Radiation therapy with or without surgery in the management of low-grade brain astrocytomas. A retrospective study of 120 patients

From 1977 to 1988, 120 consecutive patients with a diagnosis of low-grade astrocytoma were referred to our department for radiotherapy. Forty-one patients (group 1) underwent surgery and post operative external radiation therapy (2 gross total resections and 39 subtotal resections). Sixty-nine patients underwent exclusive external radiotherapy (group 2). In ten patients, the irradiation was delivered by stereotactic implantation of iridium-192 wires into the tumor with or without external irradiation (group 3). Ten had pilocystic astrocytomas (mean age, 24 years) and twenty had microcystic astrocytomas (mean age, 35.4 years). The 5- and 10-year survival rates were 55.6% and 44.4%, respectively and 55% and 48%. Ninety astrocytomas were classified as ordinary astrocytoma (mean age, 36.8 years). The 5- and 10-year overall survival rates were 51% and 20.5%, respectively. The same probabilities at 5 and 10 years were 65% and 37% respectively, for group 1, 38.8% and 12.7% for group 2 and, 78.8 and 22.5% for group 3. In multivariate analysis, two prognostic factors had a significant impact on overall survival: IK score (IK < 90 vs IK ≥ 90, p = 0.0001), surgical resection (surgical resection and post operative radiotherapy vs radiation therapy alone, p = 0.012). However, the patients who underwent surgical resection were those in the best condition, having tumors that were easily accessible and less invasive. (Author), 34 refs., 3 tabs., 1 fig