Postoperative treatment of patients with anaplastic oligodendrogliomas. Thirty years' experience of the Maria Sklodowska-Curie Memorial Centre in Kraków, 1975–2000

Abstract

Background

Anaplastic oligodendrogliomas (AO) are infiltrative, mostly supratentorial tumours, often bilaterally affecting the white matter. Radiotherapy alone or in combination with chemotherapy have a role in the adjuvant treatment of AO, but currently the efficacy of various treatment modalities could not be definitively determined because of the heterogeneity of the therapies used.

Aim

Assessment of the efficacy of altered therapy schedules in postoperative treatment of patients with anaplastic oligodendrogliomas

Materials/Methods

Between 1975 and 2000, 101 adult patients with anaplastic oligodendrogliomas were postoperatively treated in our institution. During this period patients received conventional radiation therapy and chemotherapy (CRT/CH), conventional radiation therapy (CRT), and split course hypofractionated radiation therapy (SCHRT).

Between 1975 and 1985, CRT/CH was applied in 42 patients. Whole brain irradiation was delivered; the tumour dose of 5Gy in 25 fractions over 5 weeks was calculated at the midplane of the skull. Then treatment fields were reduced and a 10Gy boost was given in 5 fractions over 5 days to the known tumour bearing area. On the last day of irradiation patients began the first of six planned series of chemotherapy with CCNU, given 100mg/², orally every 8 weeks. From 1986 to 1990, CRT was received by 27 patients. Irradiation was only as described above. Between 1991 and 2000, 32 patients were given SCHRT. There were 3 courses of irradiation separated by a one-month interval. In each of the two first series patients received 20Gy in 5 fractions in five days to the whole brain, and in the third course a 20Gy boost in 5 fractions over 5 days was given as in the CRT regimen.

Results

Actuarial overall survival rates at two and five years were 38% and 10% respectively for patients treated with CRT/CH, 36% and 11% for the CRT group, and 23% and 6% for the SCHRT option. Multivariate analysis revealed that only age was a significant factor. Patients aged 45 years or less carried the best prognosis.

Conclusions

The efficacy of different postoperative treatments administered to our patients with anaplastic oligodendrogliomas gave approximately comparable and unrewarding poor results.