Malignant peripheral nerve sheath tumors (MPNST): the Mayo Clinic experience.

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are a rare form of soft tissue sarcoma with few studies reporting on patient outcomes and prognostic variables.

METHODS

A retrospective review of 175 patients diagnosed with MPNST from 1985 to 2010 was performed. Patient, tumor, and treatment characteristics were evaluated to identify prognostic variables.

RESULTS

The median age of our study population was 44 years, and 51% were female. Median tumor size was 6 cm, and 61% of patients had high-grade tumors. Tumors were most commonly located on the extremities (45%), then trunk (34%) and head/neck (19%). The majority of patients underwent surgical resection (95%) and adjuvant treatment with chemotherapy (6%), radiation (42%) or both (22%). Margin status was R0 in 69%, R1 in 2%, R2 in 9%, and unknown in 20%. The local recurrence rate was 22%, and 5- and 10-year disease-specific survival (DSS) were 60% and 45%, respectively. On univariate analysis, no predictors for local recurrence were identified. Tumor size ≥ 5 cm, high tumor grade, tumor location, presence of neurofibromatosis type 1, local recurrence, and adjuvant chemotherapy were all associated with DSS. On multivariate analysis, size ≥ 5 cm [hazard ratio (HR)= 6.1, 95% confidence interval (CI) 1.5-25.0], local recurrence (HR = 4.4, 95% CI 1.7-11.4), high tumor grade (HR = 3.8, 95% CI 1.1-13.2), and truncal location (HR = 3.7, 95% CI 1.1-12.7) were poor prognostic indicators for DSS.

CONCLUSIONS

High tumor grade and tumor size ≥ 5 cm predict adverse DSS for MPNST. In the context of a multidisciplinary treatment regimen, local recurrence and survival outcomes at 5 and 10 years were better than previously reported for MPNST.