Brain metastasis treated with Cyberknife.

Background: Cyberknife 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.

Methods: We 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.

Results: After 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.

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