Feasibility study of delayed neurosurgical resection following pre-operative stereotactic radiosurgery for non-small cell lung cancer and melanoma brain metastases

This is a single arm study examining the feasibility of neurosurgical resection 7-21 days following completion of pre-operative stereotactic radiosurgery (SRS) for brain metastases (BMs), where clinically appropriate. This is in contrast to the current practice where there is no standardised time frame between SRS and neurosurgery. Translational blood and tumour tissue will also be obtained. 1. Stereotactic radiosurgery (SRS) SRS is a highly precise form of radiation therapy (RT) that delivers high doses of radiation in a few treatment fractions (typically 20-25Gy in 1-5 fractions) to individual BM tumours while sparing the surrounding normal brain tissue. For the patient this will involve first a planning CT scan as an outpatient, followed by 1-5 daily outpatient treatment visits to the Peter MacCallum Cancer Centre. Each treatment session will take approximately 30 minutes, depending on the number and size of lesions treated. This treatment is non-invasive and there will be no incision or general anaesthesia involved. 2. Neurosurgical resection of brain metastasis (BM) Following completion of SRS treatment, neurosurgical resection of the BM will be scheduled to take place 7-21 days later. This will be performed at the Royal Melbourne Hospital and will involve a few days of hospital stay after the surgery (usually 2-4 days). The patient will be under general anaesthesia during the procedure, which lasts approximately 4-6 hours. During the hospital stay patient's are monitored regularly by the neurosurgeon and hospital staff. 3. Collection of translational tissue Pre- and post-SRS bloods will be collected at 4 time points over 6 months, to coincide with routine follow-up appointments. The resected BM tissue will also be banked for research purposes. No additional resections or biopsies on top of standard of care treatments are necessary for this study. All specimens collected will be de-identified. After treatment: Trial participants will be reviewed as part of the study at 1 week, 4 weeks, 3 months and 6 months after completion of SRS. MRI scans of the brain be organised at 3 months post SRS. This follow-up schedule is standard for all patients having SRS and neurosurgery.