COMPARATIVE RISK OF LEPTOMENINGEAL DISSEMINATION OF CANCER AFTER SURGERY OR STEREOTACTIC RADIOSURGERY FOR A SINGLE SUPRATENTORIAL SOLID TUMOR METASTASIS

OBJECTIVE: To test the hypothesis that differential risks of developing leptomeningeal disease (LMD) exist in patients having a single supratentorial brain metastasis resected via a piecemeal or en bloc approach or treated with stereotactic radiosurgery (SRS). METHODS: Between 1993 and 2006, 827 patients with a supratentorial brain metastasis underwent resection or SRS at The University of Texas M.D. Anderson Cancer Center. The primary outcome was the incidence of LMD. RESULTS: Resection was performed piecemeal in 191 patients and en bloc in 351 patients; 285 patients received SRS. LMD occurred in 33 patients, 29 in the resection group and 4 in the SRS group. Risk of LMD was significantly higher with piecemeal tumor resection than with other procedures (SRS: hazard ratio [HR] for piecemeal, 5.8; 95% confidence interval [CI], 1.9-17.2; P = 0.002; en bloc, HR for piecemeal, 2.7; 95% Cl, 1.3-5.6; P = 0.009). The difference between piecemeal and en bloc was particularly pronounced in patients with a melanoma primary (HR, 8.4; 95% Cl, 1.8-39.2; P = 0.007). The risk of LMD was not significantly different between en bloc resection and SRS (HR for en bloc, 2.1; 95% Cl, 0.7-6.4; P = 0.21). Similar results were obtained when comparing effects of SRS and both resection approaches after limiting the sample to patients with tumors in a specific volume range. CONCLUSION: Piecemeal resection of a supratentorial brain metastasis carries a higher risk of LMD than en bloc resection or SRS. Further assessment of the role of the 2 surgical resection approaches and SRS in a controlled prospective setting with large numbers of patients is warranted.