Surgery and radiotherapy compared with gamma knife radiosurgery in the treatment of solitary cerebral metastases of small diameter

Object. The aim of this retrospective study was to compare treatment result s of surgery plus whole-brain radiation therapy (WBRT) with gamma knife rad iosurgery alone as the primary treatment for solitary cerebral metastases s uitable for radiosurgical treatment. Methods. Patients who had a single circumscribed tumor that was 3.5 cm or s maller in diameter were included. Treatment results were compared between m icrosurgery plus WBRT (52 patients, median tumor dose 50 Gy) and radiosurge ry alone (56 patients, median prescribed tumor dose 22 Gy). In case of loca l/distant tumor recurrence in the radiosurgery group, additional radiosurgi cal treatment was administered in patients with stable systemic disease. Su rvival time was analyzed using the Kaplan-Meier method, and prognostic fact ors were obtained from the Cox model. The patient groups did not differ in terms of age, gender, pretreatment Karnofsky Performance Scale (KPS) score, duration of symptoms, tumor location, histological findings, status of the primary tumor, time to metastasis, and cause of death. Patients who suffer ed from larger lesions underwent surgery (p < 0.01). The 1-year survival ra te (median survival) was 53% (68 weeks) in the surgical group and 43% (35 w eeks) in the radiosurgical group (p = 0.19). The 1-year local tumor control rates after surgery and radiosurgery were 75% and 83%, respectively (p = 0 .49), and the 1-year neurological death rates in these groups were 37% and 39% (p = 0.8). Shorter overall survival time in the radiosurgery group was related to higher systemic death rates. A pretreatment KPS score of less th an 70 was a predictor of unfavorable survival. Perioperative morbidity and mortality fates were 7.7% and 1.6% in the resection group, and 8.9 and 1.2% in the radiosurgery group, respectively. Four patients presented with tran sient radiogenic complications after radiosurgery. Conclusions. Radiosurgery alone can result in local tumor control rates as good as those for surgery plus WBRT in selected patients. Radiosurgery shou ld not be routinely combined with radiotherapy.