Metastasis to the Posterior Fossa

Posterior fossa metastasis represents a common and challenging clinical situation for the neurosurgical oncologist and interdisciplinary neuro-oncological teams. More than 30% of cancer patients develop brain metastasis, with the incidence increasing as systemic therapies offer longer survival for many cancer patients. Furthermore, as brain imaging techniques improve and become more widely available, solitary and multiple metastases are being discovered more frequently. Patients with posterior fossa metastasis may be asymptomatic or may present with focal or diffuse neurological deficits from space-occupying lesions compressing the brainstem or cranial nerves. The treating physician must take into account the patient’s disease state and the location and number of metastases to plan surgical, radiosurgical, or fractionated radiotherapeutic intervention. Comprehensive anatomical knowledge of the posterior fossa is crucial. En bloc, gross total resection of the tumor along with its gliotic pseudocapsule is the favored technique when possible. Since the 1920s, radiation therapy has helped patients with significant neurological dysfunction due to metastatic cancer. More recently, stereotactic radiosurgery has found favor as upfront treatment or as an adjuvant after surgical excision. Whole-brain radiation therapy can also be considered when SRS may be less effective because of higher numbers of metastases. Thus, treatment of patients with intracranial metastasis is optimized with an evidence-based approach combined with knowledge of the cerebellar and posterior fossa anatomies and surgical techniques.