Trastuzumab prolongs survival in HER2+ metastatic breast cancer

NEW YORK (Reuters Health) - Treating HER-2 positive, metastatic breast cancer with trastuzumab significantly increased survival in a retrospective study, to the point were such women given the drug had higher survival rates than similar women with HER2-negative disease.

Senior author Dr. Sharon H. Giordano, from the University of Texas M.D. Anderson Cancer Center in Houston, and associates used a prospectively maintained database at that institution to analyze outcomes for 2091 women diagnosed with metastatic breast cancer of known HER2 status between 1991 and 2007. Median follow-up was 16.9 months (range 0 to 176 months).

As reported in an early release issue of the Journal of Clinical Oncology, most patients had HER2-negative disease (1782, 85.2%). Of the remainder, 191 (9.1%) had HER2-positive disease and received first-line trastuzumab, and 118 (5.6%) had HER2-positive disease but did not receive trastuzumab. Median age ranged from 48 to 52 years. Median cumulative time on trastuzumab was 11.6 months (range 0.23 to 68.2 months).

One-year overall survival was 86.6% in the HER2-positive trastuzumab group, 75.1% in the HER2-negative group, and 70.2% in the HER2-positive without trastuzumab group. Corresponding rates at 2 years were 63.2%, 54.9%, and 41.3%.

In a model adjusted for patient and tumor characteristics and year of diagnosis, women with HER2-positive disease who received trastuzumab had a 44% decreased risk of death compared with women with HER2-negative disease. They also had a 55% decreased risk during the first 2 years compared with HER2-positive patients not given trastuzumab.

These findings, Dr. Giordano and colleagues maintain, emphasize that "trastuzumab is now the standard of care among patients with HER2/neu-positive disease."

They note that optimal duration of trastuzumab treatment remains to be established, as well as the long-term effect of the agent on the incidence of central nervous system metastases.

"Regardless," the investigators conclude, "the introduction of trastuzumab into the treatment paradigm of women with HER2/neu-positive breast cancer is probably the most important breakthrough in the management of breast cancer seen this decade."

They add: "With the advent of other forms of targeted therapy currently under study, we are bound to see even more improvement in prognostic outcomes of women with breast cancer."

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