Stage Information for CNS Germ Cell Tumors
There is no universally accepted staging system for germ cell tumors (GCTs), but a modified Chang Staging System has been traditionally used. Staging evaluation of CNS GCTs includes the following:
- Magnetic resonance imaging (MRI). In addition to whole-brain MRI, MRI of the spine is required.
- Lumbar cerebrospinal fluid (CSF). When medically permissible, lumbar CSF should be obtained for the measurement of tumor markers (alpha-fetoprotein [AFP] and beta subunit human chorionic gonadotropin [beta-HCG]) and for cytopathologic review.
Serum tumor markers are often obtained for AFP and beta-HCG; however, they do not serve as a substitute for CSF tumor markers.
Patients with localized disease and negative CSF cytology are considered to be M0 (no metastasis); patients with positive CSF cytology or patients with drop metastasis in the spine or cranial subarachnoid space are considered to be M+ (metastatic-positive). Appropriate staging is crucial since patients with metastatic disease may receive higher total doses and more extended radiation fields.
Staging of patients with bifocal intracranial germinomas limited to the suprasellar and pineal region remains controversial, with some classifying these tumors as localized disease and others classifying such presentations as disseminated disease.
GCTs can disseminate throughout the neuraxis at diagnosis or at any disease stage. Several unusual patterns of spread may occur in germinomas, such as subependymal dissemination in the lateral or third ventricles and parenchymal infiltration. Rarely, extracranial spread to lung and bone has also been reported.[3,4]References
- Fujimaki T, Mishima K, Asai A, et al.: Levels of beta-human chorionic gonadotropin in cerebrospinal fluid of patients with malignant germ cell tumor can be used to detect early recurrence and monitor the response to treatment. Jpn J Clin Oncol 30 (7): 291-4, 2000. [PUBMED Abstract]
- Weksberg DC, Shibamoto Y, Paulino AC: Bifocal intracranial germinoma: a retrospective analysis of treatment outcomes in 20 patients and review of the literature. Int J Radiat Oncol Biol Phys 82 (4): 1341-51, 2012. [PUBMED Abstract]
- Jennings MT, Gelman R, Hochberg F: Intracranial germ-cell tumors: natural history and pathogenesis. J Neurosurg 63 (2): 155-67, 1985. [PUBMED Abstract]
- Gay JC, Janco RL, Lukens JN: Systemic metastases in primary intracranial germinoma. Case report and literature review. Cancer 55 (11): 2688-90, 1985. [PUBMED Abstract]