The Women's Health Resource. On the web since 1997.

Study: Breast Cancer Patients with Small, HER2-Positive Cancers May Need Additional Treatment (dateline February 19, 2009)


In the largest study of its kind, researchers found that women with a certain type and size of breast cancer tumor may have a poorer prognosis and need additional treatment compared to other breast cancer patients. Specifically, the study showed that women with HER2-positive breast cancers that were one centimeter or smaller had a significant risk of relapse compared with other tumor types. HER2-positive breast cancers are characterized by an overabundance the HER2 (human epidermal growth factor receptor 2) within the cancer cells. Previous research has shown that these cancers can be more aggressive and more difficult to treat than HER2-negative tumors. The current study suggests that women with HER2-postive cancers

HER2 is a protein found on the surface of cells that, when functioning normally, has been found to be a key component in regulating cell growth. However, when the HER2 protein is altered, extra HER2 protein receptors may be produced. This over-expression of HER2 causes increased cell growth and reproduction, often resulting in more aggressive breast cancer cells. HER2 protein over-expression affects approximately 20% to 30% of breast cancer patients. Women with HER2 over-expression may not be as responsive to standard breast cancer treatments, including certain regimens of chemotherapy.

Researchers have been examining HER2-positive breast cancers for the past several years in order to better understand their cancers and develop targeted treatments. To conduct the current study, Ana M. Gonzalez-Angulo, M.D., assistant professor and Ronjay Rakkhit, chief fellow of Hematology-Oncology at M. D. Anderson Cancer Center, at the University of Texas examined medical records of 965 patients diagnosed with HER2-positive breast cancer between 1990 and 2003.

"The current guidelines call for no further therapy if the tumors are less than five millimeters or consider therapy if the tumors are from six to 10 millimeters, but this data challenges that thinking and shows this group of women may benefit from additional therapy," said Ana M. Gonzalez-Angulo, M.D., assistant professor in the Departments of Breast Medical Oncology and Systems Biology at the University of Texas M. D. Anderson Cancer Center (MDACC), in the symposium's news release.

Their findings were as follows:

  • Patients with HER2-positive tumors had 2.68 times greater risk of a breast cancer recurrence and 5.3 times higher the risk of distant recurrence (cancer outside the breast) than those with HER2-negative tumors.
  • Patients with HER2-positive tumors had 5.09 times the risk of recurrence and 7.81 times the risk of distant recurrence compared to patients with HER2-negative tumors.
  • Patients with HER2-positive breast cancers that were one centimeter or smaller had a significant risk of relapse compared with other tumor types.

The findings were validated by two European institutions. The researchers reported the study results at the December 2008 San Antonio Breast Cancer Symposium.

According to Dr. Gonzalez-Angulo, "Patients with HER2-positive tumors one centimeter or less have a significant risk of relapse and should be considered for clinical trials of systemic anti-HER2 therapy, or if a clinical trial is not available, additional therapy should be discussed with them", said Gonzalez-Angulo.

Herceptin and Tykerb are two drugs that may be used to treat breast cancer in these breast cancer patients, in combination with other breast cancer treatments. Tykerb is newly approved by the U.S. Food and Drug Administration (FDA) and is typically used in patients who have already been treated with Herceptin. Other treatments may also be administered.

Additional Resources and References