October 13, 2011|By Meredith Cohn, The Baltimore Sun
Personalized medicine means tailoring treatments to a person's specific genetic makeup, but there is limited knowledge so far for breast cancer. But some researchers are taking it a step beyond the search for gene mutations.
Dr. Kala Visvanathan, an associate professor in oncology and epidemiology at Johns Hopkins, is among those looking for other biological markers that could better predict risk for breast cancer. Once new markers are identified, they can also serve as specific targets for therapy.
Now women, particularly those at moderate risk, are less willing to start preventive medications and opt for regular screenings — indeed some of Corbin's family members have eschewed genetic testing and surgery.
"People don't want to take a risk with a pill with side effects if they don't have to," Visvanathan said. "And if they can avoid surgery, even better."
Researchers including Visvanathan also are looking into other therapies that aren't so toxic or invasive. One area of her focus is the sulforaphane in broccoli sprouts. The chemical compound has been shown to prevent breast cancer in animal models, and it can potentially be incorporated into the diet as a food or as a supplement from an early age. The preventive quality could translate to all kinds of breast cancer, including the small subset that doesn't respond to anti-estrogen therapies tamoxifen and aromatase inhibitors.
Visvanathan is looking at sulforaphane's ability to induce protective enzymes in the breast and stop cancer cells from proliferating. In one early study that showed the compound would reach the breasts, women who were scheduled to have breast reduction were given broccoli sprout extract with sulforaphane a half hour before surgery. Another ongoing study in women with cancer is measuring what happens to the sulforaphane once it's in the tissue, urine and blood. And another study is evaluating the impacts on cancer-free women.
"What's impressive about all these drugs [such as tamoxifen and aromatase inhibitors] is they have been used to successfully prevent breast cancer, at least in the short term," she said. "Now we want to fine tune — optimize benefits and minimize side effects so more women at risk will consider such preventive strategies."
There is more fine-tuning going on across the country, and on Hopkins' campus. There, researchers are looking at a hormone from fat tissue called leptin, soy and even older chemotherapy drugs. Dr. Vered Stearns, co-director of the Breast Cancer Program at Hopkins, is looking at the chemo drug Doxil.
In a small sample of women who were about to have mastectomies, Stearns delivered the drug through tiny catheters into the network of ducts that deliver milk to the nipple because this is where breast cancer often develops. If it kills cancer cells, women could prevent disease with treatment once every two to five years or longer.
Doses would be far lower than for traditional chemo treatments and would have less harsh side effects, and the drug would also prevent all types of breast cancer. Stearns is now experimenting with different drugs, including ones more natural than the chemo drug that may be palatable to more women. She's also trying to determine the proper dosage and how long the effects may last.
"I'm very optimistic we may have many different approaches in future," she said. "The challenge is how to implement them and make them attractive and disseminate that. Now we see only women at very high risk, but we're interested in the next step, something acceptable to more women and their physicians."
As for Corbin, she said she would gladly have taken a pill if it would have reduced her odds of developing breast cancer as much as surgery. But for now, she said she made the right choice — a pathology report from her breast tissue showed cancer cells were already forming, and she dodged certain disease within three years.
She wants her daughter, now in her 20s, to have better options in coming years.
"And I have brand new granddaughter, and hope she never has to worry about anything like this at all."
An earlier version misspelled Dr. Vered Stearns' name. The Sun regrets the error.
meredith.cohn@baltsun.com
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Drugs on the market: Tamoxifen and raloxifene, a breast cancer treatment and an osteoporosis drug, block the estrogen tumors use to grow. They reduce risk by 50 percent or less and can have side effects such as blood clots and other kinds of cancer.
Promising studies: Aromatase inhibitors, also used to treat breast cancer, were recently shown in a study to reduce risk by 65 percent in post-menopausal women, but they can cause osteoporosis.
Breast cancer prevention
The gold standard to reduce risk is a mastectomy. Only women at very high risk generally consider this surgery. But there are approved alternatives and others in the works:
In the pipeline: Studies on the chemical compound sulforaphane found in broccoli sprouts, a hormone from fat tissue called leptin, soy and small doses of older chemotherapy drugs are all being explored as less toxic preventive measures, among others.
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