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.”
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.
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.
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Hormone therapy is used to prevent the growth, spread, and recurrence of breast cancer.
The female hormone estrogen can increase the growth of breast cancer cells in some women. Hormones help some types of cancer cells to grow, such as breast cancer and prostate cancer.
Hormone therapy may be considered for women whose breast cancers test positive for estrogen or progesterone receptors.
Hormone therapy may be given to block the way the hormone works and help keep the hormone away from the cancer cells (hormone receptors).
An antiestrogen drug frequently used, called tamoxifen (Nolvadex®), blocks the effects of estrogen on the growth of malignant cells in breast tissue.
However, tamoxifen does not stop the production of estrogen. Side effects that may occur when taking tamoxifen include hot flashes, nausea or vomiting, vaginal spotting, fatigue, headaches, and skin rash.
Taking tamoxifen also increases the risk of endometrial cancer (involves the lining of the uterus) and uterine sarcoma (involves muscles of the uterus), both cancers of the uterus. There is also a small risk of blood clots and stroke.
Biological therapy uses the body's own materials, or those made in a laboratory, to assist the body in fighting the cancer. It may also be called biological response modifier therapy, or immunotherapy.
The immunotherapy drug used for breast cancer is called trastuzumab (Herceptin®). This monoclonal antibody works against a protein that encourages breast cancer cells to grow. This drug may be combined with chemotherapy and hormonal therapy.
A growth-promoting protein called HER2/neu is present in small amounts on the surface of normal breast cells and most breast cancers. In some breast cancers, this protein is present in higher amounts and these cancers will tend to be more aggressive. Herceptin attaches to this protein and by doing so, slows the growth of the cancer and, in some cases, shrinks tumors.
Herceptin has only been approved for use in women with metastatic breast cancer. However, studies published in 2005 found that use of Herceptin, along with chemotherapy, in early stage breast cancer may cut the chance of recurrence in half.
Always consult your physician for more information.