Stereotactic Radiosurgery For Patients With Brain Metastases From Small Cell Lung Cancer

Rodney Wegner1, Adam Olson1, Douglas Kondziolka, MSc, MD2, Ajay Niranjan, MCh2, Dade Lunsford1, John C. Flickinger, MD3

1UPMC, Pittsburgh, PA, USA 2Department of Neurological Surgery, University of Pittsburgh 3Department of Radiation Oncology, University of Pittsburgh

Keywords: gamma knife, radiosurgery, lung cancer, brain metastasis, outcome

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Abstract

     Patients with small cell lung cancer have a high likelihood of developing brain metastases with 50% of patients having intracranial spread at 2 years. Many of these patients will have prophylactic cranial irradiation (PCI) or eventually undergo whole brain radiation therapy (WBRT). Despite these treatments, a large number of these patients will have progression of their intracranial disease and require additional local therapy.
     Stereotactic radiosurgery (SRS) is an important treatment option for such patients and our goal was to define outcomes.
     We retrospectively reviewed the charts of 44 patients with brain metastases from small cell lung cancer treated with gamma knife SRS between July 1991 and June 2008. 
     Multivariate analysis was utilized to determine significant prognostic factors influencing survival.
     The median follow-up from SRS in this patient population was 9 months (1-49 months). The median overall survival (OS) was 9 months after SRS. Karnofsky performance status (KPS) and combined treatment involving WBRT and SRS within four weeks were the two factors identified as being significant predictors of increased overall survival (p=0.033 and 0.040, respectively). Patients treated with a combined approach had a median OS of 14 months compared to 6 months if SRS was delivered alone. The following factors did not significantly impact outcome: age, active systemic disease, total tumor volume, tumor volume =7cm3, time to development of brain metastases, having a solitary metastasis, having 4 or more brain metastases, or having 7 or more metastases. Only 1 patient (2.2%) had symptomatic intracranial swelling related to treatment which responded to a short course of steroids. An 87% response rate was confirmed in the 70% of patients that had imaging assessable after SRS. New brain metastases outside of the treated area developed in 61% of patients at a median time of 7 months; 81% of these patients had received previous WBRT. 
     This was a retrospective study.
     Stereotactic radiosurgery for small cell lung carcinoma metastases provided safe and effective local tumor control in the majority of patients.  
     For patients who have not received previous WBRT, have a good KPS, and have a limited number of metastatic lesions, consideration should be given to a combined approach of SRS and WBRT.


Acknowledgements

Project Roles:

R. Wegner (), A. Olson (), D. Kondziolka (), A. Niranjan (), D. Lunsford (), J. Flickinger ()