Cosmetic breast implants may adversely affect survival in women who develop breast cancer

The authors stress that these findings should be interpreted with caution as some studies did not adjust for other potential confounding factors. They call for further investigations into the long term health effects of breast implants.

Cosmetic breast implants have become increasingly popular, but some studies have suggested that implants can make it more difficult to detect breast cancer at an early stage because they create shadows on mammograms that can obscure some breast tissue.

A team of researchers based in Canada wanted to find out whether the stage at which breast cancer is diagnosed - and post-diagnosis survival - differed between women with and without cosmetic breast implants.

First they analysed the results of 12 observational studies, all published after 1993 and conducted mainly in the US, northern Europe and Canada. They found that women with cosmetic breast implants had a 26% increased risk of being diagnosed at a later stage of breast cancer than women without implants.

They then analysed the results of a further five studies and found that women with cosmetic breast implants had a 38% greater risk of death from breast cancer than women without implants.

However, the authors warn that these findings "should be interpreted with caution as some studies included in the meta-analysis on survival did not adjust for potential confounders."

They point to some study limitations, but say "the accumulating evidence suggests that women with cosmetic breast implants who develop breast cancer have an increased risk of being diagnosed as having non-localized breast tumors more frequently than do women with breast cancer who do not have implants."

Current evidence also suggests that cosmetic breast implants "adversely affect breast cancer specific survival following the diagnosis of such disease," they add.

"Further investigations are warranted into the long term effects of cosmetic breast implants on the detection and prognosis of breast cancer, adjusting for potential confounders," they conclude.