THE BREAST CANCER BATTLE RAGES ON.

• Author: Laskowski, Sarah
• Position: MEDICINE & HEALTH

A DIAGNOSIS of breast cancer always is devastating, but advances in research are pushing incidence and mortality trends in the right direction. Over the last decade, the incidence rate has remained level. Most encouraging, the number of deaths decreased by 1.9% per year, amounting to a nearly 20% reduction over that decade.

In fact, indicates Edison Liu, a breast cancer researcher and president and CEO of The Jackson Laboratory (JAX), "If current trends continue, theoretically, there would be no breast cancer mortalities by 2045--and though this remains aspirational and may not be able to be achieved, the direction is clear; we are winning."

What were the medical breakthroughs behind the improvement in prognosis for women with breast cancer? Liu credits "decades of creative innovation," with each generation of scientists building on the findings of the previous one.

An important early insight was that cancer is not a single disease with a single cause, and that the location of a tumor has less bearing on disease progression or mortality than its mechanisms. Better profiling of breast tumors was the first step in developing more-targeted and -effective treatments.

The next big cancer breakthroughs, in the 1960s, were combination chemotherapy (administering multiple drugs simultaneously) and adjuvant therapy (chemotherapy following surgical removal of a tumor, to eliminate any pockets of residual disease). Liu notes that adjuvant therapy was pioneered by researchers working in the Istituto Nazionale Tumori di Milano in Italy.

Before adjuvant therapy, "the standard protocol for breast cancer was draconian surgery followed by draconian radiation," and while a small number of cases still call for such drastic treatment, "adjuvant therapy eliminated the terrible side effects of radical mastectomy followed by disfiguring radiation that actually hurt the patient's health."

Hormone therapy joined the oncologist's toolkit in the 1970s. The hormones estrogen and progesterone promote the growth of some breast cancers. The cells of these so-called hormone-dependent breast cancers contain proteins called hormone receptors that become activated when hormones bind to them, causing changes in certain genes and stimulating cell growth. Hormone therapy to block the body's hormone production is aimed at slowing or stopping the growth of hormone-sensitive tumors.

In 1998, the Food and Drug Administration approved trastuzumab, better known under the brand name Herceptin, to treat breast cancers that are HER2-receptor...