Cutting-Edge Breast Cancer Therapy
There's no doubt that breast cancer treatment has made great strides in
recent years. A diagnosis of breast cancer is no longer a death sentence, and
the treatment is no longer more painful than the disease. Today, women with
breast cancer live longer -- and better -- than ever before. Many are
completely cured. And the future looks even brighter, with individualized,
cutting-edge therapies being tested and developed right now.
Hitting the Target
Future breast cancer treatments will be a lot smarter about the
cells they target. Older approaches -- standard chemotherapy and radiation --
tend to attack all rapidly dividing cells throughout the body. That includes
healthy cells lining the hair follicles and the intestines, as well as cancer
cells. Yes, the approach can work, but it also causes many of traditional
chemotherapy's infamous side effects.
But researchers have learned that breast cancers, like people,
are not identical. And they've been using this knowledge to develop more
effective, less toxic drugs. By discovering precisely how tumors differ
from person to person, they've begun creating treatments that seek out and
destroy specific types of cancer cells, and only those cancer cells -- leaving
healthy cells alone.
"Why is it that in one patient, breast cancer acts one way
-- after chemotherapy, the cancer never recurs -- while in another patient with
the same [size and type of tumors], after surgery and chemotherapy, the cancer
comes back? It's probably due in large part to fundamental genetic differences
in the tumors," says Eric Winer, MD, head of the Dana-Farber Cancer
Institute's Breast Oncology Program in Boston.
We've already learned, for example, that some breast cancers
rely on the female hormones estrogen and progesterone to grow. In women with
these so-called estrogen- and progesterone-receptor (ER and PR) positive
cancers, blocking the activity of the hormones can stop growth or even shrink
the tumor. Tamoxifen was a breakthrough when it was developed and it’s remained
the standard hormone-blocking drug for years. But a newer kind of hormonal
medication called aromatase inhibitors -- such as Arimidex and Femara, as well
as Aromasin, a similar type of drug -- may be even more effective. While they
were originally approved only for cases where Tamoxifen had failed, both
Arimidex and Femara are now approved as a first line of defense. Arimidex has
also been approved by the FDA to treat not only advanced cancer, but early
breast cancer as well.
Hormonal cancer medications even work as preventative medicine:
the FDA has recently approved the use of Tamoxifen in women who don’t yet have
breast cancer but are at high risk of developing it within a few years.
ER and PR positive cancers aren’t the only targets. Some
cancers, instead, have particularly high levels of a protein called HER2. The
drug Herceptin, a monoclonal antibody, attacks this protein and effectively
fights the cancer. Herceptin has proven so useful that it’s being moved earlier
and earlier in the treatment regimen; several studies have shown the Herceptin
is highly effective (when combined with a cancer drug called Navalbene) in
women with early breast cancer even before surgery.
And experts predict that these targeted therapies are just the
beginning. "There's much more beyond HER2 and ER-PR status," says
Winer. "The hope is that we'll be able to identify a greater number of
subtypes of breast cancer, and ... we'll have a much clearer sense of the
benefits of different kinds of treatments. At the same time, that information
is going to allow us to develop new and more targeted treatments."