Every year, thousands of women are diagnosed with breast cancer. Even among women with small breast cancers, survival rates vary greatly between women of different ethnicities. A study published in JAMA looked at 450,000 women with breast cancer of various stages and sizes, finding that compared to white women, black women were 1.5 to 2 times more likely die of a small breast cancer, while a Chinese or Japanese woman was half as likely to die from a similar tumor. Experts stressed the importance of taking a woman’s ethnicity into account when seeking to provide optimal treatment, noting that the course of the cancer can be very different depending on race and ethnicity.