(P 518) OUTCOMES OF NON-ANGIOSARCOMA RADIATION-ASSOCIATED SOFT TISSUE SARCOMAS OF THE CHEST

Objective: Radiation-associated soft tissue sarcomas (RA-STS) are a rare complication of patients receiving radiation therapy and are generally associated with a poor prognosis. Most of the literature surrounding RA-STS of the chest is centered on angiosarcoma. Therefore, we aim to document the management and outcome of patients with RA-STS in the chest wall, specifically non-angiosarcoma lesions.

Methods: We conducted a retrospective review of 18 patients from a single institution diagnosed with RA-STS between 1972-2011. RA-STS was defined as a histologically confirmed soft-tissue sarcoma of the chest in a previously irradiated field with a minimum 5-year interval between radiation for the primary tumor and the diagnosis of the sarcoma. All patients underwent surgical resection with curative intent and, for survivors, had at least 12 months follow-up. Exclusion criteria included non-operative treatment and palliative surgical treatment. The outcome measures were local recurrence-free and metastasis-free survival as well as post-operative complications. Perioperative death was defined as intraoperative death or death within 90 days of the index surgery.

The prior malignancies included breast (83%), multiple myeloma (6%), lymphoma (6%), and acute lymphocytic leukemia (6%). All patients underwent radiation treatment for their primary malignancy and dose information was available for 5 patients (mean dose 50 Gy. The median time to secondary malignancy diagnosis was 15 years. The histological diagnoses of RA-STS were undifferentiated pleomorphic sarcoma (72%), fibrosarcoma (11%), malignant peripheral nerve sheath tumor (6%), chondroblastic extraskeletal osteosarcoma (6%), and pleomorphic liposarcoma (6%). Five patients (27%) received chemotherapy, and five patients (28%) received combined treatment with radiation for their metastases. More patients received dual agent chemotherapy (i.e.,etoposide/ifosfomide, gemcitabine/taxotere, ifosfamide/doxorubicin (60%) than with three agents (i.e. methotrexate, doxorubicin, cisplatin; (20%) or four agents (i.e., doxorubicin, gemcitabine, ifosmamide, etoposide; (20%).

Results: All patients were treated surgically. Fourteen patients (78%) underwent wide local excision and four underwent forequarter amputation (22%). Median largest tumor dimensions were 4.8 cm). One patient was positive for 2 foci of tumor at the sternal bony margin, the largest of which measured 8 mm (R2, (6%)). All other patients presented negative margins (R0, n=17 (94%)). Nine patients experienced perioperative surgical complications. Most common reasons for complications were wound-related, including 2 infections and 3 dehiscences. Seven patients (39%) developed local recurrence at a median of 13 months. Three patients (43%) were treated with surgical resection and four (57%) were managed with cryoablation, forequarter amputation, radiation therapy, and chemotherapy with ifosfamide and doxorubicin. While six patients (33%) developed metastases at a median 12.5 months. All six patients acquired metastatic lesions in their lungs, while three of them attained additional lesions in the iliac lymph nodes, right arm, and soft tissue of the neck. Recurrence-free survival at 1 and 5 years was 72% and 50% respectively (Fig. 1). There were no recurrences beyond 19 months from surgery. Disease-specific survival at 1 and 5 years was 89% and 57% respectively (Fig. 2).

Conclusion: Non-angiosarcoma RA-STS involving the chest wall presents a challenging disease process, with surgical management having a high-rate complications. Aggressive surgical management should be considered for patients, as with local control patients can have outcomes similar to patients with Stage IIIB soft-tissue sarcomas.