NEW YORK (Reuters Health), Jul 26 - Double reading of mammograms by radiologic technologists in addition to double reading by radiologists -- i.e., quadruple reading -- can improve breast cancer detection without substantially increasing referral rates, Dutch researchers report in the Journal of the National Cancer Institute for August 1st.
Dr. Lucien E. M. Duijm of Catharina Hospital in Eindhoven and colleagues found that this reading strategy increased the cancer detection rate from 5.27 to 5.63 cancers per 1,000 women screened, while increasing the initial referral rate from 1.48% to 1.61%.
In an interview with Reuters Health, Dr. Duijm said that his region, which performs 30,000 to 35,000 readings per year, will soon have screening mammograms read not only by two radiologists (the current standard of care in the Netherlands) but also by two radiologic technologists. An additional four regions also plan to adopt the screening strategy, he added.
The current findings suggest, Dr. Duijm said, that using radiologic technicians as second readers could be helpful in countries, like the U.S., where mammography radiologists are increasingly scarce.
He and his colleagues used quadruple reading for all 61,251 screening mammograms performed at two units from January 1, 2003, to January 1, 2005. Women were followed for two years after the test.
Radiologists referred 905 women for additional testing, 323 of whom were found to have breast cancer. The technologists classified an additional 446 women as positive, resulting in 80 referrals after radiologist review and 22 additional cancers detected.
Referring all radiologist- or technologist-positive readings would have resulted in 1,351 women receiving additional testing, with 362 cancers detected (which includes 17 cancers detected by technologists only).
This would have boosted the radiologist-only cancer detection rate from 5.27 to 5.91 cancers per 1,000, a 12.1% increase, while increasing the referral rate to 2.21%, the researchers point out.
Based on the findings, Duijm said, all women with mammograms deemed suspicious by either radiologist or technologist double reading should be referred for further testing.
In an editorial accompanying the study, Dr. Joann G. Elmore of the University of Washington School of Medicine in Seattle and Dr. R. James Brenner of the University of California, San Francisco School of Medicine point out that just half of U.S. mammography facilities employ double reading by radiologists.
The increased detection rate that double or quadruple reading could offer must be balanced against the resulting increase in recall rates and false-positive tests, they add. "Ultimately, deciding upon the number of readers needed to interpret a screening mammogram will depend on how many readers are available and which outcomes we seek," the editorialists conclude.
By Anne Harding
Last Updated: 2007-07-25 15:00:05 -0400 (Reuters Health)
SOURCE: J Natl Cancer Inst 2007;99:1162-1170
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