependent models, controlling for major confounders. RESULTS: A total of 242 patients (median age, 34.7 years) were included in the present study. The abdominal wall was the most common tumor site (51%). Patients were managed by active surveillance (80%) or surgery (20%). Pregnancy occurred within 24 months before, at the time of, and after DF diagnosis in 33%, 5%, and 10% of the cases, respectively. Exposure to hormonal contraception was documented within 24 months before, at the time of, and after diagnosis in 44%, 34%, and 39% of the cases, respectively. The 2-year EFS was 75%. After adjusting for DF location, tumor size, front-line treatment strategy, and hormonal contraception, we observed an increased risk of events occurring at 24 months after pregnancy [hazard ratio (HR) = 2.09, P = 0.018]. We observed no statistically significant association between the risk of events and current EP exposure (HR = 1.28, P = 0.65), recent EP exposure (within 1-24 months, HR = 1.38, P = 0.39), current progestin exposure (HR = 0.81, P = 0.66), or recent progestin exposure (HR = 1.05, P = 0.91). CONCLUSIONS: In our study, a recent history of pregnancy was associated with an increased risk of progression/relapse in patients with newly diagnosed DF, whereas hormonal contraception did not demonstrate an association with progression/relapse.