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Connective Tissue Oncology Society |
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| 2001 CTOS Annual Meeting Posters— Medical Oncology SUCCESSFUL TREATMENT
OF HIGH GRADE SOFT TISSUE SARCOMA WITH INDUCTION (NEOADJUVANT) CHEMOTHERAPY:
CLINICOPATHOLOGICAL ANALYSIS OF THICK CAPSULE FORMATION ALLOWING
LESS EXTENSIVE SURGICAL RESECTION OBJECTIVE: The histologic changes occurring in the periphery, or pseudocapsule, of sarcomas after induction chemotherapy have not previously been characterized in detail. We have used neoadjuvant chemotherapy in lieu of preoperative radiation therapy for limb sparing resections of large, high grade soft tissue sarcomas. Microscopic examination of soft tissue tumors that have responded well to induction chemotherapy demonstrates a thick, well defined “capsule” surrounding necrotic tumor. METHODS: During the period of 1988 to the present, over 60 resections for high-grade soft tissue sarcoma were performed by the same surgeon. Nearly half were eligible for enrollment in an induction chemotherapy protocol consisting of intravenous adriamycin, ifosfamide and intra-arterial cis-platinum. Resection specimens from ten patients were selected for histological analysis. Six of these were high grade tumors with median tumor necrosis of 94%. Two were high grade, poor responders (avg. 40% necrosis) and two were high grade not having undergone neoadjuvant treatment. Tumor types included MFH (3), liposarcoma (2), leiomyosarcoma (2), MPNST (1) and fibrosarcoma (1). RESULTS: In 5/6 patients with good therapeutic response, the tumor pseudocapsule was converted into an outer zone of densely collagenized fibrous tissue resembling a true “capsule” and an inner zone of loose vascularized fibrous tissue. The outer zone did not contain viable tumor cells. Untreated patients and poor responders demonstrated thin, interrupted and poorly defined outer zones and similarly vascular inner zones. CONCLUSION: Limb sparing resection for soft tissue sarcoma in the extremities often results in close surgical margins near critical neurovascular structures. Preoperative chemotherapy resulting in formation of a thick, collagenized capsule facilitates resection by forming a safe biological border for dissection. This treatment strategy may be considered analogous to induction chemotherapy in osteosarcoma, which has permitted an increased rate of limb salvage without increasing the rate of local recurrence.
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