The Trinity Cancer Center is enrolling patients in an international study that will help determine whether a medication can prevent breast cancer in women who are at an increased risk for the disease.

The study is coordinated by the National Cancer Institute of Canada and has been open there for several years. Now sites are opening in the the United States and Spain. Trinity's site opened this week.

"We're thrilled," said Judy Howell, a cancer prevention research nurse. She hopes to enroll 30 local women in the study, which will include about 4,500 women.

The study is open to post-menopausal women who are over 35 and considered to be at a higher risk for developing breast cancer. Risk factors include the woman's age, when she started menstruation, age when she gave birth to her first live child, personal medical history and relatives with a history of breast cancer, Ms. Howell said.

Women over the age of 60 also are considered to be at high risk because eight in 10 breast cancer cases are found in women 50 or older.

The drug being studied, Exemestane, is in a class of drugs called aromatase inhibitors and is already used for breast cancer treatment.

"This is a new application of a drug that is already approved," said Dr. Costas Constantinou, an oncologist.

It works by reducing the amount of estrogen the body produces. Doctors believe many breast cancers grow with the help of estrogen. Women with a breast cancer diagnosis are given the drug to keep the cancer from recurring.

"This drug is heavily used in Europe," Ms. Howell said.

Two previous studies have resulted in the approval of two drugs for breast cancer prevention,. Those drugs can reduce risk by 50 percent, but both have a side effect of causing blood clots, Dr. Constantinou said.

With this study, 50 percent of women will receive Exemestane and 50 percent will receive a placebo.

It will be a double-blinded study. The patient doesn't know and we don't know either," Dr. Constantinou said. "The idea behind that is remove the bias."

Some may question why doctors would allow a woman to go on a placebo-controlled study when two medications are already approved for breast cancer prevention.

"Many women, after learning about their options they decide not to take any one of those because they are afraid of the side effects," he said. "We know that (Exemestane) has a better safety profile and it doesn't have the side effects that are associated with the other two drugs."

Pre-clinical studies have shown this medication may have a 70 percent chance of reducing breast cancer, Dr. Constantinou said.

"This was never proven from a direct study. This is a study that is going to prove or disprove this and also to show whether it can be done with a lesser risk to women."

"The hopes are this drug will have a better preventative effect for breast cancer and less serious side effects," Ms. Howell said.

Patients enrolled in the study will receive the drug, or placebo, for five years.

"It's great to have something to offer women," Ms. Howell said.

For more information on the study visit www.excelstudy.com

To enroll locally call Judy Howell at 309-779-5059