Once they've been diagnosed they are more likely to die and die faster than non-Black women.

"We always say cancer affects everyone, but it doesn't affect everyone equally," said Alpa Patel, a senior vice president at the American Cancer Society.

To understand why, the American Cancer Society Tuesday is launching the largest-ever study of cancer risk and outcomes in Black women.

The Society, which has run other large, long-term studies over the last 70 years, aims to enroll more than 100,000 Black women between the ages of 25 and 55 who are cancer-free and follow them over three decades. They are focusing enrollment in 20 states and the District of Columbia areas where the majority of Black American women live.