An independent review into breast cancer screening has been launched amid concerns that the diagnostic process could be more harmful than beneficial.

Last month researchers from the Nordic Cochrane Centre in Denmark claimed women given mammograms were being "misinformed" and not told about the risk of overdiagnosis.

A London-based consultant raised similar concerns, sparking questions over the value of breast cancer screening, which the NHS argues saves lives.

Professor Sir Mike Richards, national cancer director at theDepartment of Health, announced in the British Medical Journal(BMJ) that he had begun a review to weigh up the evidence.

"I take the current controversy very seriously," he wrote in a letter in the journal.

An open letter published in the BMJ last month by Professor Susan Bewley, consultant obstetrician at King's College, London, said NHS leaflets on screening "exaggerated benefits and did not spell out the risks".

"The oft-repeated statement that '1,400 lives a year are saved' has not been subjected to proper scrutiny. Even cancer charities use lower estimates," the letter stated.

"The distress of overdiagnosis and decision making when finding lesions that might, or might not, be cancer that might, or might not, require mutilating surgery is increasingly being exposed," it added.

Responding to the letter, Richards said he would examine the available evidence for and against screening.

"I will do my best to achieve consensus on the evidence, though I realise this may not ultimately be possible," he wrote.

"Should the independent review conclude that the balance of harms outweighs the benefits of breast screening, I will have no hesitation in referring the findings to the UK National Screening Committee and then ministers."

The review will be led jointly by Richards and Cancer Research UK.

Sara Hiom, director of health information at the cancer charity, said: "Women need more accurate, evidence-based and clear information to be able to make an informed choice about breast screening," she said.

"The decision whether to be screened is a personal one, but that decision should be made with all of the potential harms and benefits fully explained."

A Department of Health spokesman stressed that NHS advice had not changed and urged women to go for screening when invited.

"The best available evidence shows that screening saves lives by detecting cancers earlier than they would otherwise have been," he said.

"Our screening programme has always been regularly scrutinised and evaluated."