Feature | February 12, 2014

Annual Screening Does Not Cut Breast Cancer Deaths, Suggests Canadian Study

Value of breast screening should be reassessed

mammogram, mammography

Photo courtesy of Hologic

Annual screening in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care, concludes a 25-year study from Canada published on bmj.com.

Furthermore, the study shows that 22 percent of screen detected breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received screening in the trial. Over-diagnosis refers to the detection of harmless cancers that will not cause symptoms or death during a patient's lifetime.

Regular mammography screening is done to reduce mortality from breast cancer. Women with small (non-palpable) breast cancer detected by screening have better long term survival than women with palpable breast cancer. But it is not clear whether this survival difference is a consequence of organised screening or of lead time bias (when testing increases perceived survival time without affecting the course of the disease) and over-diagnosis.

So researchers based in Toronto, Canada decided to compare breast cancer incidence and mortality up to 25 years in over 89,000 women aged 40-59 who did or did not undergo mammography screening.

Women in the mammography arm of the trial had a total of five mammography screens (one a year over a five year period), while those in the control arm were not screened.

Women aged 40-49 in the mammography arm – and all women aged 50-59 in both arms – also received annual physical breast examinations. Women aged 40-49 in the control arm received a single examination followed by usual care in the community.

During the 25 year study period, 3,250 women in the mammography arm and 3,133 in the control arm were diagnosed with breast cancer and 500 and 505, respectively, died of breast cancer. "Thus, the cumulative mortality from breast cancer was similar between women in the mammography arm and in the control arm," said the authors.

At the end of the five year screening period, an excess of 142 breast cancers occurred in the mammography arm compared with the control arm, and at 15 years the excess remained at 106 cancers. This, say the authors, implies that 22 percent of the screen detected invasive cancers in the mammography arm were over-diagnosed – that is, one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial.

They stress that these results may not be generalisable to all countries, but say, in technically advanced countries, "our results support the views of some commentators that the rationale for screening by mammography should be urgently reassessed by policy makers."

While they believe that education, early diagnosis, and excellent clinical care should continue, they conclude that annual mammography "does not result in a reduction in breast cancer specific mortality for women aged 40-59 beyond that of physical examination alone or usual care in the community."

In an accompanying editorial, Mette Kalager, M.D., and colleagues believe that long term follow-up does not support screening women under 60.

They agree with the study authors that "the rationale for screening by mammography be urgently reassessed by policy makers," but point out that this is not an easy task "because governments, research funders, scientists, and medical practitioners may have vested interests in continuing activities that are well established."

For more information: www.bmj.com

Related Content

Lunit Unveiling AI-Based Mammography Solution at RSNA 2018
News | Mammography | November 15, 2018
Medical artificial intelligence (AI) software company Lunit will be returning to the 104th Radiological Society of...
Breast Density Advocate Nancy M. Cappello Passes Away

Nancy Cappello. Image courtesy of AreYouDense.org.

News | Breast Density | November 15, 2018 | Jeff Zagoudis, Associate Editor
Imaging Technology News extends its condolences to the family, friends and colleagues of Nancy M. Cappello, Ph.D., who...
Merit Medical Completes Acquisition of Cianna Medical
News | Women's Health | November 14, 2018
Disposable device manufacturer Merit Medical Systems Inc. announced the closing of a definitive merger agreement to...
The MOZART Supra Specimen Tomosynthesis System is the latest generation of 3-D imaging for breast cancer surgery.
News | Breast Imaging | November 08, 2018
KUBTEC announced the launch of a new innovation in the treatment of breast cancer. The Mozart Supra Specimen...
Feature | Breast Imaging | November 07, 2018 | By Jeff Zagoudis
Breast imaging technology has experienced major growth over the last decade or so, and a new report suggests the mark
Philips’ Compressed SENSE technology helps shorten MRI exams by eliminating redundant radiofrequency signals from the acquisition phase. The software reconstructs any missing  information to maintain high image quality. (Images courtesy of Philips/University Hospital Cologne)

Philips’ Compressed SENSE technology helps shorten MRI exams by eliminating redundant radiofrequency signals from the acquisition phase. The software reconstructs any missing information to maintain high image quality. (Images courtesy of Philips/University Hospital Cologne)

Feature | Breast Imaging | November 05, 2018 | By Jeff Zagoudis
The incidence of breast cancer is rising globally, with an estimated 1 in 8 women diagnosed in their lifetime and 40,...
Volpara Enterprise Cloud Reaches 1 Million Mammograms Stored
News | Mammography | October 31, 2018
Volpara Solutions announced that the data stored in the Volpara Enterprise cloud now exceeds 1 million mammographic...
Philips Debuts Integrated Breast Ultrasound Solution
News | Ultrasound Women's Health | October 26, 2018
Philips announced what it calls its ultimate ultrasound solution for breast assessment, available with the Philips Epiq...