Limb salvage in soft tissue sarcomas involving neurovascular structures using combined surgical resection and brachytherapy

While there is debate in the literature concerning the tolerance of neurovascular structures to external beam radiation, the tolerance of these tissues to interstitial radiation has never been established. To evaluate the dose of radiation and its effect on early and late toxicity of neurovascular structures, a retrospective review of our experience was undertaken. Between 1975 and 1987, 299 patients with extremity sarcomas underwent limb-sparing surgery and tumor bed Iridium-192 interstitial implantation at Memorial Sloan-Kettering Cancer Center. Forty-five patients (15%) of this group were found to have locally advanced tumors involving major neurovascular structures. Of these patients, 64% had high grade lesions. Eleven percent had evidence of gross residual disease on these structures, and an additional 58% had microscopic residual disease at or close to the margins of resection. After loading catheters were placed directly upon the neurovascular structures in the exposed tumor bed and a median dose of 4400 cGy was delivered to the target volume. Eight patients had previous radiation to the treated field and 13 patients received postoperative radiation. With a median follow-up of 4 years, the 5-year actuarial disease-free survival was 69% and the 5-year actuarial freedom from in-field failure was 79%. The 5-year actuarial incidence of distant metastases was 30%. Eighty-four percent of the patients maintained long-term preservation of limb function without the need for amputation. Four patients (9%) ultimately developed evidence of radiation neuritis 6-20 months post therapy. All four patients had received additional radiation with cumulative doses exceeding 9000 cGy to the neurovascular bundle. We conclude that combined surgical resection and interstitial radiation for locally advanced sarcomas with neurovascular involvement can provide excellent local control with preservation of limb and neurovascular function without significant toxicity.