Chemo drug for breast cancer may only benefit a few: study

Wed Oct 10, 8:27 PM ET
A widely prescribed chemotherapy drug does not work for many of the women with breast cancer for whom it is prescribed, according to a study released Wednesday.
The drug Taxol is typically given to women with stage II breast cancer as part of a cocktail of drugs designed to prevent a recurrence of the malignancy.
But US researchers say the drug may only be effective in women with a type of tumour known as an HER2 positive tumour, which occurs in about 20 percent of breast cancer cases.
Writing in the New England Journal of Medicine, the investigators report that women with the more common estrogen-receptor-positive breast cancer do not appear to benefit from Taxol, based on their analysis of previous clinical data.
The researchers say the findings are preliminary and it would be premature for doctors to withhold the drug from patients at this point.
However, if further studies confirm their observations, a simple molecular test could identify the women that would benefit from the medication, sparing others the unpleasant and possibly harmful side effects of unnecessary courses of toxic chemotherapy.
"In general, chemotherapy for breast cancer has been a one-size-fits-all approach," said Daniel Hayes, clinical director of the breast oncology program at the University of Michigan Comprehensive Cancer Center in Ann Arbor.
"Our decision to recommend it is based on whether a woman is at high risk of the breast cancer recurring, without any idea of whether she would benefit from the additional therapy.
"With this data, we hope we will be able to focus chemotherapy on patients whom it's most likely to help," he added.
Hayes based his findings on an analysis of the results of a clinical trial from the 1990s, in which women with breast cancer that had spread to the lymph nodes (stage II breast cancer) were treated with two chemotherapy regimens.
Half of the women got four courses of the chemo drugs Adriamycin and Cytoxan. The other half got four courses of so-called AC chemotherapy, plus a further four cycles of Taxol, which is a protocol used by many oncologists.
The women with HER2 positive tumours were 40 percent less likely to experience a recurrence of their cancer if they were treated with Taxol. The drug did not appear to benefit the women with estrogen-driven tumours.
In addition to suppressing the immune system, and leaving a patient vulnerable to infection, Taxol can also cause a woman's hair to fall out, or prevent it growing back if it has already gone.
It has also been associated with temporary and in some cases long-lasting nerve damage.
Still, Hayes cautioned doctors and patients against dropping the drug just yet, saying that they should stick with the current chemotherapy protocols until his findings could be duplicated in other trials.
"The stakes are too high," he said. But if future studies confirm the findings, "we can really start tailoring treatments to individual patients."