Prognostic factors and treatment outcomes of malignant peripheral nerve sheath tumors (MPNST) of the extremities: A tertiary cancer institutional analysis.

Abstract

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon and aggressive ectomesenchymal soft tissue sarcoma that usually originates from peripheral nerves or pre-existing neurofibromas. These tumors are recognised for their high metastatic risk and challenging cases to treat. The purpose of this study was to analyse the factors impacting patient prognosis and treatment options by analysing treatment results and prognostic factors in patients with MPNST of the extremities. This retrospective longitudinal study included 53 patients with histologically and immunohistochemically confirmed MPNST of the extremities, treated at a tertiary care cancer centre from 2011 to 2018. Data were collected on demographics, clinical presentation, treatment modalities (surgery, radiotherapy, chemotherapy, palliative care), and follow-up. Follow-up included physical exams, imaging, and CECT thorax at 3-6 month intervals for two years, then biannually for three more years.Variables assessed for prognostic impact included age, sex, NF1 status, tumor grade, size, location, margin status, metastasis at diagnosis, and treatment intent. Disease-free survival (DFS) was measured from the date of surgery, and overall survival (OS) from the date of diagnosis. Among 53 patients with MPNST of the extremities, 52.83 % were over 45 years of age, and 63 % were male and 37 % were females. Most tumors (86.79 %) were sporadic, with NF1-associated tumors accounting for 13.20 %. Primary disease was more common (66.03 %) than recurrent (33.96 %). High-grade tumors were predominant, with 24.52 % classified as Grade 2 and 45.28 % as Grade 3. Metastatic disease was present in 20.75 % of cases. Tumor size was variable, with the largest proportion (32 %) in the 5-10 cm range. Curative treatment was administered to 67.92 % of patients, while 32.07 % received palliative care. Adjuvant radiotherapy was given to 35.64 % of patients, and chemotherapy (doxorubicin + ifosfamide) was administered to those with metastases. The overall survival rate was 58.46 %. Tumor grade (G2, G3), metastatic presentation, and intent of treatment were significantly associated with survival outcomes. NF1 status did not significantly impact overall survival, though NF1-positive patients benefited significantly from adjuvant radiation. Tumor grade was a strong predictor of survival, with Grade 3 tumors showing poorer outcomes than Grades 1 and 2. Our current study focuses on the predictive importance of treatment intent, tumor grade, and metastatic manifestation in patients with malignant peripheral nerve sheath tumors (MPNST) of the extremities. While variables such as age, gender, tumor size, surgical margin status, and NF1 status exhibited varying correlations, the most accurate predictors of survival were tumor biology, namely histological grade and metastatic occurrence.The cornerstone of curative treatment continues to be postoperative radiation after wide local excision with negative surgical margins. The results highlight the necessity of aggressive care and early detection, particularly in high-grade or NF1-associated patients.