Taxol-type Drugs Give Slight Boost to Survival Rates in Early Breast Cancer

The breast cancer drugs called taxanes, which include Taxol (paclitaxel) and Taxotere (docetaxel), increase survival rates when used as part of chemotherapy following surgery for cancers that have not spread, according to a new review of the research.

The review, which compared chemotherapy regimes using taxanes with those that did not, comprised 12 studies including 21,191 women.

“For patients, this study confirms that including taxanes in an adjuvant chemotherapy regimen for early breast cancer will improve their chance of living longer and remaining free of breast cancer,” said review coauthor, Anna Nowak, M.D. “It also provides reassurance that there are many different ways of giving a taxane and that the individual choice of regimen may not be critical.”

Taxanes increased overall survival by 2.6 percent and survival with no recurrence of the cancer by 4.1 percent, when compared to regimens without taxanes, the reviewers found.

Although the data appear to show that docetaxel is slightly better, this type of analysis cannot compare one drug to another accurately. “This hypothesis would be better tested in a clinical trial directly comparing the two drugs. Such trials are being done,” said Nowak, a medical oncologist at the University of Sydney in Australia.

The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

Some researchers have argued that taxanes themselves are no better than other kinds of chemotherapy for breast cancer — and that the results of previous trials just showed that more and longer chemotherapy in general was better.

“These have been past criticisms of some of the earlier taxane trials,” Nowak said. “I think that hypothesis has been disproved by this study.”

“It looks like taxanes are beneficial,” said Kay Dickersin, Ph.D., director of the Center for Clinical Trials at Johns Hopkins School of Medicine. Dickersin, who was not involved with the review, said that the studies analyzed appeared to be of good quality, which strengthens the result.

“For physicians, the study also demonstrates that there are numerous effective regimens and that there is no clear message that taxanes must be given together with anthracyclines, or as an extra drug, or for a longer number of cycles. This allows physicians to tailor the regimen to the individual patient in terms of side effects, duration and convenience,” Nowak said.

She added that there was no increase in secondary leukemia associated with these drugs, at least during the patient follow-up periods so far, which had been a concern.