International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationsThe Role of Radiation Therapy in the Management of Dermatofibrosarcoma Protuberans
Introduction
Dermatofibrosarcoma protuberans (DFSP) is an uncommon, low-grade cutaneous sarcoma recognized for its aggressive local behavior, but low metastatic potential 1, 2, 3. The lesion presents typically during mid-adult life as a painless, nodular cutaneous mass, affecting men more often than women and occurring most often on the trunk, the head and neck area, or the proximal extremity 1, 3, 4, 5, 6. Although the histogenesis of this tumor is obscure, it has a distinct microscopic appearance characterized by fibroblast-like cells arranged in a storiform pattern [5]. At its periphery, the tumor is widely infiltrating 4, 5, 7. Surgical excision has generally been the treatment of choice for these lesions. However, local control after excision alone has often been less than satisfactory 1, 8, 9and multiple local recurrences predispose to distant metastasis 1, 6, 7, 10. The likelihood of local recurrence is related to the adequacy of surgical margins 4, 7, 8, 9, 11, 12, 13. Local failure rates have been reported to be 33–60% following conservative resection where the margins were either undefined or less than 2.5 cm 8, 9, 13. Wider excision margins have been reported to reduce the recurrence rate to 10–25% 1, 3, 4, 9, 10, 11. In selected patients, Mohs micrographic surgery may further reduce local recurrence rates 6, 9, 11, 14. Although the results with this technique have been promising, it is laborious and not well suited to large tumors.
An alternative approach is to use radiation in combination with surgery, as has been done for other soft tissue sarcomas 15, 16, 17. Radiation therapy offers a means for limiting the extent of resection and, hence, the morbidity associated with wide excision at some sites. Remarkably, the use of radiation therapy for DFSP has received little attention in the literature. Some reports have suggested that this disease is relatively radioresistant 1, 3, 4, but there is no convincing documentation for this contention. Indeed, local control has been reported when radiation was used as sole treatment for gross disease 2, 8, 18, 19. The principal reports on this subject have recommended radiation as an adjunct to excision 18, 19. The present series describes our experience at the University of Texas M. D. Anderson Cancer Center (MDACC) with radiation given primarily as an adjuvant to surgical resection.
Section snippets
Methods and Materials
Between 1972 and 1995, inclusive, 19 patients received radiation at MDACC, mainly as an adjuvant to surgical resection of DFSP. The pathologic slides were reviewed in our institution in all cases. For this retrospective study, we reviewed the hospital and radiotherapy charts to confirm the diagnosis, obtain presenting symptoms and signs and outline both the surgical and radiotherapeutic treatment techniques. Follow-up, dated from the completion of radiation, ranged from 6 months to 23.5 years
Results
The patient ages ranged from 19–76 years (median, 40 years); 12 (63%) were men. The anatomic distribution of lesions was: trunk, 8; head and neck, 7; and extremity, 4. Tumor size, specified as the largest linear dimension, was available in 16 patients and ranged from 1.2 to 15 cm (median, 4 cm). No patient had clinical evidence of lymphatic or hematogenous metastases at the time of the initial treatment at MDACC. Ten patients had experienced at least 1 recurrence prior to referral to our
Discussion
Surgical resection has long been the treatment of choice for DFSP 2, 3, 4, 6and, ultimately, eradicates the tumor in a large proportion of patients. However, DFSP is not easy to eradicate. The need for wide excision margins has been amply documented and is summarized in Table 2. It is generally recognized that conventional resection should encompass the tumor with at least 3 cm of margin, including underlying fascia 4, 6, 9, 10, 11but, even then, recurrence rates of 10–20% can be expected 9, 10
Acknowledgements
This study was supported in part by Grants CA 06294 and CA 16672 awarded by the National Cancer Institute, U. S. Department of Health and Human Services.
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