Genetic Mutations More Likely in Breast Cancer Found Between Mammograms
Genetic mutations linked to a higher risk of breast cancer, such as mutations in the BRCA1 or BRCA2 genes, were more common in breast cancers found in between regular screening mammograms than they were in breast cancer detected by routine screening.
Doctors call cancers found in between regular screening interval cancers.
The research was published online on Jan. 25, 2024, by the journal JAMA Oncology. Read “Investigation of Genetic Alterations Associated With Interval Breast Cancer.”
About interval breast cancers
The National Cancer Institute defines interval breast cancer as a cancer that is found between a screening mammogram with normal results and the next screening mammogram. A 2020 study found that interval breast cancers often have more aggressive characteristics than cancers found by a routine mammogram. Interval cancers are more likely to be:
Why do the study?
People with a first-degree relative (parent, sibling, child) who’s been diagnosed with breast cancer have a higher risk of interval cancer. This link hints at a genetic cause for interval cancers.
The researchers who did this study wanted to know if interval breast cancers had genetic mutations that were different from breast cancers found by routine screening.
They also wanted to know if the results were the same for breasts that were not dense. The researchers considered interval cancers in non-dense breasts “true” interval cancers because it should be easier to detect cancers in non-dense breasts during routine screening.
About the study
The researchers analyzed information from 9,752 Swedish women ages 40 to 76 who had received mammograms. In Sweden, women who are ages 40 to 74 are invited to have breast cancer screening every two years. Of these women:
1,229 women were diagnosed with interval breast cancer
2,892 women were diagnosed with breast cancer that was found by routine screening
5,631 women had never been diagnosed with breast cancer
Results
Compared with women who had never been diagnosed with breast cancer, women with breast cancer were more likely to have a mutation in any of the 34 genes linked to a higher risk of breast cancer.
Women with interval breast cancer were about 50% more likely to have a mutation in ATM, BRCA1, BRCA2, CHEK2, and PALB2 — the five main breast cancer genes — than women with breast cancer found by routine screening. These women were also more likely to have a family history of breast cancer.
Women with a family history of breast cancer who also had a mutation in any of the five main breast cancer genes were four times more likely to develop interval cancer than to develop cancer that was found by routine screening. Among women who developed interval breast cancer, women with a mutation in any of the five main breast cancer genes had worse survival than women without a mutation in those genes.
“The results of this study suggest that screen-detected and interval cancers possess distinct genetic profiles,” the researchers concluded. “Consequently, these findings may provide insights into the identification of individuals at high risk of developing aggressive forms of breast cancer.”
What this means for you
The results of this study reinforce how important it is to know your personal risk of breast cancer.
In 2023, the American College of Radiology released guidelines saying that all women should have a breast cancer risk assessment by age 25 to figure out if they need to start screening earlier than age 40.
You can do this with your doctor by discussing the following points:
family history of breast or other related cancers (ovarian, melanoma)
any genetic test results for you or other family members
results of past breast biopsies, even if they were benign
personal history of radiation treatment to the face, chest, or both before age 30
breast density
weight
level of physical activity
any use of post-menopausal combined hormone replacement therapy (HRT)
alcohol consumption, if you regularly drink more than three alcoholic beverages a week
the amount of processed food and trans fats you eat
your smoking history
whether or not you have carried a pregnancy to term or have breastfed
If you and your doctor decide you have a higher-than-average risk of developing breast cancer, you can create a screening plan tailored to your unique needs. It may be that you start having annual mammograms earlier than age 40. You also may want to talk to your doctor about whether you need supplemental screening with MRI or ultrasound.
Updated on August 31, 2024