BACKGROUNDCyberknife can greatly raise the fractional dose of stereotactic radiosurgery, thus improving its clinical efficacy. We retrospectively analyzed clinical outcomes of brain metastasis treated with Cyberknife.

METHODSWe analyzed 40 cases of brain metastases treated with Cyberknife in the Tianjin Cancer Hospital from August 1, 2006 to August 1, 2007, for a total of 68 lesions with maximal diameter of 0.4 - 7.5 cm (average 1.88 cm). Total hypofractional radiated dosage was 18 - 36 Gy (5 - 25 Gy/F, 1 - 5 F) by Cyberknife. We evaluated the remission rate of clinical symptoms, correlation factors to new foci, 3-month local control rates, and 3-month and 1-year survival rates. All patients were followed up for more than 14 months.

RESULTSAfter 1 week, clinical remission was 90.0% (36/40). After 3 months, the local control rate and therapeutic effective rate were 77.9% (53/68) and 94.1% (64/68), respectively, as observed by cranium augmentation CT or MRI. The three-month, six-month and 1-year survival rates were 97.5% (39/40), 82.5% (33/40) and 67.5% (27/40), respectively. Fourteen patients had neopathy outside the original lesion after 3 months. Neopathy was not correlated with age, whole-brain radiotherapy, number of original lesions, maximum diameter of the original lesion, therapeutic dose per fraction, therapeutic frequency or total therapeutic dose.

CONCLUSIONSCyberknife got perfect clinical outcomes by higher dosage per fraction. It is an appropriate and valid treatment shortcut for brain metastasis.