A trial, published in the New England Journal of Medicine showed that Femara ( Letrozole ) demonstrated a significant advantage in disease-free survival versus Tamoxifen ( Nolvadex ) when used after surgery in postmenopausal women with hormone receptor-positive early breast cancer.

The results were particularly impressive for women at higher risk - with around one third less chance of disease returning in women in this group taking Femara, compared with those taking 'gold standard' Tamoxifen.

The trial showed a 29% reduction in recurrence with Letrozole, compared with Tamoxifen, for those women with breast cancer that had already spread to lymph nodes.
These patients are at the highest risk of breast cancer recurrence and are more likely to develop distant metastases, increasing their risk of dying.

A 28% reduction in risk of recurrence with Letrozole over and above the benefit seen with Tamoxifen, was also seen in those women who had received chemotherapy.

In the same trial, in all women taking Letrozole, there was a 27% reduction in the risk of cancer spreading to other parts of the body and a significant reduction ( 19% ) in the risk of breast cancer returning when compared with those taking Tamoxifen.

The data comes from the Breast International Group ( BIG ) 1-98 trial.
BIG 1-98 is a head-to-head comparison of Letrozole with Tamoxifen involving more than 8,000 postmenopausal women with early breast cancer.

The median follow-up time was 26 months.

The trial divided into the following four arms:

- five years of Letrozole

- five years of Tamoxifen

- two years of Letrozole followed by three of Tamoxifen

- two years of Tamoxifen followed by three years of Letrozole.

Thromboembolism, endometrial cancer, and vaginal bleeding were more common in the Tamoxifen group.
Women given Letrozole had a higher incidence of skeletal and cardiac events and of hypercholesterolemia.

The results published in the NEJM are from the Letrozole and Tamoxifen only ( monotherapy ) arms. Further results from the ongoing arms of the study, due in 2008, are expected to determine which treatment is more effective, monotherapy or sequential therapy, and which sequence is more effective.

Source: The New England Journal of Medicine, 2005


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