New Ways to Treat Breast Cancer
A new generation of drugs and treatment options gives patients new hope in the fight against breast cancer.
Targeting Breast Cancers continued...
"Now we can not only offer treatment for something that was untreatable before, we can also help prevent what once was an incurable disease," says Hudis.
Herceptin is FDA approved for metastatic breast cancer that is positive for HER2. However, a number of clinical trials conducted in 2005 revealed that when combined with chemotherapy, Herceptin is similarly effective in treating early-stage HER2-positive breast cancer.
For those who can't take Herceptin, (there is, for example, some evidence it may cause cardiovascular problems in some users), the experimental drug Tykerb may help. Although it works in a slightly different manner, experts say it accomplishes similar results -- and may have treatment advantages of its own.
Although still in clinical trials, Hudis says results are impressive and may facilitate a fast track to FDA approval.
As research into tumor biology continued, doctors soon discovered the hormone-positive breast cancer malignant cells that rely on the female sex hormones, predominantly estrogen, to flourish and grow.
And again, target-specific drugs seemed to be the answer. The first in this category was tamoxifen, which Smith says works by blocking the tumor's ability to use estrogen. While it worked well against hormone-positive cancers, side effects were troubling -- including the risk of blood clots and even other cancers.
More recently, the STAR trial, led by researchers at the University of Texas M.D. Anderson Cancer Center, found an alternative -- the osteoporosisosteoporosis drug Evista. Although this trial focused on prevention of breast cancer, it appears that Evista accomplishes results similar to tamoxifen, with fewer side effects. Experts say it may become another treatment option for some women with hormone-positive breast cancer.
Today, excitement is growing over an even newer approach: drugs known as aromatase inhibitors.
"Aromatase is an enzyme that helps convert steroids to estradiol -- a form of estrogen that makes some breast cancers grow," says Smith. Aromatase inhibitors, she says, are drugs that knock out that enzyme so estradiol can't be made at all, thus inhibiting tumor growth.
The one caveat, says Smith, is that these drugs only work in postmenopausal women, whose estrogen supply comes from this steroid conversion process.