cancer specialists at the University of Cincinnati (UC) believe that a
drug currently used to treat certain types of breast cancer may also
help prevent the disease from ever developing in the women who are most
vulnerable to it.
Led locally by Zeina Nahleh, MD, this national, phase-3 clinical trial will determine whether exemestane (Aromasin) can prevent the disease in high-risk, postmenopausal women.
Exemestane, approved by the Food and Drug Administration for the treatment of what is known as hormone-receptor-positive breast cancer, is
an aromatase inhibitor, a class of drug that works by blocking the
enzymes that produce the natural female hormone estrogen. Previous
research has shown estrogen promotes the growth of most types of breast
latest approach to breast cancer prevention for patients at elevated
risk focuses on “chemopreventive” drugs like exemestane that reduce the
amount of estrogen produced in the body and, consequently, slow
estrogen-dependent tumor growth.
know exemestane is an effective treatment for existing
estrogen-dependent breast cancer,” says Nahleh, assistant professor and
director of medical breast oncology program in UC’s division of
hematology and oncology. “Now we want to know if the same
chemopreventive drug can halt breast cancer development in high-risk
a continuum of breast cancer prevention options for high-risk
women—ranging from increased screening to the most aggressive choice of
prophylactic surgery,” adds Jennifer Manders, MD, an assistant
professor of surgery at UC and coinvestigator of the study in Cincinnati. “And chemopreventive drugs are right in the middle.”
women who are at high risk of developing breast cancer can take
tamoxifen (Nolvadex), an oral medication that blocks the effects of
estrogen in the cells and minimizes estrogen in the body, as a
has been the only chemoprevention option we've had for reducing the
occurrence of breast cancer in high-risk women,” explains Nahleh, “but
many patients hesitate to take it for fear of serious—though
Those side effects include an increased risk for blood clots, endometrial cancers and significant weight gain.
adds Manders, “it’s up to the patient to decide how much risk she can
tolerate, and then balance her risk for developing breast cancer with
the potential side effects of preventive medicine.”
exemestane can substantially reduce the incidence of breast cancer, the
researchers add, it will give high-risk women another prevention option
that yields fewer negative side effects.
participants are randomized to take either exemestane or a placebo by
mouth daily for five years. Physicians conduct biannual checkups of
study participants to analyze blood samples and screen for signs of
treatment begins, participants undergo a bone mineral test to determine
if they are at elevated risk for low bone density (osteopenia) and bone
fragility (osteoporosis). Those who are at risk may receive medications
in addition to vitamin D or calcium supplements to offset any
density-reducing effects of the trial medication.
UC researchers stress that only postmenopausal women over 40 who are
considered at high risk for breast cancer are eligible for this trial. Risk is calculated on the basis of age, family history of breast cancer, personal medical history, and age at first menstrual cycle and at first live childbirth.
to the American Cancer Society, more than 212,900 women—about 9,600 of
them Ohioans—will be diagnosed with breast cancer in 2006. Invasive
breast cancer, which starts in the milk ducts and invades the
surrounding fatty tissue of the breast, accounts for 80 percent of all
trial is sponsored by the National Cancer Institute of Canada.
Medications are provided at no cost to study participants by Pfizer
Pharmaceuticals. Neither Nahleh nor Manders have any financial interest
in Pfizer Pharmaceuticals.
For more information on UC Cancer Center breast cancer clinical trials call (513) 584-2951.