Outcome comparison of patients who develop leptomeningeal disease or distant brain recurrence after brain metastases resection cavity radiosurgery

BACKGROUND: To compare the outcomes between patients with leptomeningeal disease (LMD) and distant brain recurrence (DBR) after stereotactic radiosurgery (SRS) brain metastases (BM) resection cavity. METHODS: Twenty-nine patients having single-fraction SRS after BM resection who developed either LMD (n = 11) or DBR (n = 18) as their initial and only site of intracranial progression were retrospectively reviewed. RESULTS: Patients developing LMD more commonly had a metachronous presentation (91% vs 50%, P = .04) and recursive partitioning class 1 status (45% vs 6%, P = .02). There was no difference in the median time from SRS to the development of LMD or DBR (5.0 vs 3.8 months, P = .68). The majority of patients with LMD (10/11, 91%) developed the nodular variant (nLMD). Treatment for LMD was repeat SRS (n = 4), whole-brain radiation therapy (WBRT; n = 5), resection + WBRT (n = 1), and no treatment (n = 1). Treatment for DBR was repeat SRS (n = 9), WBRT (n = 3), resection + resection cavity SRS (n = 1), and no treatment (n = 5). Median overall survival (OS) from time of resection cavity SRS was 15.7 months in the LMD group and 12.7 months in the DBR group (P = .60), respectively. Median OS in salvage SRS and salvage WBRT were 25.4 and 5.0 months in the nLMD group (P = .004) while 18.7 and 16.2 months in the DBR group (P = .30), respectively. CONCLUSIONS: Following BM resection cavity SRS, nLMD recurrence is much more frequent than classical LMD. Salvage SRS may be considered for selected patients with nLMD, reserving salvage WBRT for patients with extensive intracranial disease without compromising survival. Further study with larger numbers of patients is needed.