Many women may be risking their lives by failing to seek early medical help when they spot possible signs of breast cancer, a study suggests.
One in nine women in the UK will develop breast cancer
Doctors at Guy's, King's and St Thomas' Medical School in London questioned 546 women, asking them what they would do if they found possible symptoms.
Just over half said they would seek medical advice immediately.
The remaining women told researchers they would wait - some for two months or more.
Previous studies have shown that women who fail to seek early treatment for breast cancer risk the disease spreading and also have a poorer chance of survival.
Spotting the disease early can significantly increase the chances of beating it.
Women are advised to seek medical advice if they notice the look and feel of their breasts have changed.
This includes a change in outline, shape or size of the breast; puckering or dimpling of the skin; any lump or thickening in the breast or armpit; any flaking skin or discharge from the nipple; and unusual pain or discomfort.
Professor Amanda Ramirez and colleagues sent out a postal questionnaire to 546 women. They were asked at what point they would visit their GP if they noticed changes in the breasts.
Just 58% said they would seek immediate medical help. Some 30% said they would seek help within one week. A further 9% said they would wait one month, while 3% said they would wait two months or more.
Writing in the British Journal of Health Psychology, the researchers said that some women may delay seeking help because they are not fully aware of the symptoms of breast cancer.
"A painless breast lump is the most frequently recognised symptom of breast cancer," they said.
"It may be that limited knowledge of other symptoms of breast cancer leads to the misattribution of these symptoms to a benign process, resulting in delay in seeking medical help."
The researchers said it was important that women were aware of other possible symptoms.
The UK charity Breakthrough Breast Cancer urged women to seek early medical advice if they believe spot changes in the way their breasts look and feel.
"Early detection may help increase your chances of surviving breast cancer but unfortunately there is still confusion about what to look out for and how to check yourself.", says Dr Michelle Barclay.
"Around 80% of breast cancers are found by women themselves.
"This doesn't mean following a strict, complicated routine but simply getting to know what your breasts look and feel like in any way that makes you feel most comfortable - in the bath, shower, when dressing, standing or lying down.
"If you find anything unusual or are worried consult your GP immediately."
One in nine women in the UK will develop breast cancer at some point in her life. More than 40,000 cases are diagnosed each year.