Phase II Trial of Response-Based Radiation Therapy for Patients with Localized Germinoma: A Children's Oncology Group Study.

Overview

abstract

BACKGROUND: The study aimed to evaluate whether simplified chemotherapy followed by dose-reduced irradiation was effective for treating patients (ages 3-21 years) with localized germinoma. The primary endpoint was 3-year progression free survival (PFS) rate. METHODS: Patients with a complete response to chemotherapy with carboplatin and etoposide received 18Gy WVI +12Gy boost to the tumor bed. Patients with partial response proceeded to 24Gy WVI + 12Gy. Longitudinal cognitive functioning was evaluated prospectively on ALTE07C1 and was a primary study aim. RESULTS: 151 patients were enrolled; 137 were eligible. Among 90 evaluable patients, 74 were treated with 18Gy and 16 with 24Gy WVI. The study failed to demonstrate non-inferiority of the 18Gy WVI regimen compared to the design threshold of 95% 3-year PFS rate, where, per design, patients who could not be assessed for progression at 3 years were counted as failures. The KM-based 3-year PFS estimates were 94.5 ±2.7% and 93.75 ± 6.1% for the 18Gy and 24Gy WVI cohorts, respectively. Collectively, estimated mean IQ and attention/concentration were within normal range. A lower mean attention score was observed at 9 months for patients treated with 24Gy. Acute effects in processing speed were observed in the 18Gy cohort at 9 months which improved at 30-month assessment. CONCLUSIONS: While a failure according to the prospective statistical noninferiority design, this study demonstrated high rates of chemotherapy responses, favorable KM based PFS and OS estimates in the context of reduced irradiation doses and holds promise for lower long-term morbidities for patients with germinoma.