Evaluating treatment outcomes of fractionated stereotactic radiotherapy in patients with small and moderate-sized brain metastases.

This study investigated the effectiveness and safety of fractionated stereotactic radiation therapy (FSRT) for patients with small and moderate-sized brain metastases (BM). The data showed that FSRT was safe and effective in patients with BM of any size with excellent local control.

Stereotactic radiosurgery (SRS) is commonly used in patients with BM. SRS can directly target the tumor only in the brain, rather than targeting the whole brain. SRS uses high-energy radiation to kill cancer cells by damaging their DNA. SRS is delivered in a single fraction and is useful for small intact BM.

FSRT is an option for treating larger BM (greater than 2 cm). FSRT uses higher doses of radiation in a shorter period of time and targets a specific area from different angles. However, whether FSRT is an effective and safe option for small and moderate-sized BM is still unknown.

This study involved 60 patients with 133 BM from lung cancer or melanoma. Patients were treated with FSRT. Patients were given an average total dose of 18-32.5 Gy in 3-5 daily fractions. The average follow-up time for a brain MRI was 9.8 months.

Most treated lesions were radiosensitive (70.1%) and larger than 1 cm in size (84.2%). 88% of the patients did not have a previous surgical resection. 17.8% of all patients experienced local failure (reappearance of the cancer in and around the original site of the disease) after 12 months and 32.4% experienced local failure after 24 months.

After 12 months, the risk of local failure was 22.1% for large lesions (more than 1 cm) and 13.7% for small lesions (less than or equal to 1 cm). This difference was not statistically significant.

After 12 months, the risk of radionecrosis (death of cancer cells due to radiation) was 7.1% at 1 year and 13.2% at 2 years.  The average overall survival for all patients was 20.5 months.

This study concluded that FSRT was safe and effective in patients with BM of any size with excellent local control.

The study looked back in time at medical records. The sample size was very small. This study only included patients treated at a single institution in Canada.