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    Treatment

Since pineal region tumors are among the most dangerous intracranial masses to excise, there has been an ongoing debate for at least the last half-century concerning their surgical management. The debate centers on whether it is in the patient's best interest to explore these lesions at the time of their diagnosis, or whether the obstructive hydrocephalus should be treated with a shunt and the posterior third ventricular tumor irradiated without a tissue diagnosis-maneuvers which can be carried out with a low morbidity and mortality rate.

Even though it has been demonstrated repeatedly that it is feasible for highly experienced surgeons to operate on lesions in the posterior third ventricle with a combined morbidity and mortality rate of under 10 percent, whether all patients with a pineal region tumor require surgical intervention remains a matter of judgment. For example, patients in whom cytologic examination of the cerebrospinal fluid shows malignant cells, patients with evidence of either spinal or extraneural metastases, and patients harboring synchronous anterior and posterior third ventricular tumors and in whom a tumor marker is elevated, most likely have a germinoma or other malignant germ cell tumor and may not require direct intervention.

In contrast to these cases, there is a group of patients in whom surgical exploration is mandatory. These are patients previously treated with a shunt and radiation therapy without a tissue diagnosis who present with progressive neurological problems in the presence of a functioning shunt. Such patients have often survived for a period of years, and benign or relatively benign tumors are particularly frequent among this select group. The controversy centers on the posterior third ventricular lesion whose nature cannot be established preoperatively in spite of the best available diagnostic modalities. In centers in Japan and in England these patients are managed on a protocol of local field irradiation followed by assessment by MRI as to whether tumor regression occurs. If this does occur, the patients are subjected to whole-brain or whole-CNS irradiation. Among two groups of patients treated in Tokyo between 1975 and 1988 there was a 73 percent 5-year survival of those with histologically diagnosed germinomas and an 83 percent 5-year survival of those with suspected germinomas, outcomes which the investigators reported to be statistically the same. Patients not responsive to the 20 Gy local field irradiation are approached surgically. Among patients with this group of nongerminomatous tumors, the 5-year survival rate was 28 percent. Hoffman et al. have reported a 45 percent survival among patients with non-germ cell tumors treated with surgery and radiation.

In the reported experience from the Royal Marsden Hospital. 50 patients with pineal tumors were managed with an initial 20 Gy local field irradiation. Responders were then given another 30 Gy to the brain and to the spine. These authors reported an 81 percent 5-year survival rate among patients with histologically diagnosed germinomas who respond to 20 Gy irradiation, 64 percent 5-year survival among those with non-germ cell tumors, and 18 percent 5-year survival among those with malignant teratomas.

The malignant teratomas have a particularly bad prognosis and are those tumors which often present with elevations in the tumor markers and which recur rapidly following irradiation or surgical excision. It is particularly in these tumors and in patients with tumor recurrence that chemotherapeutic approaches seem to have a particular value. Currently cisplatin-based therapy of VP-16 and cisplatin alternating with vincristine, methotrexate, and bleomycin have been used to treat these cases with encouraging results.

  
 
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