Stereotactic cranial radiosurgery for metastatic non-small-cell lung carcinoma

Abstract

Brain metastasis (BM) is either present at the initial presentation or emerges somewhere during the treatment course in up to 64 % patients. Therapeutic strategies of BM include chemotherapy, neurosurgery, whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or different combinations of them. In general, the priority of the single- or combination-treatment modality is usually decided in view of the information about the patient’s performance status, extracranial disease status, number, size, total volume, and localization of the BM. Based on the comparative phase III trials, with its high-precision capability in delivery of large doses of RT in a single session, SRS appears to be a noninvasive alternative to neurosurgery for single BM. Similarly, available data suggests almost equal effectiveness of SRS in ≤3 versus >3 BM situations. Therefore, in lack of any documented evidence suggesting inefficacy of SRS in patients with >3 BM, it is reasonable to offer SRS for suitable patients with larger BM. Tumor bed SRS (TB-SRS) is a relatively new treatment approach with no randomized data published to date. Available literature on use of TB-SRS is encouraging, but much is still unknown about the required doses and optimal margins, which underlines the need for appropriately designed future studies on this highly specific issue. Clinically, SRS alone results in better neurocognitive functions compared to WBRT and is equivalent to neurosurgery with no overall survival differences compared to these treatment options. Therefore, SRS alone can be safely utilized in particular patients with close follow-ups for distant brain recurrences. Technically, SRS can be performed in various ways by using Gamma Knife or high-capacity novel linear accelerators. Absolutely some technical differences exist among diverse SRS hardware and related treatment planning systems with associated pros and cons, but available comparative outcomes do not suggest any differences in clinical outcomes including the tumor control and survival rates, as long as the fundamental tenets of SRS are pursued.