Stereotactic radiosurgery for brain metastases in small cell lung cancer: The Davidoff Cancer Center experience

Background: Prophylactic cranial irradiation (PCI) omission in favor of brain magnetic resonance imaging (MRI) staging and surveillance in the management of small cell lung cancer (SCLC) is controversial yet accepted by some centers. The use of MRI suggests performing stereotactic radiosurgery (SRS) treatment for limited brain metastases. Data regarding SRS efficacy in this setting is limited. Objectives: To assess intracranial objective response rate (iORR), progression-free survival (iPFS), intracranial failure patterns, overall survival (OS) and time-to-whole-brain radiation therapy (WBRT)/death, whichever occurred first (TTWD) with SRS in SCLC. Methods: The study comprised 10 consecutive SCLC patients with brain metastases treated with SRS and followed-up at Davidoff Cancer center between Aug 2012 and March 2019. Brain MRI images were reviewed by a neuro-radiology specialist. Results: iORR was 57% as assessed by response assessment in neuro-oncology brain metastases. Intracranial progression developed in 8 patients. Median iPFS was 4.0 months (95% confidence interval [95%CI] 1.7-7.2). In-site, off-site and combined pattern of intracranial failure was seen in 0,5, and 3 patients, respectively; median number of new brain lesions following SRS was 4 (range, 1-12). SRS was performed 10 additional times in 6 patients (median number of lesions irradiated per round was 1, range 1-5). WBRT was administered in 3 patients. Median TTWD was 20.9 months (95% CI, 1.9-26.8). Median OS since SRS administration was 23.2 months (95% CI, 4.2-not reached). Conclusions: MRI surveillance with multiple rounds of SRS may serve a reasonable alternative to PCI or therapeutic WBRT in SCLC.