Breast implants may delay cancer diagnosis in women, revealed a study on Wednesday and urged a thorough probe into the potential health risks of this type of cosmetic surgery.
In a review of 12 earlier studies of breast cancer patients, a team of epidemiologists from Canada found that women with implants had a 26 percent higher risk of being diagnosed at a later stage of the disease.
This was possibly because implants cast shadows on mammograms, blocking the view of breast tissue.
A separate review of five other studies showed that women with implants also had a 38 percent greater risk of death from breast cancer, said the authors -- likely due to the later diagnosis.
There was no data to suggest that the implants themselves were a cause of cancer.
"The research published to date suggests that cosmetic breast augmentation adversely affects the survival of women who are subsequently diagnosed as having breast cancer," wrote the team.
But they stressed the findings should be interpreted "with caution" as some of the studies included in the meta-analysis may have had scientific shortcomings.
The studies analysed were all published after 1993, mainly in the United States, Europe and Canada.
Commenting on the research, plastic surgeon Fazel Fatah, agreed the findings should be treated with caution.
"This paper does raise however the important issue of possible problems with early diagnosis of localised breast cancer in some women who have breast implants due to difficulty with mammography," he told AFP.
Implants did not prevent women from feeling lumps in their own breasts.
"Further studies are required to see if other forms of breast scanning, such as MRI, could be preferable to mammography in women who have breast implants," said Fatah, a former president of the British Association of Aesthetic Plastic Surgeons.
Added Britain's Breast Cancer Campaign: "We need further robust research before we can say that breast implants impact on survival or that these women may benefit from different screening techniques."
An estimated one in eight women in the United States will be diagnosed with breast cancer at some time in their lives, according to the study.
According to the World Health Organisation, there are about 1.38 million new cases and 458,000 deaths from breast cancer each year -- the most common type of cancer among women.
Breast implants have been at the centre of a global health scare since French company Poly Implant Prothese (PIP) was found in 2010 to be using substandard industrial-grade silicone gel in manufacturing its prostheses.
An estimated 300,000 women in 65 countries are believed to have received PIP implants, which some health authorities say are twice as likely to rupture as other brands -- though officials said there was no proven cancer risk.
The PIP scandal has given rise to several court cases and calls for tougher medical controls.