Sister Study seeks breast cancer’s unknown causes

After watching her sister, cousin and niece fight with breast cancer, Joanne Johnson (left) decided to enroll in the Sister Study, the only long-term medical study of women whose sisters have had the disease. According to Carrissa Dixon (right), a recruitment coordinator for the study, increasing the number of African American participants in the study is important because researchers will “never learn what causes breast cancer in women of color if we’re not well represented.” (Photo: Johnson Daniela Caride; Dixon the Sister Study)

For Joanne Johnson, breast cancer is a family matter.

One of her cousins was diagnosed with the disease about a decade ago. Last year, her niece found out she had it, too.

It rocked Johnson back in 2000, when her sister, Pamela Niles, was diagnosed with breast cancer at the age of 52. After surgery, chemotherapy and radiation treatment, Niles managed to beat the illness.

Unfortunately, according to statistics, many other African American women are not as lucky.

Among black women, breast cancer is the most common type — and accounts for the second highest number of deaths, according to the most recent data released by the American Cancer Society. African Americans also have the highest death rate and shortest survival of any racial and ethnic group in the U.S. for most cancers.

So when Johnson, who has not been diagnosed with breast cancer, heard about the Sister Study — the only long-term medical study of women between the ages of 35 and 74 whose sisters had the disease — she enrolled immediately.

“To lose my sister would have been extremely painful,” says Johnson, 59, a juvenile attorney at Taunton and Attleboro courts. “If there is anything you can do to help your sisters, wouldn’t you want to?”

Conducted by the National Institute of Environmental Health Sciences, the study aims to follow 50,000 female recruits for at least 10 years to research how environmental and genetic factors affect one’s chances of developing breast cancer.

Environmental factors may include diet, exercise, work environment and the level of stress a woman experiences during her typical day. And those factors aren’t necessarily the same for everyone.

“Women of color have different lifestyles from white women,” says Carrissa Dixon, one of the study’s recruitment coordinators.

To ensure that the study’s findings accurately represent U.S. females across the board, recruiters want to increase the number of African American, Latina, Asian, Pacific Islander and Native American participants aged 35-74.

In the Boston area, 158 women have enrolled in the study so far. Only 12 are African American. Five are Hispanic.