The potential for complete and durable response in nonglial primary brain tumors in children and young adults with enhanced chemotherapy delivery

PURPOSE Radiographic tumor response and survival were evaluated in the pediatric and young adult population with germ cell tumor, primary CNS lymphoma, or primitive neuroectodermal tumor receiving intra-arterial carboplatin-or methotrexate-based chemotherapy with osmotic blood-brain barrier disruption (BBBD). PATIENTS AND METHODS Thirty-four patients with histologically confirmed germ cell tumor (n = 9), primary CNS lymphoma (n = 9), or primitive neuroectodermal tumor (n = 16) were treated at the Oregon Health Sciences University from August 1981 through April 1995. Ages ranged from 1 to 30 years (mean, 18 years). Prior treatments included cranial radiation (n = 10) and chemotherapy (n = 18). All patients underwent extensive baseline neuropsychological evaluation and follow-up evaluation upon completion of the protocol, except for two patients who declined follow-up assessment. RESULTS Six hundred and forty-five BBBD procedures were performed with no mortality. Significant complications included one episode of tonsillar herniation with no neurologic sequelae, 4% incidence of seizures, and 3% incidence of sepsis or granulocytopenic fever. Ototoxicity was seen in 61% of patients who received carboplatin chemotherapy. Eighty-two percent of the patients had an objective response to treatment, including 62% with complete response and 20% with partial response. For most patients, cognitive functioning was maintained or improved at follow-up; this pattern was statistically significant. Three of the test scores for the seven patients who did not receive radiation therapy showed a cognitive decline of at least one standard deviation. Among the nine patients who received radiation therapy before or after BBBD chemotherapy, 11 test scores showed a decline in cognitive function at one standard deviation or more. DISCUSSION Durable responses were seen in patients with germ cell tumor and primary CNS lymphoma when treated with BBBD. Primitive neuroectodermal tumor requires post-chemotherapy radiotherapy for a durable response to be attained. Ototoxicity was a major form of toxicity in the patients who received carboplatin, but with the recent introduction of sodium thiosulfate, this problem has been markedly alleviated. Favorable cognitive outcomes appeared more likely for patients treated solely with BBBD chemotherapy and not with radiotherapy. Trends in the results for this sample are similar to those of previous research showing that radiotherapy is associated with cognitive decline. Current alternatives to enhanced drug delivery after BBBD include bone marrow transplantation; however, the increment in drug delivery is less, the number of courses is limited, and the morbidity and mortality are greater for bone marrow transplant than for BBBD. The current results suggest that in future trials, irradiation may not be needed in lymphoma and may not be necessary in some CNS germ cell tumors and that more focal radiotherapy should be further assessed in localized primitive neuroectodermal tumors.