Could cosmetic breast implants interfere with the early detection of breast cancer and worsen a woman's chances of survival?
That is the question being raised by new Canadian research based on an analysis of previously published studies.
The researchers, led by Eric Lavigne of Laval University, combed through the medical literature, looking for studies that focused on breast-cancer patients who had received breast implants before their diagnosis.
They found 12 studies dealing with the timing of diagnosis. The studies, involving more than 1,000 women with breast cancer, were all published after 1993 and carried out mainly in the United States, Europe and Canada. A meta-analysis of the combined data suggests that women with implants had a greater risk of being diagnosed at a later stage of breast cancer than women without implants.
There is no evidence the implants cause cancer, but they might hinder detection, the researchers speculated in their study published this week on the website of the British Medical Journal.
"The implant itself makes mammography much more complicated," said the senior author of the study, Dr. Jacques Brisson, a professor of epidemiology at Laval University.
He added that an early-stage tumour might be missed on the mammogram because of the presence of implants, which are filled with saline solution or silicone. While there are techniques X-ray technicians can use to compensate for the implants, there is still a risk a small tumour may go undetected, he said. Such a delay in diagnosis could allow the cancer to spread, making the disease harder to treat.
To pursue this line of logic, the researchers also analyzed five studies dealing with survival rates. That assessment suggests women with breast implants had a slightly greater risk of death from breast cancer than women without implants.
Brisson noted the average five-year survival rate for women diagnosed with breast cancer in Canada is about 88 per cent. Having an implant could push down that survival rate to 84 per cent, the new analysis indicates.
"It is not a major reduction in survival, but some women might want to take that into consideration when they are planning to have implants," said Brisson.
He also said the findings need to be viewed with caution until they can be confirmed by additional studies. Indeed, the researchers were limited in their efforts by a dearth of data.
"There are very few studies that have looked at survival of breast-cancer patient with implants," said Brisson. "When you do these kinds of comparisons you have to take into consideration possible differences between women with implants, compared to women without implants and this was not done very extensively in most of these five studies."
Lavigne hopes the study will prompt other researchers to turn their attention to breast cancer in women with implants.
"Cosmetic breast augmentation has become increasingly popular. In the United States, for example, cosmetic breast augmentation was the most commonly performed cosmetic surgical procedure in 2011; 307,000 surgeries were performed, an increase of approximately 800 per cent compared with the early 1990s," the researchers write in their study. (Breast augmentation is also among the most commonly performed cosmetic surgeries in Canada.)
"An estimated one in eight U.S. women will be diagnosed as having breast cancer at some time in their lives. Therefore, some women with breast implants will eventually develop breast cancer, which raises concerns about the possible effects of implants on detection of breast cancer."