National guidelines recommend against using CT, bone and PET scans to look for metastases in women with early stage breast cancer, but a new University of Michigan study found that many of those women are receiving unnecessary tests.

For women with stage I and stage II breast cancer, the chance of finding that it spread to other areas of the body is about one percent, according to the researchers. Thanks to the ABIM Foundation’s Choosing Wisely campaign, the use of imaging among women with stage 0, I and IIA cancers has decreased, but it still remains an issue among women with stage IIB cancer.

The researchers are unsure about why imaging rates remain high for women with newly diagnosed stage IIB breast cancer, but they do speculate about the reasons.
Dr. N. Lynn Henry, lead author of the study and an associate professor of internal medicine at the University of Michigan Medical School, told HCB News that it is likely due to higher use of neoadjuvant chemotherapy in this patient population — women are undergoing imaging before they receive any treatment and the full extent of their disease is not known because they haven't yet had surgery.

"In addition, it is possible that physicians overestimate the risk of metastatic disease in this group of patients," she added. "We are currently investigating the reasons underlying the high rates of imaging for stage IIB disease."

The researchers evaluated CT, bone and PET scans performed on over 29,000 women with early stage breast cancer in Michigan between 2008 and 2014. They determined that up to 60 percent of the scans were unnecessary.

Out of all of the women, 20 percent had at least one imaging exam performed within 90 days of their diagnosis. Furthermore, only 6 percent of the women with stage 0 breast cancer underwent advanced imaging, but 53 percent of women with stage IIB received advanced imaging.

The researchers also uncovered that women who were black or who had hormone receptor-negative or higher grade cancer were more likely to receive advanced imaging.

The study included 25 hospitals in the Michigan Breast Oncology Quality Initiative, which is a Blue Cross Blue Shield of Michigan/Blue Care Network initiative. The rate varied significantly among the different practices included in the study, with over two-thirds of the women with stage II cancer undergoing advanced imaging at some facilities.

In order to curb this issue, research needs to uncover why the imaging is being ordered in the first place.

"If it is primarily physician-driven, then it may be possible to reduce rates using education or by implementing decision tools into electronic ordering systems," said Henry. "Once we identify the key reasons underlying the high rates of imaging, then we will be able to develop targeted interventions."

The findings of this study are consistent with other research that investigated this issue in other parts of the country. Going forward, the researchers are planning on finding the reasons why the exams are being ordered and to develop interventions including patient education and decision tools for physicians.

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