Gamma Knife Surgery for Recurrent or Residual Supratentorial Primitive Neuroectodermal Tumors

Abstract

Background: Supratentorial primitive neuroectodermal tumors (PNETs) are highly malignant and rare tumors of the central nervous system. Objectives: The aim of this study was to determine the role of Gamma Knife surgery (GKS) as a salvage treatment option for patients with recurrent or residual supratentorial PNETs. Methods: Between 1998 and 2014, 11 patients with supratentorial PNETs were retrospectively analyzed. This series consisted of 7 male and 4 female patients. The median age was 17 years. All patients received surgical resection followed by adjuvant therapy. The median time from operation to the first GKS treatment was 72.5 months. The median tumor volume was 17.5 cm³, and the median marginal dose was 11.5 Gy. Results: 15 (65%) of the 23 tumors had been controlled. The actuarial local tumor control rate was 91% at 3 months, 73% at 6 months, and 44% at 12 months. At the time of analysis, 9 (82%) of the patients had died. The median survival time after the first GKS session was 17 months. The median survival time from the initial diagnosis was 65 months. No adverse radiation effect after GKS treatment occurred in any patient. Conclusions: GKS treatment might be an effective salvage treatment option for recurrent or residual supratentorial PNETs after multimodal treatment.

Salvage Radiosurgery for Recurrent Supratentorial Primitive Neuroectodermal Tumors: A Single Institutional Series and Review of the Literature

“…Also, the impact of dose and local control remains un clear. No correlation between dose and local control was noted by Se et al [16] (median margin dose, 11.5 Gy) or in our cases (median margin dose, 18 Gy). Further, dose evaluation was limited by the number of patients in this study and represents an area for further work in the fu ture.…”

“…This series had an extended interval from diagnosis to SRS (median 72.5 months), contributing to a prolonged median overall survival of 65 months and median survival after SRS of 17 months. Compared to the study of Se et al [16], our series had an older median age (22.5 vs. 17 years), which is has been shown to negatively impact prognosis [19]. Also, the impact of dose and local control remains un clear.…”

“…This group included 4 patients who survived at least 1 year after SRS with 2 patients surviving >7 years after SRS. There are <10 cases of reported longterm adult survivors with SPNET in the literature, and our cohort adds to the treatment strategies resulting in longterm survivors [16][17][18].…”

“…The first was pub lished in 2009 and describes 7 pediatric patients with PNETs, and however, 5 of the patients had tumor loca tion in the posterior fossa and 1 was pineal, which is both known to carry an improved prognosis and distinct ge netics [22]. The second cohort study was published in 2016 and describes 11 patients, half of them adult, with all tumors supratentorial in location [16]. This series had an extended interval from diagnosis to SRS (median 72.5 months), contributing to a prolonged median overall survival of 65 months and median survival after SRS of 17 months.…”