Study: Repeated Chest & Cardiac CTs May Increase Breast Cancer Risk
A new study presented on Tuesday at the 2012 Radiological Society of North America (RSNA) annual meeting analyzed the records of approximately 250,000 women and found that increased CT utilization over a ten year period could result in an increase in breast cancer risk for certain women. According to study results, nuclear medicine exams may also contribute to increased breast cancer risk.
As a senior author on the study, led by former UCSF resident Ginger Merry, M.D., M.P.H., at Prentice Women’s Hospital- Northwestern Memorial Hospital in Chicago, we found that among the women enrolled in the integrated healthcare delivery system, CT utilization increased from 99.8 CT scans per 1,000 women in 2000 to 192.4 CT scans per 1,000 women in 2010—an annual increase of 6.8 percent.
When a woman undergoes CT or nuclear medicine imaging of her chest, abdomen or spine, her breast tissue will absorb some radiation. Breast tissue is one of the tissues in the body known to be sensitive to developing cancer as a result of radiation exposure. Until now, the impact of this increased use of imaging on radiation exposure to breast tissue and the subsequent risk of breast cancer has not been known. Our goal was to quantify imaging utilization and radiation exposure to the breast among women enrolled in an integrated healthcare delivery system and to use these data to determine the imaging-related risk of breast cancer from those studies.
We found that the estimated breast radiation doses from CT were highly variable across patients, with the highest doses coming from multiple-phase cardiac and chest CT examinations, where successive images of the organ are captured. By estimating each woman’s 10-year imaging-related risk and underlying risk of breast cancer, we found that young women receiving several chest or cardiac CTs had the greatest increased risk of developing breast cancer.
In order to lower imaging-related risk of breast cancer, radiologists must analyze the radiation doses associated with each exam, reduce the use of multi-phase protocols and employ dose-reduction software where possible to minimize exposure. Women should understand that there is a small but real potential risk of breast cancer associated with cardiac and chest CT, but if imaging is truly indicated, the small risk should not dissuade women from getting the test they need.
To learn more about this research, please see here.