This retrospective observational study aimed to investigate the perioperative outcome in Malignant Peripheral Nerve Sheath Tumors (MPNST) with and without relation to Neurofibromatosis Type 1 (NF1) and to detect possible prognostic factors.
We retrospectively reviewed 37 operated MPNST in 33 patients. Patient, tumor, and treatment characteristics were evaluated to identify prognostic variables.
Patients with NF1 were younger at the time of surgery (mean age: 29±13, 8-54 years) compared to sporadic cases (mean age: 45±13, 24-67 years) and exhibited larger tumor volumes (mean 299 vs. 18cm3). Most tumors were located in the facial/cervical/neck area (34%, n=12), followed by the trunk (31%, n=11), lower extremity (17%, n=6), upper extremity (14%, n=5) and intraspinal (3%, n=1). NF1-associated MPNST appeared predominantly on the trunk (39%) and sporadic in the facial/cervical/neck area (50%). R0 resection was possible in 66% and improvement or stability of function was achieved in most cases (motor 69%, sensory 74%) as well as a decrease in pain intensity (63%). In 12 cases with available 18F-fluorodeoxyglucose (FDG) PET, the mean preoperative standardized uptake value (SUV) (9.8±7.2) positively correlated with the mean maximum MIB-1 index (34±26%, p=.005), and the mean preoperative tumor volume (474.7±686.3cm3, p=.047). High-grade tumors exhibited more severe pain scores (median VRS scale 2, p=.002) and larger preoperative tumor volumes (mean 20.36cm3) compared to low-grade tumors (median VRS scale 0.5, mean vol 8cm3). Sporadic MPNST located at the head/facial/brachial plexus and upper extremities exhibited better preoperative functions compared to those on the lower extremities.
Early inclusion of PET diagnostics in clinical routine, especially for patients with NF1, is prognostically relevant. Surgery can improve symptoms, particularly medication-resistant pain, and should also be considered in advanced disease for symptom control/improvement.