Jan. 27, 2004 -- It's been a concern: Could tumors hide behind breast implants, growing undetected in mammograms? But a new study shows that, with new imaging techniques and self-checks, lumps can indeed be detected at an early stage.
"The good news is, even though mammography doesn't find cancer well in women with implants, it doesn't seem to result in more advanced cancers at diagnosis," Diana L. Miglioretti, PhD, assistant investigator at the Group Health Cooperative in Seattle, tells WebMD.
Her study appears in this week's issue of The Journal of the American Medical Association (JAMA).
Her finding disputes two recent studies, which found that women with breast implants tended to have later-state disease compared with other women, reports Miglioretti.
However, since the 1980s, special mammography procedures have been developed to obtain better images when breast implants are involved, she explains.
"This is the first really big study of this issue ... It answers an important question," Carl D'Orsi, MD, director of the breast imaging center at the Winship Cancer Institute at Emory University in Atlanta, tells WebMD.
"For years, there's been the feeling that the cancers might be bigger, that we might miss them. There are only small studies that were difficult to say with any degree of confidence if they were true or not. This is good news."
Tumors of Similar Size, Stage
Miglioretti's study compared mammography data from seven cancer registries around the country, comparing 141 women with implants and 20,738 without -- all of whom were diagnosed with breast cancer.
She also matched records of more than 1e million women with nobreast cancer diagnosis -- 10,849 with implants and 1,016,684 without implants.
"We found that screening mammography missed 55% of the cancers in women with implants compared with 33% of women without implants," Miglioretti tells WebMD.
However, despite mammography's lower accuracy for detecting tumors, the tumors found in women with implants were "of similar stage, size, nodal status, and estrogen-receptor status and lower grade" compared with women without implants, she adds.
The Problem With Mammography
"A breast implant is radio-opaque, meaning it shows up as a solid white mass on the mammogram, which blocks the breast tissue," Miglioretti tells WebMD.
For these women, the mammogram procedure involves special "implant displacement views" -- which means manipulating the implants, pushing them toward the back, and pulling the normal breast tissue forward.
"This does reveal more breast tissue, but not all," says Miglioretti.
Yet her study showed that women with breast implants "actually have smaller tumors" when diagnosed, she explains. "This means they're finding them some other way besides mammography."
"It could be that the breast implant provides a firm surface that pushes tissue up against the skin, so it might be easier to feel the lump," she says.
Also, because there is less natural breast tissue, lumps might be easier to feel. "Women with implants are told to check their breasts often," says Miglioretti. "Women might be finding them earlier. Or they may be more body conscious and go to the doctor earlier when they find something."