Breast Cancer: New Risk Assessment Breakthrough
Doctors can now use a known link between breast cancer and benign breast disease (BBD) to identify women who are at a greater risk of developing cancer. Researcher Jeffery Tice at the University of California San Francisco has improved the predictive powers of a widely used breast cancer screening model by including BBD as a risk factor. New treatment options for at-risk patients include preemptive chemoprevention drugs.
Benign Breast Disease
Benign breast diseases (BBDs) are noncancerous disorders that can affect the breast. Researchers have long known that women with certain types of benign breast disease are at increased risk of developing breast cancer, but Tice’s work was the first to include BBD as a factor in breast cancer screening, according to the study published by the Journal of Clinical Oncology in August 2015. Tice built upon existing data culled from 1.1 million women ranging in age from 35 to 74 years who received a mammogram.
While not all abnormal breast conditions elevate the incidence of cancer, others increase risk by as much as 10 times. According to the American Cancer Society, an overgrowth of cells in the breast ducts or lobules called hyperplasia increases the risk of developing breast cancer from one and a half to five times the average rate, depending on whether the cell pattern appears atypical. Lobular carcinoma in situ describes a condition where atypical cells grow in the breast lobules of milk-producing glands but don’t spread outside of the lobules. This pattern of abnormal cell growth increases a woman’s risk from between seven to 11 times.
An Updated Model
Doctor Jeffery Tice incorporated these risk-elevating benign breast diseases into the risk calculator created by the Breast Cancer Surveillance Consortium. The BCSC calculator is a tool for healthcare professionals that aims to evaluate a woman’s risk of developing breast cancer within the next five years by evaluating her age, race, family history and breast density readings from mammograms. To this list, Tice added the known incidences of benign breast disease, based on the 17 percent of women in the study who had undergone a breast biopsy in addition to mammography.
Tice’s addition of BBD increased the number of women identified with a five year risk rate from 9.3 percent to 27.7 percent. The accuracy was also high. Though the BCSC calculator slightly overpredicted the disease rate, the expected outcome correlated closely with the observed data with a ratio of 1.04 to 1.
Chemoprevention for Women At Risk
In addition to changes in diet and lifestyle, those who have a high risk for breast cancer have a new option to avoid cancer known as chemoprevention. Not to be confused with chemotherapy, chemoprevention uses targeted drugs to lower the risk for certain kinds of cancers. For breast cancer, the treatment uses drugs that block the effects of the hormone estrogen on breast tissue, including tamoxifen and raloxifene. These estrogen receptor modulators, or SERMs, reduce the incidence of breast cancer by as much as 38 percent, according to the Washington Post.
The drugs are not without risks including blood clots and strokes, and in the case of the more widely used tamoxifen, uterine cancer. However, lead researcher Jeffrey Tice believes better risk models and screening can improve outcomes by helping physicians decide which of their patients are most likely to benefit from SERMs. “For these women, the benefits of medications that prevent breast cancer generally outweigh the harms,” Tice told UC San Francisco in the university’s newsletter.
Doctors and researchers have high hopes that advances in breast cancer screening and prevention can lower the incidence of the disease, which currently kills approximately 40,000 women every year; however, questions still remain, including what the risk threshold should be for chemoprevention. Overly conservative recommendations could lead to millions of women taking unnecessary drugs, particularly older women who automatically score higher on the risk models. Improvements in risk calculators such as Tice’s can help doctors prescribe chemoprevention more responsibly and ultimately save more lives with less risk.