Background: Non-small cell lung cancer is one of the leading causes of death in the developed countries. Patients die of local progression, disseminated disease or both. Brain metastases are often seen in non-small cell lung cancer patients and although they are frequently multiple, a subset of patients with a solitary brain metastasis (with controlled primary tumour) is regularly seen in clinical practice. Treatment of a solitary brain metastasis has usually been surgery, when possible, but the development of new stereotactic techniques of radiotherapy using a linear accelerator or the 'gamma knife' have provided new treatment options.

Objectives: To compare the effectiveness of surgery with that of radiosurgery, either combined with whole brain radiotherapy or administered alone, for patients with a solitary brain metastasis from successfully treated non-small cell lung cancer.

Search strategy: The following electronic databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL, 2004 issue 2), MEDLINE (1966 to present), EMBASE (1974 to present), CINAHL (1982 to present). Finally the Cochrane Lung Cancer Specialised Register was also searched.

Selection criteria: Randomised and controlled trials that compared surgery (with or without whole brain irradiation) with all types of radiosurgery (with or without whole brain irradiation) for solitary brain metastasis from non-small cell lung cancer. All other types of studies i.e.prospective or retrospective cohort studies were not considered appropriate.Studies including patients with multiple brain metastasis or diagnosed without the support of CT scan/MRI diagnostic imaging were also excluded.

Data collection and analysis: Two review authors independently screened the search results to identify suitable trials.

Main results: Despite extensive searching no randomised trials were found. Electronic search identified 686 references. A total of 47 were selected for further evaluation but none was relevant to this review.

Authors' conclusions: The reviewers felt that the inclusion of studies less rigorous than randomised trials would result in misleading findings. Cohort or single arm studies only provide partial information and have the risk of significant bias. From the evaluated studies, we found that a variety of different criteria were used for the definition of solitary brain metastasis. We observed that the term "single brain metastasis" was misused as synonymous with solitary brain metastasis. Some of the single arm or cohort studies come from single institutions where the availability of both techniques (radiosurgery and surgery) is not described. Therefore, a tendency to use the most accessible technique could be suspected. Finally, in order to determine which technique is superior for patients with a solitary brain metastasis from non-small cell lung cancer, an appropriate randomised trial should be designed. Based on the available evidence a meaningful conclusion cannot be drawn.