Menopause, Not Age, Should Determine Breast Cancer Screening

October 21, 2015
Diagnostic Imaging Staff

Biennial screening mammography may detect more advanced cancers among premenopausal women than annual screening would.

Premenopausal women whose breast cancer was detected through biennial screening mammography have worse prognosis than those whose cancers were found by annual screening, according to an article published in JAMA Oncology.

Researchers from California, Washington, Vermont, New Hampshire, North Carolina, and Georgia performed a prospective study to compare the proportion of breast cancers and their prognostic characteristics between women who underwent biennial screening mammograms and those who underwent annual screening.

Using data from the Breast Cancer Surveillance Consortium, the researchers looked at data from 15,440 women, aged 40 to 85 who had been diagnosed with breast cancer within one year of an annual screening mammogram or two years within a biennial screening mammogram.

The results showed that most cancers were detected in women who were:

Over 50 years old (13,182 - 85.4%)

White (12,063 - 78.1%)

Postmenopausal (9,823 - 63.6%)

Among the 2,027 premenopausal women with cancer (13.1%), those who had been screened every two years had higher proportions of tumors that were stage IIB or higher, were larger than than 15 mm, and had fewer favorable prognostic characteristic compared with the women who were screened every year.[[{"type":"media","view_mode":"media_crop","fid":"42589","attributes":{"alt":"breast imaging ","class":"media-image media-image-right","id":"media_crop_6683944515641","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4624","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 200px; width: 200px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":"©karelnoppe/Shutterstock.com","typeof":"foaf:Image"}}]]

The researchers also looked at postmenopausal women who were taking hormone therapy (HT). Among this group, biennial screeners also tended to have tumors with less favorable prognostic characteristics compared with annual screeners. The authors noted, however, that the differences were not statistically significant.

The proportions of tumors with less favorable prognostic characteristics were also not significantly larger for biennial versus annual screeners among postmenopausal women not taking HT.

The authors concluded that “menopausal status may be more important than age when considering breast cancer screening intervals, which is biologically plausible.”

In a related editorial, Wendy Y. Chen, MD, MPH, from the Dana Farber Cancer Institute, Harvard Medical School, in Boston, MA, wrote that this and other studies have shown that mammography frequency plays a role in the stage at detection of breast cancer. She also pointed out that while these authors did not endorse annual or biennial screening, they implied that postmenopausal women could be screened every two years, but not premenopausal women.

“[W]ith our better understanding of tumor biology and improvements in targeted therapy, the best way to optimize the risk and/or benefit of screening may not be to maximize the chances of finding a smaller tumor,” she wrote. “Instead, efforts should be focused on a better understanding of how screening interacts with tumor biology with a better understanding of the types of interval cancers and sojourn times and how these characteristics differ by age and/or menopausal status.”