Outcome variation among "radioresistant" brain metastases treated with stereotactic radiosurgery

To determine the influence of histopathological diagnosis on the outcome of "radioresistant" brain metastases treated with stereotactic radiosurgery (SRS).

Patients (n = 189) with "radioresistant" brain metastases (n = 264) were consecutively treated with SRS between August 1991 and July 2002. The primary site of brain metastases was melanoma (n = 103), renal cell carcinoma (n = 77), and sarcoma (n = 9). The median age of the patients was 52 years, and the median Karnofsky Performance Scale score was 80. Initial brain metastasis presentation was single in 112 patients (59%). The median SRS dose was 18 Gy (range, 10-24 Gy). The median tumor volume was 1.6 cm3 (range, 0.06-27.5 cm3). The median follow-up of all patients was 7.4 months (range, 0.16-52 mo).

The actuarial freedom from progression after 1 year was 64% for renal cell carcinoma patients, 47% for melanoma patients, and 0% for sarcoma patients (P < 0.001). The median survival time for all patients from time of SRS was 7.5 months. The rate of 1-year survival was 40% for renal cell carcinoma patients, 25% for melanoma patients, and 22% for sarcoma patients (P = 0.0354). The incidence of neurological death was lower among patients diagnosed with renal cell carcinoma (31%) than among patients with melanoma (66%) or sarcoma (60%) (P = 0.001).

Survival after SRS is significantly worse for patients with melanoma and sarcoma brain metastases compared with patients with renal cell carcinoma. Our data show that progressive brain metastases seem to cause most of the cancer-related deaths among patients with SRS-treated melanoma and sarcoma brain metastases. Future investigations using chemotherapy or novel agents to enhance the effectiveness of SRS to melanoma and sarcoma brain metastases seem warranted.