Sixty percent of women taking letrozole showed tumor shrinkage after four months on the drug, whereas 41 percent of women taking tamoxifen showed tumor shrinkage. Patients taking letrozole also underwent fewer mastectomies than women who were taking tamoxifen. Moreover, letrozole actually slowed the rate of cell division -- and hence, tumor growth - better than tamoxifen did, according to cellular studies conducted on the actual tumors. Dr. Ellis cautioned that, while his results are highly significant, they must be replicated in larger and more standard types of studies. The current study design was unique because it examined the drugs' ability to shrink tumors before women had surgery to remove their tumors rather than after surgery, as is commonly done to eradicate any undetected cancer cells. Also, the sample size of 324 women is not large enough upon which to base a change in routine clinical practice, he said. "Although our results are preliminary, letrozole appears to block estrogen more effectively than does tamoxifen, suggesting that letrozole may work for women whose tumors are relatively resistant to tamoxifen," Dr. Ellis said. Letrozole could even replace the more toxic chemotherapy drugs in some patients, or it could be taken together with other non-cytotoxic drugs like Herceptin for maximum effect, the researchers theorize. Its distinct mechanism of action makes letrozole quite different from current therapies like tamoxifen and other, more toxic chemotherapies, Dr. Ellis said. Excerpted from breastcancer.net 12/10/01 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.