Health Secretary Andy Burnham has been urged to apologise to cancer patients who were sent Labour campaign leaflets warning that a Tory government would put their lives at risk.
Personalised cards were sent to 250,000 women saying that the Conservatives would scrap a Labour guarantee that all suspected breast cancer patients would be seen by a specialist within two weeks of GP referral.
The mailshots, which featured a message from a breast cancer survivor praising Labour's policy, referred to the addressee's name several times.
Labour strongly denied that the cards were specifically targeted at cancer patients and said cancer was sadly so prevalent in society that some of the 250,000 people were likely to have suffered from it.
But shadow health secretary Andrew Lansley said he was "rather shocked" by the campaigning.
"It is shameful that the Labour Party, knowing that we are the only party that is going to increase investment in the NHS, have decided to deliberately scare patients and misrepresent what we have said," he said.
"I'm actually rather shocked that they are trying to target breast cancer patients and alarm them by making up stories about what the Conservative Party would do.
"I think Andy Burnham should write to every woman Labour sent these cards to and apologise and withdraw these claims."
A Labour spokesman said: "The Labour Party would never specifically target any material at people suffering from a medical condition. To suggest otherwise is categorically untrue."