Radiation treatment for aggressive fibromatosis: findings from observed patterns of local failure

We retrospectively evaluated the outcome of patients treated with radiotherapy, with or without surgery, for aggressive fibromatosis. The patterns of local failure were analyzed to determine the optimum radiation dose and volume for irradiation.

Twenty-four patients with histologically confirmed aggressive fibromatosis were treated with radiation therapy at the Yonsei Cancer Center between 1990 and 1998. The radiation dose per patient ranged from 39.6 to 59.4 Gy (mean: 49.4 Gy). The entire operative bed, with a generous margin, was included in the radiotherapy volume. Patients were considered as locally controlled if there was no evidence of the disease during their follow-up period, and if the tumors were stable for more than 2 years. The minimum duration of the follow-up period was 26 months, with a median of 69 months.

The actuarial 10-year recurrence-free and overall survival were 88.5 and 100%, respectively. Patients who had a recurrence were salvaged by combined surgery and re-irradiation. Recurrences developed only in patients who had a recurrent disease after surgery and were treated with an inadequate radiation volume. In 9 patients with a gross measurable disease, there were no in-field failures; these had been treated with a median of 50.4 Gy (range: 40-60 Gy) of radiation. Eight patients with a microscopic residual disease were also locally controlled with 41.4-59.4 Gy (median: 45 Gy) of radiation. No patient has developed either secondary malignancy or any serious radiation complications.

Radiotherapy for aggressive fibromatosis can be an effective treatment option for maintaining a disease-free status. As fibromatosis, with either a microscopic, or a gross residual disease, can be controlled with a moderate dose of radiation, adjuvant postoperative radiotherapy following surgical excision is recommended with the least sufficient margin to preserve good function and cosmesis. The geographic relationship may require a more precise definition; in addition, regardless of the existence of neighborhood normal tissue barriers, a wide coverage of the radiation volume may be needed.