Abstract Malignant peripheral nerve sheath tumor (MPNST) are a rare and aggressive cancer that make up 5-10% of all sarcomas. There is currently no effective targeted therapy to treat MPNST and surgical resection remains the mainstay of treatment, though often not feasible due to location, size of the tumor, or presence of metastases. Evaluation of MPNST treatment response to palliative chemotherapy regimens could serve as a reference point for target response rates in clinical trials going forward. We performed a retrospective electronic health record analysis of patients with biopsy-proven diagnoses of MPNST at Washington University and Johns Hopkins University. We evaluated tumor characteristics along with treatment response, overall survival (OS), and progression free survival (PFS) rates for different chemotherapeutic regimens. The cohort comprises 140 patients, with ages at diagnosis ranging from 21 to 40 years. Most patients had tumors located in the extremities, with sizes ranging from 5-10 cm at the time of diagnosis. We identified 66 patients who received adjuvant chemotherapy, 44 received neoadjuvant chemotherapy and 28 did not receive any chemotherapy. We will present objective response rate (ORR) and clinical benefit rate (CBR) for neoadjuvant chemotherapy. Among patients with metastatic disease (n=53), 12 chemotherapy regimens were assessed. All regimens other than gemcitabine-docetaxel chemotherapy regimen performed better than the median PFS of 1.77 months which has been observed in clinical trials of targeted agents to date with the most compelling response to vincristine-irinotecan-temozolomide regimen. Despite advancements in our understanding of MPNST pathogenesis, these tumors carry a poor prognosis. Our study has identified several systemic therapies which should be further evaluated prospectively to improve treatment options and outcomes for patients with this aggressive sarcoma. These results can serve as a benchmark for future clinical trials.
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