Do women with non-cancerous breast conditions eventually get cancer?

Susan Dudley, PhD, Cancer Prevention and Treatment Fund

In addition to the more than 200,000 women who are diagnosed with breast cancer in the U.S. every year, even more women are told they have an abnormal breast condition that is not cancer.

These conditions may be discovered by the woman herself, by a doctor’s examination, or by a mammogram. Sometimes it is not possible to make an accurate diagnosis until a biopsy is done to remove a tissue sample that can be examined in a laboratory.

Lumps that are not cancer include 1) cysts that are filled with fluid, or 2) fibroadenomas, which are smooth, and hard, often feeling like a marble under the skin. There can also be thickened but harmless areas called pseudo-lumps. White spots that show up on a mammogram are called microcalcification, and may also require a biopsy. Since only 1 in 12 breast lumps is cancerous, and only 20% of microcalcifications are related to cancer, most women get good news after a breast biopsy.

Doctors know that the overall risk for breast cancer increases with age. For a woman in her 20’s in the United States, the risk is very low. By the time she reaches her 70’s, her chance of breast cancer is 1 in 7. But does having one of these non-cancerous conditions change those odds?

Some of them may – but doctors have not known how much risk one of these abnormal conditions adds. Now, a study by Dr. Lynn Hartmann and her colleagues, published in the New England Journal of Medicine can help women and their doctors understand which specific breast conditions add to a woman’s risk, and which ones don’t.[1]

The study included more than 9,000 women who had biopsies for suspicious breast conditions that turned out not to be cancer. Afterward, the researchers monitored their health for approximately 15 years. In that time, 8% of the women developed breast cancer. It turned out that specific changes in breast cells that could be seen in the first non-cancerous biopsy could help predict which women were most likely to get breast cancer.

  • The biopsies from about two-thirds of the women showed that the cells were growing and reproducing at a normal rate, and were changing in ways that are not dangerous. This is called nonproliferative fibrocystic change. The risk of developing breast cancer in the next 15 years was not increased for these women unless their mother, sister, or daughter had the disease.
  • Similar predictable cell changes were found in the biopsies from another 30% of the women. But in this group, the cells were growing and reproducing too fast. This is called proliferative fibrocystic change. In this group, the risk of developing breast cancer over the next 15 years increased from about 5 cases in 100 women with normal cells, to about 9 cases of breast cancer in 100 women with proliferative fibrocystic changes.
  • Less than 4% of the women with non-cancerous biopsies had changes in their breast cells that were very abnormal and cells that were growing and reproducing too fast. This is called proliferative fibrocyctic change with atypia. Their risk of developing breast cancer in the next 15 years increased from about 5 in 100 to about 19 in 100.

For all these groups, the risks are higher if the non-cancerous condition occurred when the woman was very young – in her thirties or forties. A strong family history of breast cancer can also increase the risks for later developing the disease.

Almost all of the women in this study were white, so we can’t be sure that the risks are the same for other racial groups. Still, the results will help women and their doctors decide whether they need to get more frequent breast cancer screening or to take other preventive measures after they have had non-cancerous breast disease.

References:

  1. Hartmann, LC, et al. (2005). Benign Breast Diesease and the Risk of Breast Cancer. New England Journal of Medicine, July 21, 2005, pages 229-237