Results of surgical treatment of patients with malignant peripheral nerve sheath tumors: a retrospective and prospective study

Background. Peripheral nerve sheath malignancies (PNSM) are a rare and aggressive group of sarcomas that can occur sporadically, after radiation therapy, or related to neurofibromatosis type 1. Loss of function of NF1, TP53, and CDKN2A genes is thought to contribute to the progression of benign neurofibroma to PNSM and is a poor prognostic sign. The optimal management of patients with this disease is currently unresolved, and specific prognostic factors have not been established. Aim. To analyze the results of surgical treatment in patients with PNSM and establish prognostic factors of overall and recurrence-free survival rate. Materials and methods. The retrospective and prospective studies enrolled adult patients with histologically confirmed PNSM treated between 1998 and 2021 at the N.N. Blokhin National Medical Research Center for Oncology. Surgical intervention was performed on 61 patients, 38 (62%) females and 23 (38%) males. The most common PNSM localization was paravertebral (22 [36%] patients), followed by retroperitoneal (14 [23%] patients), and upper and lower extremities (13 [21%] and 12 [20%] patients, respectively). Results. For PNSM patients with a history of surgery, the median overall survival (OS) was 46 months (95% confidence interval 26.165.9). The 3-year and 5-year OS was 46% and 31%, respectively. The median recurrence-free survival (RFS) was 27 months (8.745.3), and 3-year and 5-year RFS was 26% and 13%, respectively. Median OS for grade 1 malignancies was not achieved, while grade 2 and grade 3 malignancy was 53 and 33 months, respectively (p=0.033). The median RFS for grade 1, 2, and 3 tumors was 119, 43, and 15 months, respectively (p=0.078). Patients who underwent radical (R0) surgery had higher RFS (p=0.006) and OS (p0.0001). After radical (R0) surgery, the median OS was not achieved; after nonradical (R1/R2) surgery, the median was 34 months. The median RFS was 124 months after R0-resection and 48 months after R1/R2. Conclusion. The most significant prognostic factors in PNSM patients are the radicality of the surgery performed and the malignancy grade. In our study, tumor size and localization did not affect the long-term treatment results.