Radiation therapy for histologically confirmed primary central nervous system germinoma.

PURPOSE

To evaluate survival and patterns of recurrence in patients with primary central nervous system germinoma treated with radiation therapy.

METHODS AND MATERIALS

Data regarding 48 patients with histologically confirmed, primary central nervous system germinoma were reviewed. All had been operated on at the Mayo Clinic between the years 1935 and 1993. Thirty-two patients (67%) were treated since 1973. The study group included 39 males and 9 females, with a median age at diagnosis of 17 years (range, 6-42 years). Twelve patients (25%) were treated with craniospinal axis irradiation, 11 (23%) received whole-brain irradiation without spinal axis irradiation, and 24 (50%) underwent partial-brain irradiation. Treatment volumes were unknown in one patient. The median dose to the primary tumor was 44.00 Gy (range, 7.44-59.40 Gy). The median follow-up was 5.5 years (range, 4 months to 37 years).

RESULTS

Actuarial 5-year and 10-year survival for the entire study group of patients was 80%. There was a trend toward improved survival in patients treated after 1973 (introduction of computed tomography) with 5-year and 10-year survival of 91% vs. 63% in prior years (p = 0.07). For the group of 31 patients treated since 1973 with known treatment volumes, the spinal axis failure rate at 5 years was 49% for patients treated with partial brain fields (11 patients) vs. 0% for those having undergone whole brain (10 patients) or craniospinal axis (10 patients) irradiation (p = 0.007). The rate of brain failure was also significantly higher in patients receiving less than whole-brain irradiation; at 5 years, 45% of the patients treated with partial-brain fields had intracranial recurrence of disease compared to 6 % of patients treated with craniospinal axis or whole-brain irradiation (p = 0.01). Among the 32 modern era patients, the rate of brain failure was higher in patients who received doses less than 40 Gy (median dose, 48.55 Gy; range, 30.60-59.40 Gy) to the primary tumor (5-year brain failure rate 52% vs. 11%, p = 0.002).

CONCLUSION

The long-term survival of patients with histologically proven CNS germinoma treated with radiation is excellent. Whole-brain or craniospinal axis irradiation appears to result in fewer spine and brain failures than does partial-brain irradiation. Furthermore, the administration of doses greater than 40 Gy to the primary tumor is associated with better local control.