Less Aggressive Breast Cancer Care?

A new study by Kaiser Permanente researchers suggests that a widely-used regimen to treat breast cancer patients may not necessary work for all patients.

The study focused on 16,975 breast cancer patients who receive care at Kaiser facilities between 2000 and 2006 whose tumors contained a protein known as  human epidermal growth factor receptor 2, or HER2+. When HER2+ protein is present in breast and other forms of cancer, tumor growth tends to be more aggressive.

When those patients with HER2+ tumors that were 0.5 centimeters or less went without chemotherapy or were treated with the antibody trastuzumab, their five-year survival rate was 99%, without a recurrence of the cancer in either the breast or another part of the body. For patients whose tumors were up to 1 centimeter in diameter, the five-year survival rate was still 97%.

The typical treatment for breast cancer patients with the HER2+ protein includes radiation therapy and surgery, although many receive both chemotherapy and antibody treatments as well.

“This is the first large study to demonstrate that the smallest lymph node-negative HER2+ breast cancers have a very low chance of returning,” said Lou Fehrenbacher, M.D., medical director of Kaiser Permanente's oncology clinical trials and an oncologist at Kaiser's Vallejo Medical Center.   “Our results suggest that trastuzumab therapy may not be needed for patients with HER2+ tumors that are 0.5 centimeters in size or smaller, but should be considered for patients with larger tumors, with stronger consideration as the tumor size nears 1 centimeter.” 

The study's findings were published in the most recent issue of the Journal of Clinical Oncology.