Treatment Outcomes and Sensitivity to Hormone Therapy of Aggressive Angiomyxoma : A Multicenter, International, Retrospective Study

Background: Aggressive angiomyxoma (AA) is a rare, locally aggressive tumor usually arising from pelvis or perineum, with a high local-recurrence rate after complete surgery. Anecdotal responses to hormone therapy have been reported. In the present study we aimed at studying surgical treatment outcomes and sensitivity to hormone therapy of AA. Materials and methods: We conducted a multicenter, international retrospective effort including patients with AA treated at three European referral centers (Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy and the Italian Rare Cancer Network; Centre Léon Bérard, Lyon, France; and Hospital Universitario Virgen del Rocio, Seville, Spain). Results: A total of 36 patients were included. Median follow-up was 51.3 months. Thirty-three patients (92%) underwent complete (R0 + R1) surgery, with a local relapse rate of 50% and a median relapse-free survival of 39 months (95% confidence interval [CI], 27-68.1). Thirteen patients received a first-line systemic treatment with hormone therapy for locally advanced disease, with an overall response rate of 62% and a median progression-free survival of 24.6 months (95% CI, 11.0-39.7). In two patients, adding an aromatase inhibitor (AI) on progression to first-line GnRH agonist (GnRHa) resulted in a new tumor response. Conclusion: Our findings confirm that in AA, surgical local control may be challenging, with a significant rate of local relapse despite complete surgery. Hormone therapy is an active treatment option, with a potential of disease control and of being combined with surgery. The addition of an AI to first-line GnRHa could be an effective second-line systemic therapy in premenopausal female patients with AA. Implications for practice: In this retrospective effort including 36 patients with aggressive angiomyxoma, local relapse rate after complete surgery was 50%, with a median relapse-free survival of 39 months, confirming that local control is challenging. Overall response rate to first-line hormone therapy was 62%, with a median progression-free survival of 24.6 months. Thus, hormone therapy has a potential of disease control and of being combined with surgery.