What is the prognosis of primitive neuroectodermal tumors (PNETs)?

Updated: Feb 07, 2019
  • Author: Carlo P Honrado, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The significant prognostic factors of peripheral primitive neuroectodermal tumors (pPNETs) include site, tumor volume, and the presence of metastasis. Kimber et al, in a review of 26 patients with pPNET who were treated with chemotherapy, reported that patients with head and neck pPNET had an intermediate prognosis when compared with patients with paraspinal and scapular disease (who fared better) and those with abdominopelvic disease (who fared much worse). [14] Because peripheral primitive neuroectodermal tumors (pPNETs) are highly aggressive, patients may have metastatic disease at presentation.

With reverse transcription polymerase chain reaction (RT-PCR) technology, several groups have demonstrated micrometastatic disease in the bone marrow of up to 30% of patients thought to have a localized disease. The most common sites of pPNET metastases include the lung, bone, and bone marrow. In several large series, the rates of metastases range from 20-31%, with abysmal long-term survival rates (< 25%).

Kushner et al, in a review of Memorial Sloan-Kettering's experience with pPNET, reported a similarly dismal 25% progression-free survival rate at 2 years in patients with only localized disease. [12] Other large series, however, reported somewhat better survival rates in patients with localized disease, with 2 large trials showing 2-year and 3-year survival rates of 65% and 56%, respectively. [10, 11]

A study by Jiang et al, using information from the Surveillance, Epidemiology, and End Results (SEER) Program database, indicated via multivariate analysis that age, tumor size, tumor stage, and whether or not the patient has undergone surgery affect cancer-specific survival (CSS) and overall survival (OS) for extraosseous and osseous Ewing sarcoma. Moreover, in osseous Ewing sarcoma specifically, CSS and OS were found to be significantly worse in patients who are non-White, diagnosed at an earlier age, and have an axially located tumor. In addition, multivariate analysis indicated that extraosseous Ewing sarcoma is associated with a worse prognosis than the osseous form. [15]

Again, with the diagnostic advances made in recent years, more accurate information regarding disease-free and long-term survival will be available in the future.

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