Therapeutic modalities for pineal region tumors

Abstract

Since there is no radiographic test that can definitely predict the histology of a pineal tumor, we believe all patients should be treated first with a surgical approach to the tumor. This usually is accomplished by the supracerebellar-suboccipital route. Hydrocephalus is best treated at the time of surgery with ventricular drainage. Sometimes, surgery can decompress the CSF obstruction, and the need for a shunt can be averted following surgery; if not, the ventricular drain is converted to a shunt several days later. If a pineal tumor is found to be benign and encapsulated, it is removed by surgery, and the patient requires no additional therapy. Meningiomas, cysts, and low grade cystic astrocytomas all fall into this category. Some germ cell tumors are well differentiated and can also be grossly excised, but one must exercise caution in assuming that the entire tumor is benign. Many seemingly well-differentiated teratomas contain admixtures, sometimes microscopic, of more malignant elements. Careful pathological evaluation of the operative specimen and analysis of biological markers (AFP and beta-HCG) can alert the clinician to the presence of malignant tumor. With germinomas, radiation therapy is initially effective, and chemotherapy has a proven role in treating recurrences. Spinal radiotherapy is withheld unless there is a strong suspicion of spinal seeding. Tumors of pineal cell origin are radiosensitive and should be treated with radiation therapy. Because these tumors are rare, there is little data to date to justify one particular form of chemotherapy over another for recurrent pineal cell malignancies. Likewise, whether chemotherapy is preferable to radiation therapy in the initial treatment of nongerminomatous germ cell malignancies is as yet unclear.