Women With HER2-Positive Breast Cancer Should Be Treated Aggressively, Researchers Report

Main Category: Breast Cancer
Article Date: 17 Dec 2008 - 7:00 PDT

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Women with breast cancer who test positive for the HER2 gene -- one of the most aggressive forms of the disease -- should be treated aggressively after surgery, even in cases where present tumors are very small, researchers said Friday at the San Antonio Breast Cancer Symposium, the New York Times reports. Focusing on women with HER2 forms of breast cancer, researchers from the University of Texas M.D. Anderson Cancer Center reviewed data from 965 women who had tumors less than one centimeter in size and who were treated between 1992 and 2002. In addition, they reviewed data from 350 European patients (Parker-Pope, New York Times, 12/13). Reuters reports that 10% of the women had HER2 tumors and that they were at an increased risk of recurrence compared with women who had estrogen receptor-positive tumors or women with triple-negative tumors (Fox, Reuters, 12/12).

The study found that 23% of the 965 women with small tumors experienced a recurrence after surgery within five years, compared with 6% of similar women without HER2 forms of the disease. Their findings suggest that the risk for recurrence is three times greater among women with HER2 breast cancer than women without the gene. The Times reports that none of the women in the study underwent Herceptin treatment.

Fifteen percent to 20% of women with breast cancer test positive for the HER2 form of the disease, according to the Times. A targeted treatment for HER2 breast cancer is available with Herceptin -- manufactured by Genentech -- which has been shown to reduce the recurrence of HER2-positive cancer by half. Current treatment guidelines, however, do not recommend the treatment for women with tumors less than one-half centimeter in size.

Although the study did not examine the effectiveness of Herceptin in women with small tumors, the data on recurrence strongly suggests that women with early-stage HER2-positive cancer could benefit from aggressive treatment, the Times reports. According to Ana Gonzalez-Angulo -- an assistant professor at M.D. Anderson who led the study -- women with small but rapidly progressing tumors should be included in clinical trials that compare current practices with aggressive therapy (New York Times, 12/13).

Additional Studies

Additional studies were reported during the San Antonio Breast Cancer Conference. Summaries appear below.

~ Hormone Replacement Therapy: Women who take HRT -- including estrogen and progestin -- for five years double their risk of breast cancer, researchers reported on Saturday, the AP/Minneapolis Star Tribune reports. According to the first phase of a federal study conducted by the Women's Health Initiative and led by Rowan Chlebowski of the Harbor-University of California-Los Angeles Medical Center, women who took HRT for five-and-a-half years experienced an average 26% increased risk of breast cancer. The second part of the study -- during which researchers tracked 15,387 women through July 2005 and mapped breast cancer cases as they occurred -- found that risk increased with the start of HRT use, peaked when the study ended and decreased as nearly all users stopped taking the therapy. The study also found that when women stopped taking HRT, their risk for breast cancer decreased and returned to a normal level after about two years. The findings indicate that the risks of HRT outweigh the benefits for most women and that HRT should only be used to relieve moderate to severe menopausal symptoms at the lowest dose and shortest amount of time possible, according to the researchers (Marchione, AP/Minneapolis Star Tribune, 12/13).

~ Screening Schedules: Researchers at the University of Texas M.D. Anderson Cancer Center reported Saturday that an alternating breast cancer screening schedule might better detect early stages of breast cancer in women at a high-risk for the disease than an annual exam, Reuters reports. The study used a screening schedule that alternated between a mammogram and an MRI every six months for two years. Eighty-six women out of a total of 334 at a high risk of breast cancer were placed on the rotating schedule. Among these 86 women, nine cases of cancer were detected, with an MRI detecting five of the cases and a mammogram and MRI detecting three. One very early-stage cancer case was missed by both methods but detected through a later exam. The researchers found that the MRI was able to detect the majority of the cases. Huong Le-Petross, who presented the findings, said that the study highlights the greater sensitivity of MRI screening for women at a high risk of breast cancer and suggests that the new screening schedule might increase the chance of detecting cancers earlier (Steenhuysen, Reuters, 12/13).

~ New Risk Assessment Test: A new risk assessment test for breast cancer, called OncoVue and manufactured by InterGenetics, is more effective than the risk assessment test currently used by physicians, according to a study presented Friday, the AP/Long Island Newsday reports. The test looks for 22-single letter variations in 19 genes that have been linked to breast cancer and costs $397. It also considers personal factors such as age and childbearing. The test classified 50% more women as having a high risk of breast cancer than the current test and properly scored other women with a lower risk. However, some advocates for improved breast cancer prevention and detection methods say that gene tests are not a "good idea until more is known about the best treatment options," the AP/Newsday reports. OncoVue is only offered through physicians in 33 sites nationwide (AP/Long Island Newsday, 12/12).

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