Optimal Duration of Neoadjuvant Letrozole for Breast Cancer Unclear

NEW YORK MAR 17, 2008 (Reuters Health) - Most postmenopausal breast cancer patients undergoing neoadjuvant treatment with the nonsteroidal aromatase inhibitor letrozole experience tumor volume reduction within 4 months, according to the findings of a phase IIb/III trial, but no optimal duration of therapy has yet been established.

Neoadjuvant letrozole effectively reduces tumor volume in locally advanced breast cancers, allowing higher rates of breast conserving surgery, Dr. Diethelm Wallwiener of the University of Tubingen, Germany, and colleagues report in the February 26th publication in BMC Cancer.

To establish the optimal duration of preoperative endocrine therapy, the researchers conducted an open-label trial of letrozole 2.5 mg once daily for 4 to 8 months. The women had locally advanced unilateral primary breast cancer and were ineligible for breast-conserving surgery.

The results of letrozole treatment were analyzed after 4 months in 14 patients and at up to 8 months in 15 patients. Intention-to-treat analysis showed that median tumor size was reduced by 62.5% by month 4 and by 70.0% at the end of the study. Per protocol analysis yielded similar results.

Overall, letrozole was well tolerated and enabled lumpectomy to be performed in more than 70% of the patients, who initially were candidates for mastectomy only.

The researchers conclude that this approach allows more than half of the women who are candidates for mastectomy only to become "eligible for lumpectomy within only 4 months and that prolonged treatment for up to 8 months can result in further tumor volume reduction and, thus, provide incremental benefit to patients."

However, they note that these "exploratory data do not suggest that there is an optimum duration for the preoperative use of letrozole."

SOURCE:

"Reuters content is the intellectual property of Reuters Limited. Any copying, republication or redistribution of Reuters content, including by caching, framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in content, or for any actions taken in reliance thereon."