Clinical Outcomes of Gamma Knife Radiosurgery for Metastatic Brain Tumors from Gynecologic Cancer : Prognostic Factors in Local Treatment Failure and Survival

Abstract

Objective: Brain metastases in gynecologic cancer (ovarian, endometrial, and cervical cancer) patients are rare, and the efficacy of Gamma Knife Radiosurgery (GKRS) to treat these had not been evaluated. We assessed the efficacy of GKRS and prognostic factors for tumor control and survival in brain metastasis from gynecologic cancers.

Methods: This retrospective study was approved by the institutional review board. From May 1995 to October 2012, 26 women (mean age 51.3 years, range 27-70 years) with metastatic brain tumors from gynecologic cancer were treated with GKRS. We reviewed their outcomes, radiological responses, and clinical status.

Results: In total 24 patients (59 lesions) were available for follow-up imaging. The median follow-up time was 9 months. The mean treated tumor volume at the time of GKRS was 8185 mm(3) (range 10-19500 mm(3)), and the median dose delivered to the tumor margin was 25 Gy (range, 10-30 Gy). A local tumor control rate was 89.8% (53 of 59 tumors). The median overall survival was 9.5 months after GKRS (range, 1-102 months). Age-associated multivariate analysis indicated that the Karnofsky performance status (KPS), the recursive partitioning analysis (RPA) classification, and the number of treated lesions were significant prognostic factors for overall survival (HR=0.162, p=0.008, HR=0.107, p=0.038, and HR=2.897, p=0.045, respectively).

Conclusion: GKRS is safe and effective for the management of brain metastasis from gynecologic cancers. The clinical status of the patient is important in determining the overall survival time.

Keywords: Brain metastases; Gamma Knife Radiosurgery; Gynecologic cancer; Prognostic factor; Survival.

Fig. 1. Kaplan-Meier curve of overall survival outcomes after GKRS. The median survival time after GKRS was 9.5 months. The survival rates were 82.1%, 34.7%, 13.0%, and 6.9% at 1, 6, 12, and 24 months after GKRS, respectively.

Fig. 2. Kaplan-Meier curve of overall survival after treatment of ovarian, endometrial and cervical cancer brain metastasis with GKRS. Patients with ovarian cancer had a median survival of 12 months. Patients with endometrial cancer had a median survival of 7.5 months, and patients with cervical cancer had a median survival of 3.5 months. There was no statistical significance between the groups (ovarian cancer vs. endometrial cancer, p=0.801, endometrial cancer vs. cervical cancer, p=0.387, cervical cancer vs. ovarian cancer, p=0.129).

Fig. 3. A : Age-associated multivariate analysis indicated that the KPS score (≥80) was a significant prognostic factor for overall survival (HR=0.162, p=0.008). B : RPA Kaplan-Meier survival curve showed significant difference between the three classes (Class 2, HR=0.508, p=0.178, Class 1, HR=0.107, p=0.038). C : Age-associated multivariate analysis showed that the number of treated lesions (<4) was a significant prognostic factor for overall survival (HR=2.897, p=0.045).