Extra-abdominal desmoid fibromatosis: An evaluation of clinical factors affecting local recurrence rates

The aim of this study was to determine the prognostic factors for recurrence in patients with extra-abdominal desmoid tumors (EDTs) treated surgically.

This single-institution, retrospective study included patients with a histologically-proven extra-abdominal desmoid tumor between 2007 and 2018. The demographic characteristics (age, sex) of the patients, tumor characteristics (region, size, proximity to neurovascular structures, margins), treatment management (surgery and/or adjuvant radiotherapy), and clinical results were analyzed. The effects of these possible prognostic factors on overall and disease-free survival rates and the risk of local recurrence were evaluated.

Evaluation was made of 22 patients (16 females, 6 males) with a mean age at diagnosis of 34.7 years (range = 22-76 years). The mean follow-up was 104 months (range = 4.8-168). Tumor localization was in the upper extremity in 4 patients (18.1%), the lower extremity in 11 (50.0%), and the trunk in 7 (31.8%). The mean tumor size (maximum diameter) was 5.2 cm (range = 0.6-13 cm; median = 5.8 cm), and the mean tumor volume was 181.3 ± 531.4 ml. All the 22 patients were treated surgically along with adjuvant radiotherapy (RT) administered to 8 in addition to surgery for the primary treatment of the tumor. Following primary surgery, resection margins were R0 in 11 patients, R1 in 9 and R2 in 2. Local recurrence (LR) developed in 6 patients (27.2%) during the follow-up period. Recurrence-free survival rate (RFS) was 90.9% at one year, 74.1% at 5 years, and 61.7% at 10 years. During the follow-up, no patient died, and distant metastasis was not detected. Tumor length, resection margins, and adjuvant RT were observed to influence the risk of local recurrence (P < 0.05).

The results of this study have demonstrated that tumor size ≥ 5 cm and the presence of microscopic or macroscopic positive surgical margins can increase the risk of LR, and adjuvant RT can reduce the development of LR in the management of EDT.