Radiotherapy is effective for desmoid tumors (aggressive fibromatosis) - long-term results of a German multicenter study.

Background: Desmoids (aggressive fibromatosis) are defined as benign neoplasms of the connective tissue that arise from the deep muscle fascia, aponeurosis, tendons, and scar tissue. Recurrence rates between 40 and 80% were reported after surgery alone. We addressed the impact of radiation therapy (RT) in the management of aggressive fibromatosis.

Patients And Methods: A large literature review was performed, and the data was compared with the results of a multicenter study of the German Cooperative Group on Radiotherapy for Benign Diseases (GCG-BD).

Results: This analysis included 52 patients treated with RT. 37 patients received postoperative RT (20 patients after R2 resection and 17 patients after R1 resection). 15 patients received RT alone (6 patients with inoperable primary tumor and 9 patients with inoperable recurrent tumor). In the case of postoperative RT, a median dose of 50 Gy (range 50-60 Gy) was used; for definitive RT, a median dose of 55 Gy (range 55-65 Gy) was used. The local control rate was 79% for the whole group. The median follow-up was 44 month (range 8-62 months).

Conclusion: Given the large number of patients, these data show that RT is highly effective in the treatment of desmoid tumors. RT is an attractive alternative to mutilating surgery.