DENVER-When physicians are deciding whether to offer stereotactic radiosurgery to patients with multiple brain metastases who have a fairly good functional status, they should consider the total volume of these metastases instead of their number. This was among the key findings of a study presented at the 2005 meeting of the American Society for Therapeutic Radiology and Oncology (abstract 2068).
"Most patients with multiple brain metastases do not receive radiosurgery as a treatment option, given their grim prognoses," Ajay K. Bhat-nagar, MD, a resident physician at the University of Pittsburgh Cancer Institute, said at a poster session. "Typically, patients who have one to three brain metastases are the ones who receive stereotactic radiosurgery in addition to whole-brain radiation ther-apy," he said, but his institution's experience has suggested that radiosurgery confers a survival benefit in at least some patients who have more brain metastases.
John Flickinger, MD, professor of radiation oncology, University of Pittsburgh School of Medicine, was the senior author of the study.
Most of the patients Dr. Bhatnagar and his colleagues studied at their institute had non-small-cell lung cancer (42%), breast cancer (23%), or melanoma (17%), while smaller proportions had renal cell carcinoma (6%), colon cancer (3%), and other or unknown cancers (9%). Sixty-five percent were aged 60 or younger. Importantly, he noted, 85% had a Karnofsky Performance Status score of 70 or higher. By the RTOG recursive partitioning analysis (RPA) classification, 10% fell into class 1, while 75% were in class 2, and 15% in class 3.
The number of brain metastases the patients had ranged widely, from 4 to 18, with a median of 5. Likewise, the total treatment volume varied considerably, from 0.6 to 51.0 cc, with a median of 6.8 cc. Stereotactic radiosurgery, performed in a single session with a gamma knife, was the sole treatment in 17% of patients, was combined with whole-brain radiation therapy in 46%, and was used as salvage therapy after a failure of whole-brain radiation therapy in 38%. The median marginal dose of stereotactic radiation was 16 Gy. Patients had a mean follow-up of 8 months.