A MULTIVARIATE-ANALYSIS OF PROGNOSTIC FACTORS IN MANAGEMENT OF PINEAL TUMOR

Purpose: A multivariate analysis of prognostic factors of treatment outcome of pineal tumor. Methods and Materials: From February 1979 to June 1987, 25 patients with primary pineal tumors were treated in our department. Patients were treated with either AECL Co-60 unit or 10 MV linear accelerator to the primary tumor with an adequate margin or to the whole brain (median dose of 36 Gy) with or without a cone-down boost of 10 to 20 Gy. Craniospinal irradiation was performed in two patients with positive CSF cytology. Minimum follow-up was 40 months. Patients were further stratified according to tumor type. Group I consisted of seven patients with pineal germinoma. Group II included nine patients with nongerminoma, and Group III represented nine patients treated without a histological verification but clinical diagnosis. Results: The relapse-free survival (RFS) of Group I patients was 100% and 86% at 2 and 5 years, respectively. Relapse-free survival was 55% and 21% at 2 and 5 years, respectively, for Group II patients. Six of 9 patients in Group II died of disease due to either local recurrence or tumor seeding. Eight of 9 patients in Group III remain no evidence of disease, and RFS was 89% at 2 and 5 years. Multivariate analysis revealed that tumor histology is the only significant prognosticator. Age, gender, type of surgical procedure, RT field, and tumor dose were not. Cox's regression model also failed to demonstrate a significant correlation of tumor seeding with the type of surgery. Conclusion: The type of tumors in the pineal region dictates the treatment outcome. Definitive radiation therapy is effective in controlling germinoma, whereas a more aggressive approach is needed to improve local control for nongerminoma. For a localized pineal lesion, we advocate that treatment can be tailored to the primary tumor with adequate margins. However, for locally advanced tumors whole brain or craniospinal irradiation should be considered. No definitive correlation between type of surgery and the probability of tumor seeding was identified.