New treatments offer alternative to breast cancer chemotherapy
An experimental chemotherapy drug called Abraxane was more effective in treating advanced cases of breast cancer and carried fewer side effects than its widely used cousin, Taxol, according to a study released Monday. In another chemotherapy-related study released Friday, the drug docetaxel--widely used for late-stage breast cancer since the mid 1990s--was found to be dramatically better at battling a common early-stage form of the disease than fluorouracil, long a standard treatment. Research by the Breast Cancer International Research Group determined that five years after initial treatment, the docetaxel patients had a 28% lower risk of recurrence than the fluorouracil patients. John Mackey, a breast cancer specialist at the University of Alberta in Canada and a co-leader of the docetaxel study, said the two studies, presented at a breast cancer conference in San Antonio, could soon prompt changes for recommendations in breast-cancer chemotherapy. "People change their (drug recommendations) based on a 2% to 3% improvement," he noted.
A study involving 454 women with breast cancer that had spread elsewhere in the body found that 33% of tumors responded to Abraxane, compared with 19% for Taxol. Abraxane also slowed tumor growth significantly in those patients. Both Taxol and Abraxane are derived from paclitaxel, which works by interfering with a cancer cell's ability to divide. A big difference is how they make their way through the body, and thus how large the dosage can be. Taxol is combined with an oil-based solvent known as Cremophor, whose often harsh side effects limit how much paclitaxel can be delivered to a patient per treatment session. Abraxane, on the other hand, hitches a ride on the naturally occurring human protein albumin, allowing researchers to administer about 60% more paclitaxel per treatment. This approach "allows us, for the first time, to fully maximize the tried-and-true power of paclitaxel," said William Gradishar, a Northwestern University medical professor and a co-director of the study.
The docetaxel study involved nearly 1,500 pre- and post-menopausal women in 20 countries with early-stage breast cancer that had spread into the lymph nodes in the armpit. After five years, 75% of the docetaxel patients had not developed new breast cancer, compared with 68% the fluorouracil patients. Using statistical analysis, the researchers calculated that the chances of relapse using docetaxel are 28% lower than with the other drug.