Not All Women Need Digital Mammograms
FRIDAY Jan. 4, 2008 -- Preliminary results from a landmark trial released in 2005 concluded that digital mammography screening was better at catching breast cancers than conventional film mammography was.
But a new study, published this week in the Annals of Internal Medicine, concludes that digital mammography is not cost-effective except when used in younger women or in women with dense breasts.
The new study was part of the original landmark DMIST (Digital Mammographic Imaging Screening Trial), sponsored by the U.S. National Cancer Institute. It included more than 42,000 women in the United States and Canada.
Traditional all-film mammography screening was compared with all-digital mammography screening and with targeted digital mammography screening. The targeted screening referred to age-targeted digital mammography for women under 50, and age- and density-targeted screening for women under 50 or women over 50 with dense breasts.
The study authors compared the screening methods using a measure known as quality-adjusted life year gained, or QALY -- a measurement devised to capture both quality and length of life.
All-digital mammography screening cost $331,000 per QALY relative to film mammography, but it cost more and was less effective than targeted screening. Targeted screening resulted in more detected cancers and fewer deaths than either all-film or all-digital mammography, and the cost-effectiveness ranged from $26,500 per QALY gained to $84,500.
In the Medicare (over 65) population, digital mammography targeted to women with dense breasts ranged from $97,000 per QALY gained to $257,000.
Conventional film mammography was better at detecting breast cancer in older women with non-dense breasts, but the finding was not statistically significant. Because of this finding, digital mammography screening was determined not to be cost-effective for all groups.
But many imaging centers have already switched to digital mammography.
"It's a pragmatic consideration; you have to make a decision. You can't run dual systems," said Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Health System in Baton Rouge, La. "As we're moving to the digital age, you have to make a financial decision."
Most Ochsner sites have converted to digital mammography in the past several years. Brooks' site in Baton Rouge, the last to switch, will be converting within the next 60 to 90 days, he said.
To learn more about the DMIST trial, visit the U.S. National Cancer Institute.
Posted: January 2008