Tiny breast tumors can be aggressive

SAN ANTONIO, Dec. 18 (UPI) -- Certain breast tumors 1 centimeter or smaller may require intensive therapy, U.S. researchers suggested.

Researchers at three Mayo Clinic sites -- Jacksonville, Fla.; Scottsdale, Ariz.; and Rochester, Minn. -- focused on the outcomes of 401 women with "tiny" tumors diagnosed from 2001-05. They found that two types of tumors -- those classified as HER2 positive and triple negative may not depend on size alone.

After three years the cancer came back more frequently in HER2 positive tumors and most frequently in triple negative cancers.

"This is a small study and so we can't make treatment recommendations from it but it appears that biology and not only size matters when it comes to selecting therapy for small, invasive tumors," lead researcher Dr. Surabhi Amar, of the Mayo Clinic in Jacksonville, said in a statement. "Chemotherapy may not work as well as we would like in these tumors but, still, physicians who treat patients with triple negative cancer should be aware of the higher risk of relapse, even if tumors are quite small."

The findings were presented at the San Antonio Breast Cancer Symposium.