Leptomeningeal failure in patients with breast cancer receiving stereotactic radiosurgery for brain metastases.

PURPOSE: Prior studies suggest a high incidence of leptomeningeal failure (LMF) in breast cancer metastatic to brain. This study examines breast cancer-specific variables affecting development of LMF and survival after Gamma-Knife Radiosurgery (GKS).

METHODS

Between 2000-2010, 149 (breast) and 658 other-histology patients were treated with GKS. Hormone/HER2, age, local/distant brain failure, prior craniotomy, and prior whole-brain radiotherapy (WBRT) were assessed. Median follow-up was 54months (range, 0-106). Serial MRI determined local and distant-brain failure and LMF. Statistical analysis with categorical/continuous data comparisons were done with Fisher's-exact, Wilcoxon rank-sum, log-rank tests, and Cox-Proportional Hazard models.

RESULTS

Of 149 patients, 21 (14%) developed LMF (median time of 11.9months). None of the following predicted for LMF: Her2-status (HR=0.49, p=0.16), hormone-receptor status (HR=1.15, p=0.79), prior craniotomy (HR=1.58, p=0.42), prior WBRT (HR=1.36, p=0.55). Non-significant factors between patients that did (n=21) and did not (n=106) develop LMF included neurologic death (p=0.34) and median survival (8.6 vs 14.2months, respectively). Breast patients who had distant-failure after GKS (65/149; 43.6%) were more likely to later develop LMF (HR 4.2, p=0.005); including 15/65 (23%) patients who had distant-failure and developed LMF. Median time-to-death for patients experiencing LMF was 6.1months (IQR 3.4-7.8) from onset of LMF. Median survival from LMF to death was much longer in breast (6.1months) than in other (1.7months) histologies

CONCLUSION

Breast cancer patients had a longer survival after diagnosis of LMF versus other histologies. Neither ER/PR/HER2 status, nor prior surgery or prior WBRT predicted for development of LMF in breast patients.