American Society for Peripheral Nerve

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Neurofibromatosis-Associated Malignant Peripheral Nerve Sheath Tumors in Children Have a Worse Prognosis: a Nationwide Cohort Study
Enrico Martin, MD1, J. Henk Coert, MD, PhD1, Dirk-Jan Grunhagen, MD, PhD2 and Cornelis Verhoef, MD, PhD2, (1)University Medical Center Utrecht, Utrecht, Netherlands, (2)Erasmus Medical Center, Rotterdam, Netherlands

Background: Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive non-rhabdomyoblastic soft tissue sarcomas (NRSTS) in children. More can be learned about prognostic factors on survival in pediatric MPNSTs as it may help tailoring clinical decision-making. This study set out to investigate differences in clinical presentation between adult and pediatric MPNSTs as well as neurofibromatosis type 1 (NF1) and non-NF1 pediatric patients. Overall survival, treatment modalities, and factors associated with survival were evaluated using a Dutch nationwide cohort of patients.


Methods: Data were obtained from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Database (PALGA). All pathologically confirmed primary MPNSTs were collected. Patient and tumor characteristics, time period (based on the 2006 publication of chemotherapy trials in pediatric MPNST), treatment modalities, and survival were extracted from the database and pathology reports. Demographical differences were analyzed between adult and pediatric (age ≤18 years) MPNST. Demographical and treatment differences between NF1 and non-NF1 were also analyzed. A Cox proportional hazard model was constructed for localized pediatric MPNSTs.


Results: A total of 784 MPNST patients were registered of which 70 were children (37.1% NF1). No significant demographical differences were present between children and adult cases. In children, most tumors were large (>5cm, 71.4%), and deep-seated (under the fascia, 86.0%). Six non-NF1 patients presented with synchronous metastases (8.6%). Tumor size were more commonly large in NF1 patients (92.3% vs. 59.1%, p = 0.05). No statistically significant differences were observed for treatment modality between localized NF1 and non-NF1 patients. Localized disease was resected in 90.6%; R0 resection was achieved in 66.7%. Radiotherapy and chemotherapy were administered in 37.5% and 34.4% respectively. Non-NF1 patients tended to receive chemotherapy more commonly compared to NF1 patients (39.5% vs. 26.9%, p>0.05). Overall, estimated 5-year survival rates of localized pediatric MPNST was 66.3% (SE: 6.0%), which was lower in NF1 (52.4%, SE: 10.1%) compared to non-NF1 patients (75.8%, SE: 7.1%, p<0.05). The multivariate model showed worse survival in NF1 patients and increased survival in patients diagnosed after 2005 (both p<0.05). No treatment factors were independently associated with survival.


Conclusion: Pediatric MPNST present similarly compared to adult MPNST. In children, NF1 patients will generally present with larger tumors, but are treated similarly compared to non-NF1 MPNSTs. In localized pediatric MPNST, NF1 status is independently associated with poor survival. No treatment related factor was independently associated with survival. Also, life expectancy has increased for pediatric MPNSTs after 2005.


Figure 1

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