Aggressive treatment for early breast cancer

A particularly fast-growing form of breast cancer should be treated aggressively after surgery even when tumors are very small, according to recent research that could dramatically alter treatment for women diagnosed with breast cancer.

The research, reported last December at the San Antonio Breast Cancer Symposium, focuses on the 15 percent to 20 percent of women with breast cancer who test positive for an amplification of the HER2 gene, which is typically among the most aggressive forms of the disease. Today, a targeted therapy called Herceptin has greatly improved the odds for women with HER2-positive cancer. Recent studies show the drug reduces the recurrence of these cancers by about half.

But current treatment guidelines do not recommend that the drug be given to women with HER2-positive tumors less than one-half centimeter in size. The guidelines also suggest only that doctors discuss Herceptin treatment with women who have tumors between one-half and one centimeter in size. The latest study finds that women with early-stage small tumors may have much to gain from aggressive treatment. Researchers at the M.D. Anderson Cancer Center reviewed data from 965 women treated between 1990 and 2002 who had tumors less than one centimeter in size. They also studied 350 patients from European institutions.

They found that after five years, 23 percent of women with very small HER2-positive tumors experienced a return of the cancer, compared to just 6 percent of similar women without HER2 disease. That finding indicates that even among women who catch their cancers early, the risk of recurrence is nearly three times greater if they test positive for HER2 than if they do not. None of the women in the study received Herceptin treatment.

Although the data on recurrence strongly suggest that women with early-stage HER2-positive cancer could benefit from aggressive treatment, the study did not study the effectiveness of Herceptin in women with small tumors. Women with small but aggressive tumors should be included in clinical trials comparing current practices with more aggressive treatment, said Dr. Ana M. Gonzalez-Angulo, assistant professor at M.D. Anderson.

Herceptin is a so-called targeted therapy because it attacks particular mechanisms used by tumors to grow or survive. The drug binds to the HER-2 protein and prevents it from being activated. Treatment with Herceptin carries some risks, however, and there are no meaningful data to help women with early-stage disease weigh the risks against the benefits of using the drug.

Herceptin causes flu-like symptoms in about 40 percent of the patients who take it. Of more concern is the fact that Herceptin can damage the heart, and on rare occasions patients who have used the drug experience life-threatening congestive heart failure or stroke.

Source: New York Times