Women with early, HER2-positive breast cancers who received Herceptin and conventional chemotherapy were half as likely to have a recurrence as women with similar tumors who received only chemotherapy in recent studies.

Some doctors are hailing the findings as a major advance in treating breast cancer -- the second-most-deadly cancer in US women, behind lung cancer -- although results apply to only a small subset of patients.

"Clearly, the results ... are not evolutionary but revolutionary," Gabriel Hortobagyi, director of the breast cancer program at Houston's MD Anderson Cancer Center, writes in an editorial that accompanies the studies in The New England Journal of Medicine.

The 'Cure' Word

Jo Anne Zujewski, who directs breast cancer therapy research at the National Cancer Institute (NCI), which financed two of the studies, says the findings support her belief that breast cancer has become curable in increasing numbers of women. "I am using the 'cure' word," Zujewski said Wednesday, adding that "it's not like we now have a cure and yesterday we didn't. This is one more group of women who used to have a poor prognosis and now have a good prognosis."

But Barbara Brenner of Breast Cancer Action, an education and advocacy group, called use of the word "cure" in this case "outrageous," because the studies on average followed women for only a year or two.

Researchers reported on the studies in May at an American Society of Clinical Oncology meeting, but today's publication provides the first detailed look at the treatment, which costs roughly $48,000 a year.

Herceptin targets a gene called HER2, which causes an overproduction of a particular protein in about 20% of invasive breast tumors. HER2-positive tumors are more likely to have spread to nearby lymph nodes and less likely to have receptors for the hormones estrogen and progesterone -- both characteristics that are linked to a greater risk of recurrence and death.

The new studies found that women with early, HER2-positive breast cancers who received Herceptin and conventional chemotherapy were half as likely to have a recurrence as women with similar tumors who received only chemotherapy. "On the basis of these results, our care of patients with HER2-positive breast cancer must change today," Hortobagyi writes.

Congestive Heart Failure

Herceptin was approved for treating metastatic HER2-positive breast cancers in 1998, but once a drug is on the market, doctors can prescribe it to any patient they see fit. Until the presentations in May, though, cancer specialists were reluctant to prescribe Herceptin to patients with early HER2-positive tumors "because there is a real risk of side effects," Zujewski says.

Clinical trials in women with advanced disease found that those who received Herceptin and chemotherapy had as much as a 16% risk of developing congestive heart failure, which can be fatal, according to Hortobagyi's editorial.

In the two NCI-sponsored trials in early breast cancer, a total of 51 women who received Herceptin and chemotherapy developed symptomatic congestive heart failure, compared with four women who received chemo alone. In the third trial, 29 women on Herceptin and chemo and one woman on chemo alone developed heart failure. Hortobagyi called for longer follow-up of women in the trials to see whether their heart problems are reversible.