Repeat stereotactic radiosurgery in the management of brain metastases from non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is characterized by brain metastases that occur in about 30 to 50% of patients. To control tumor growth potential with maintaining neurocognitive function is important in the recent radiotherapy against brain metastases. From this viewpoint, we investigated the utility of repeat stereotactic radiosurgery (SRS) with a linear accelerator in the management of brain metastases from NSCLC. Between October 1998 and May 2010, 28 patients harboring brain metastases received repeat SRS (20 men and 8 women, with the age ranged from 51 to 79). The total number of SRS sessions ranged from 2 to 5, and the total number of lesions in one patient ranged from 1 to 8. Neurological decline due to uncontrolled brain lesions was identified in 9 of 28 patients after the repeat SRS, while the remaining 19 patients showed no neurological decline. Out of the 28 patients, 18 patients died by July 1, 2010; 12 patients died of active extracranial disease and 6 patients died from progressive brain lesions, considered neurological death. The 2-year and 4-year overall survival rates were 51% and 23%, respectively, and the median survival time was 26 months. In conclusion, repeat SRS is a preferred option to manage brain metastases from NSCLC, leading to a long survival with a decreased neurological decline. Repeat SRS is promising to preserve neurocognition, because the convergent dose distribution decreases the unfavorable influences from radiation on germinal niches, thereby preserving neural stem cells that are responsible for the nervous system repair.