In a study of 167 patients who underwent radiation therapy for invasive breast cancer after surgical staging of their tumors, researchers at the Seattle Cancer Care Alliance and University of Washington Medical Center in Seattle found that the tumors' physiological information shown on MRI scans correlated with surgically based findings of cancer having spread to lymph nodes.

The finding suggests that breast MRI could help determine if women scheduled to undergo surgery will later need radiation therapy, and how much they will need.

Lead author Dr. Christopher Loiselle said decisions on radiation therapy in the past were made after surgery and before chemotherapy, but more women may currently be treated with chemotherapy before surgery.

The ultimate benefit is that some women can be spared radiation therapy, especially those with smaller tumors and tumors that have not spread to the lymph nodes, Loiselle said.

The findings were presented at the annual meeting of the American Society for Therapeutic Radiology and Oncology in Boston.