Purpose: To explore prognostic factors in surgically treated aggressive fibromatosis (extra-abdominal desmoid tumor).
Patients and methods: A total of 203 consecutive patients treated with surgery over a 35-year period at a single referral center were retrospectively reviewed. One hundred twenty-eight were first seen at our institution with primary disease, whereas 75 had a recurrent tumor. All patients underwent macroscopically complete resection. Margins were rated as negative in 146 (97 with primary tumors, 49 with recurrences) and positive in 57 (31 in primary, 26 in recurrences) patients. Median follow-up was 135 months.
Results: Patients with primary disease had a better disease-free survival rate than those with recurrence (76% v 59% at 10 years). Presenting with a recurrence was also the strongest predictor of local failure in the multivariate analysis. In patients first treated for primary disease, size and site had prognostic significance, whereas microscopically positive surgical margins did not. In contrast, in patients with recurrence, there was a trend toward better prognosis if margins were negative (although this was not significant at multivariate analysis).
Conclusion: Presence of microscopic disease does not necessarily affect long-term disease-free survival in patients with primary presentation of extra-abdominal desmoid tumors. Thus, function-sparing surgery may be a reasonable choice when feasible without leaving macroscopic residual disease. In patients with recurrences, positive margins may more clearly affect prognosis, potentially necessitating adjuvant radiation in selected cases.