About 40 percent of breast tumors change when they spread, which means that many patients with metastatic breast cancer may require treatment alterations, say Scottish researchers.
They examined 211 breast tumors that had traveled to the lymph nodes in the armpit. This is the location breast cancer usually spreads to first, BBC News reported. The researchers were surprised to find that the breast cancer had changed in so many patients and in so many ways.
"This suggests there is a need to test which type of disease a woman has in the lymph nodes, because it could radically alter the course of treatment she receives," said lead researcher Dr. Dana Faratian, of the Breakthrough Breast Cancer Research Unit in Edinburgh.
"This research may show why some women whose cancer has spread to the lymph nodes do not respond to treatment," said Professor David Harrison, director of Breakthrough Breast Cancer, BBC News reported.
The study appears in the journal Annals of Oncology.