Hesham Mohamed Hozayen, Hazem Mostafa Kamal, Mohamed Ali El-Gaidi, Ahmed Mohamed Alselisly

Abstract

Background: About 20% of all intracranial metastases occur in the posterior fossa, 25-50% is single, involving mainly cerebellum, and only small percentage (about 2%) of lesions concern brain stem, more rarely pineal region, or cerebellopontine angle. Metastasis in the posterior fossa is poorly tolerated because it can rapidly develop hydrocephalus, brain stem compression, upward transtentorial herniation, so it carries poorer prognosis than supratentorial metastasis, if left untreated. The best treatment options of single metastatic posterior fossa tumors are still debated, with the literature showing benefits of all three major treatment modalities—surgical resection, whole brain radiation (WBR), and stereotactic radiosurgery (SRS). Objectives: The aim of this work was to evaluate the outcome of the surgical resection of single metastatic posterior fossa tumors followed by further adjuvant treatment. Patients and methods: This was a prospective study including 20 patients of histopathology proven single posterior fossa metastasis fulfilling the prognostic criteria of surgery, which were: Karnofsky performance score ≥70, size of the metastatic mass (diameter of the mass ≥1 cm) and the primary tumor is controlled. Brain stem metastasis was excluded in addition to lymphoma or germ cell tumor (radio or chemosensitive). The patients underwent surgical excision and referred to the oncologists for further adjuvant treatment. Results: Out of the 20 patients included in the study, 14 were males and 6 females ranging from 41 to 72 years of age (average 57 years). There was no immediate postoperative mortality. Only 15% of cases had postoperative complications that did not require another surgery. 30% of cases were hydrocephalic, 5% of cases only required ventriculo-peritoneal shunts and the rest passed without shunting. 80% of our cases survived over 9 months with adjuvant therapy. Conclusion: Surgical excision of single metastatic posterior fossa tumor is a safe and beneficial procedure and helps avoid CSF diversion provided that specific prognostic criteria were adopted, which are Karnofsky performance score, extracranial metastasis, activity of the primary, histology of the primary and radiological features (size and location) of the lesion.