Malignant peripheral nerve sheath tumors - Prognostic factors and survival in a series of patients treated at a single institution

BACKGROUND. The authors explored the prognostic factors and clinical outcomes of patients who had malignant peripheral nerve sheath tumors (MPNST) with and without neurofibromatosis type I (NF-1). METHODS. Two hundred five patients with localized MPNST who underwent surgery at the Istituto Nazionale per lo Studio e la Cura dei Tumori (Milan, Italy) over 25 years were reviewed. Forty-six patients had concomitant NF-1 syndrome, and 159 patients did not. Local recurrence, distant metastases, and survival rates were studied. RESULTS. One hundred thirty patients presented with primary disease, and 75 patients had locally recurrent tumors. The disease - specific mortality rate was 43% at 10 years, with a continuously disease-free survival rate of no greater than 40%. Presentation with either primary or recurrent disease, tumor size, and tumor site (trunk vs. extremity) were the strongest independent predictors of survival. Margin status and radiation therapy also played a role, mostly related to their effect on local outcome. Pathologic grade influenced distant metastases, but only a trend for survival could be observed. No significant independent differences between patients with and without NF-1 were observed. CONCLUSIONS. To the authors' knowledge, this was among the largest single-institution series to date. The results confirmed that patients with MPNST share similar prognostic factors with patients who have other soft tissue sarcomas and have some of the worst clinical outcomes. The presence of NF-1 syndrome per se did not affect survival, but patients with NF-1 were more likely to have larger tumors. Therefore, such patients should be followed carefully to detect disease as early as possible.