Purpose: There is no consensus on the treatment strategy for adult patients with cerebral low-grade glioma. The diagnosis and primary treatment are usually undertaken by surgery. Some investigators doubt the efficacy of postoperative radiotherapy (RT), whereas others advise routine postoperative RT. We report the primary results of a multicenter randomized trial on this controversy.
Methods and materials: From 24 European centers, 311 adult patients with low-grade glioma were randomized centrally after surgery from March 1986 through September 1997, between the two arms of the trial. The irradiated group received 54 Gy in 6 weeks. The other patients did not receive any treatment after surgery until the tumor showed progression, defined as clinical-neurologic deterioration and evidence of progressive tumor on imaging.
Results: Of 290 eligible and assessable patients (93%), the irradiated group showed a significant (log-rank p = 0.02) improvement in time to progression but not in overall survival, with a median follow-up of 5 years. The 5-year estimate was, respectively, 63% vs. 66% (overall survival) and 44% vs. 37% (time to progression) for the treated and control arms. Different treatment modalities, including RT, were undertaken for the 85 controls when a progressive tumor was noted.
Conclusion: Early postoperative conventional RT such as that used for this protocol appears to improve the time to progression or progression-free survival, but not overall survival, for patients with low-grade glioma.