A gift of time
New drugs extend survival in advanced disease
The reasons are not entirely clear, but the trend could not be more welcome: breast cancer deaths in the United States have been declining for a number of years. Most likely, catching tumors earlier through mammography screening has helped, along with greater use of hormonal drugs like tamoxifen and improved chemotherapy to prevent recurrences following surgery.
But credit should also go, say Dana-Farber experts, to more potent yet gentler drugs, some of them in pill form, for fighting cancer that has spread beyond the breast, known as metastatic or Stage IV disease. Systemic treatments — therapies delivered to the entire body — can not cure advanced breast cancer, but they can prolong lives, sometimes dramatically, and enable women to be more comfortable and active.
"I believe that some of the reduction in mortality over the last five years is related to improvements in treating metastatic disease," says Eric Winer, MD, director of the Breast Oncology Center at Dana-Farber (part of Dana-Farber/Brigham and Women's Cancer Center). "We're extending lives, and doing so with less toxicity than in the past."
The most dramatic breast cancer treatment advance in the last decade is Herceptin,
one of the first "targeted" drugs that attack specific genetic control
points in cancer cells without harming normal tissue most of the time. In about
25 percent of women with breast cancer, a mutated gene called HER-2/neu sets
off excess signals that spur the tumor's out-of-control growth. Tumors
containing this altered gene are more aggressive and harder to treat than those
without it.
In the early 1990s, after the role of the abnormal HER-2/neu gene in aggressive
breast cancers was discovered, scientists rapidly developed a drug that could
latch on to a receptor that exists only in HER-2/neu-positive breast cancer
cells, thereby shutting down the cells' growth and even shrinking tumors.
By 1998, after an exceptionally quick bench-to-bedside journey, Herceptin had
been tested and speedily approved to treat advanced breast cancers with this
mutant gene.
- Next: How Herceptin works
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