Incidence, Prognostic Factors, and Survival in Malignant Peripheral Nerve Sheath Tumors: A SEER-Based Analysis (1975–2021)

Incidence, Prognostic Factors, and Survival in Malignant Peripheral Nerve Sheath Tumors: A SEER-Based Analysis (1975–2021)

Ali Abdolizadeh, Shelleen Gowrie, Michael Montalbano, Marios Loukas
St. George’s University, School of Medicine, St. George’s, Grenada

Rationale
Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive sarcomas accounting for ~5% of soft tissue malignancies, often with poor outcomes. Although previous SEER-based studies have evaluated MPNSTs, updated analyses are needed to capture current trends in incidence, survival, and prognostic factors.

Methods
MPNST cases (ICD-O-3-code 9540/3) were identified from SEER database (1975–2021). Age-adjusted incidence was calculated per 1,000,000 person-years. Survival was assessed using Kaplan-Meier and Cox models, stratified by surgery, stage, age, sex, location, and radiation.

Results
Incidence was higher in males than females (IRR=1.44, 95% CI:1.24–1.68, p<0.001), in Black individuals compared to White (IRR=1.18, 95% CI:1.02–1.37, p=0.03), and in those aged ≥45 compared to 0–24 years (IRR=3.20, 95% CI:2.83–3.62, p<0.001). Surgery improved survival (median: 60 vs. 8 months; HR=0.35, p<0.001), though not after adjusting for tumor stage (HR=0.812, p=0.683), which was the strongest predictor of survival (distant vs. localized: HR=12.57, p0.3). Pelvic and abdominal tumors had the highest mortality (surgery: HR=2.15;2.39, p<0.001; no-surgery HR=2.72;2.20, p<0.05). Radiation did not improve survival post-surgery (HR=0.89, p=0.211).

Conclusion
MPNST incidence remains low but is slowly rising, disproportionately affecting males, Black individuals, and older populations. Tumor stage and location strongly influence prognosis. Surgery improves survival primarily in localized disease, emphasizing the need for timely diagnosis, targeted epidemiologic monitoring, equitable healthcare policies ensuring access to early surgical care, and focused advocacy to address disparities in outcomes among vulnerable populations.

Keywords: MPNST, Survival, Prognosis, Surgery, Equity