Tumor Size and Type Helps Predict Breast Cancer Outcome

Researchers are making progress in predicting breast cancer risk, recurrence risk, and response to cancer treatment by looking at factors such as breast density and tumor size.

The findings were presented by scientists at the Antonio Breast Cancer Symposium.

The research shows that cancers positive for a protein called HER2 (human epidermal growth factor receptor 2) tend to be more aggressive.

Dr. Ana Gonzalez-Angulo, at MD Anderson Cancer Center says, "Patients with breast cancer tumors that are HER2-positive, even those a centimeter or less in diameter, have a substantially increased risk for relapse.”

HER2-positive Tumors a Concern

Currently, guidelines call for no further treatment after surgery for these small cancers, but Dr. Gonzalez-Angulo notes that additional treatment after surgery should be considered.

She evaluated 965 US patients and validated the results with 350 European patients.

They all had small tumors, one centimeter in diameter or smaller, and 10 percent had HER2-positive tumors.

"The patients who had HER2-positive disease were the ones with the worst prognosis," Dr. Gonzalez- Angulo says.

The five-year recurrence was 23 percent for those with HER-2 positive disease, compared to about 6 percent for those with HER-2 negative disease.

"We should start thinking about adjuvant therapy, as well as clinical trials," she explains. "Twenty-three percent [recurrence] is very high." Adjuvant therapy is additional treatment provided to enhance the effectiveness of a medical treatment, such as chemotherapy following surgery.

The data show that even women with small cancers, under one centimeter, are at risk of recurrence, especially if the tumor is HER2-positive, says Dr. Claudine Isaacs, at Georgetown University Medical Center.

Breast Density and Tamoxifen Success

There has been ongoing debate about how to treat these tumors, according to Dr. Isaacs.

The new study, she says, "adds support to the notion to consider" further treatment.

In other findings reported at the meeting, changes in breast density during treatment with tamoxifen, a drug often used to lower breast cancer risk, can help predict how well the drug is working, says Jack Cuzick, Ph.D., at the Cancer Research UK Centre for Epidemiology, Mathematics and Statistics in London.

He evaluated more than 7,000 participants involved in the International Breast Intervention Study I, assessing their breast density after 12 to 18 months of tamoxifen treatment or placebo treatment (inactive substance), then looking at breast cancer risk.

Breast density is easy and simple to measure on a mammogram, he says, and a useful predictor of breast cancer risk.

Now, based on his findings, it is also a good predictor of response to tamoxifen.

Dr. Isaacs says being able to identify whether a woman is benefiting from the tamoxifen early will allow physicians to consider other treatments.

Always consult your physician for more information.