Study Finds Correlation Between Corticosteroids and Breast Cancer

While we know genetic risk is a major component for women diagnosed with breast cancer, current research is exploring how genetic predisposition interacts with medication use.

About 5 to 10 percent of breast cancer cases are the result of genetic mutations passed on by a parent. Mutations in the BRCA1 and BRCA2 genes are the most common cause of hereditary breast cancer, but additional gene mutations include PALB2 and ATM, among others.

Researchers from Weill Cornell Medicine in New York City examined the interaction between medication use and genetic susceptibility to breast cancer, and the study published in the American Journal of Human Genetics had interesting results.

Researchers examined data from the U.K. Biobank, a biomedical database of more than 500,000 participants. The Biobank provides researchers with access to medical and genetic data from volunteers. They can use the data in research studies to improve understanding of the prevention, diagnosis and treatment of various diseases, including breast cancer.

About 5 to 10 percent of breast cancer cases are the result of genetic mutations passed on by a parent.

Polygenic risk scores are used to assess how a person's risk compares to others with different genetic makeup. In the study, the researchers combined two polygenic risk scores to determine the genetic breast cancer risk of more than 212,000 women. Initially, none of the women had breast cancer or a history of breast cancer, but nearly 12,000 developed breast cancer later.

All of the women reported their medications to the Biobank upon being recruited. The researchers used the medication data from the Biobank to examine the pairwise interactions between 96 types of drugs. The team then calculated the risk of breast cancer in women taking specific medications.

What the study indicates

"In this new study, it was suggested that corticosteroids may increase breast cancer risk only in patients with a high genetic risk by influencing breast cancer progression and metastasis," said Sherry Ross, M.D., OB-GYN, a women's health expert at Providence Saint John's Health Center in Santa Monica, California.

"The increased risk may affect specific proteins linked to breast cancer growth and metastasis," Ross added.

Corticosteroids are an anti-inflammatory medicine prescribed for a wide range of conditions, such as asthma, hives, lupus, chronic obstructive pulmonary disease (COPD) and hay fever. They are used to reduce inflammation and suppress the immune system. Examples of corticosteroids include common medications such as hydrocortisone and prednisone.

The study's highlights include:

• Researchers mapped 35 genes as having significant interaction with corticosteroid use.
• Several of these genes are targets of NFE2L2 and its protein, NRF2. It is known that the overexpression of NFE2L2 and NRF2 is linked to the development of breast cancer.
• Researchers found five medication groups, all related to corticosteroids, that had significant interactions.
• Of the women who carried a specific gene that puts them at higher risk of developing breast cancer, 18.2 percent who took corticosteroids developed breast cancer. This compared to 5.1 percent of those who did not take that medication.
• There was no increased risk in women who did not carry the gene that puts them at higher risk of breast cancer.

"This study showed a correlation between taking steroids and breast cancer incidence," said Tara Scott, M.D., chief medical officer at the Revitalize Medical Group in Fairlawn, Ohio, and medical director of integrative medicine at Summa Health Systems in Akron, Ohio. "Although it is an interesting finding, it does not establish causation.

"Steroids are anti-inflammatory, but also, in higher doses, they can suppress the immune system," Scott explained. "In this study, a genetic variant that interacted with corticosteroid use was associated with the increased risk."

What does this mean for women at risk?

"The research suggests that women with an increased genetic predisposition of breast cancer should avoid using corticosteroids," Ross advised. "There are safer corticosteroid alternatives that high-risk women for breast cancer can take for prevention."

If you are worried about taking corticosteroids and know you have a genetic risk of breast cancer, speak to your doctor about alternative options.

While these results are promising, more research is needed. This study still needs to be validated before this suggestion is confirmed.

"If the correlation were better defined, this could be an area that women at risk for breast cancer could modify what they take for inflammation," Scott said.