The Role of Postoperative Radiotherapy after Resection of Single Brain Metastases

Abstract

ABSTRACT To assess the value of whole brain radiotherapy (WBRT) after complete resection of a single brain metastasis we reviewed the records of 98 patients who had elective craniotomy between 1978 and 1985. Seventy-nine patients received postoperative WBRT (Group A) and 19 patients no radiotherapy (RT) (Group B). Neurological relapse was designated as local (i.e., at the site of the original metastasis) or distant (i.e., elsewhere in the brain). Postoperative WBRT significantly prolonged the time to any neurological relapse (P = 0.034) with a 1-year recurrence rate of 22% in Group A and 46% in Group B patients; however, it did not specifically control either local or distant cerebral recurrence. Recurrence of metastatic brain disease was not affected by location of the original lesion; however, meningeal relapse occurred in 38% of cerebellar lesions, but only in 4.7% of supratentorial metastases (P = 0.003). The total radiation dose or fractionation scheme of RT did not affect survival nor time to neurological relapse. The median survival was 20.6 and 14.4 months for Groups A and B, respectively (not statistically different). Forty-eight percent of Group A and 47% of Group B patients survived for 1 year or longer; however, 11% of patients who had received RT and survived 1 year developed severe radiation-induced dementia. All patients with radiation-related cerebral damage received hypo-fractionated RT with high daily fractions as commonly designed for rapid palliation of macroscopic brain metastases. Thus, postoperative WBRT may be an important adjunct to complete resection of a single brain metastasis, particularly in patients with limited or no systemic disease who have the potential for long-term survival or even cure, but it carries a substantial risk of late neurological toxicity when hypofractionated RT schedules are used. For these good-risk patients, postoperative WBRT should be administered by standard fractionation schemes of 180 to 200 cGy/day to a total of 4000 to 4500 cGy, or hyperfractionation, which provides even lower doses/fraction to minimize potential neurotoxicity while delivering a maximally efficacious total dose, should be considered.