A phase II trial of preirradiation carboplatin in newly diagnosed germinoma of the central nervous system.

BACKGROUND: Central nervous system (CNS) germinomas respond readily to both radiotherapy and chemotherapy. This study was designed to selectively reduce the dose of radiotherapy in those patients expressing a complete response (CR) to neoadjuvant carboplatin.
METHODS: A Phase II trial with carboplatin was conducted in 11 newly diagnosed patients with histologically confirmed, radiologically evaluable CNS germinomas before they received radiotherapy. All patients had normal cerebrospinal fluid and serum tumor markers (i.e., human chorionic gonadotropin [HCG] and alpha fetoprotein [AFP]). Seven patients had localized tumors (three pineal, three suprasellar, and one thalamus), and four had multifocal disease. Their median age at diagnosis was 13 years (range, 7-31). One course of carboplatin consisted of 150 mg/m2 weekly for 4 consecutive weeks followed by a 2-week break. Response was evaluated after two courses. If a patient had a CR to chemotherapy, the radiotherapy doses to the involved field and the craniospinal axis were lowered from 50 Gy to 30 Gy and from 36 Gy to 21 Gy, respectively. If less than a CR was observed, two additional courses of chemotherapy were administered, after which the patient's response was reevaluated. Less than a CR required full radiotherapy doses. The radiotherapy volume was determined by the extent of disease at diagnosis (i.e., localized disease was treated with an involved field and craniospinal therapy was used for disseminated disease).
RESULTS: Seven patients had a CR to carboplatin (five patients after two courses and two patients after four courses). Three patients had a partial response (one after four courses and two after two courses). The investigators of the latter two patients chose not to give additional chemotherapy. Another patient opted for radiotherapy after receiving only one course of chemotherapy and was not evaluable for response. Ten of 11 patients remain in continuous remission for a median of 25 months. One patient had a recurrence. He presented with a localized pineal germinoma and had a CR after two courses of carboplatin. He received 30 Gy of involved field radiotherapy and suffered a relapse 5 months later in multiple CNS sites. He died 23 months after diagnosis with diffuse CNS and peritoneal metastases. His serum AFP and HCG levels were elevated, consistent with a nongerminoma germ cell tumor.
CONCLUSIONS: Carboplatin was highly active in treating newly diagnosed CNS germinomas. Further chemotherapy studies eventually may permit additional dose reductions and/or elimination of radiotherapy for patients with CNS germinomas.