The UK's "stiff upper lip" culture may explain why it lags behind other countries when it comes to beating cancer, say experts.
Researchers, who surveyed nearly 20,000 adults in six high-income countries, said they found embarrassment often stopped Britons visiting the doctor.
Respondents in the UK were as aware of cancer symptoms as those in Australia, Canada, Denmark, Norway and Sweden, but more reluctant to seek help, they said.
A third feared wasting a doctor's time.
One in six of the men and women aged 50-and-over surveyed in the UK was embarrassed about sharing their symptoms with a doctor, the researchers from King's College London and University College London, with help from Cancer Research UK and Ipsos Mori, found.
They said, in the British Journal of Cancer, that this may partly explain why the UK has a far lower cancer survival rate than other developed nations, despite good access to skilled medical staff and cutting-edge treatments.
The researchers surveyed people in England, Wales and Northern Ireland, but not Scotland.
Data shows that for cancer survival, the UK ranks behind many countries, including the five other nations looked at in the study.
According to estimates, the lives of more than 5,000 cancer patients could be saved each year in England alone if the country matched the best European survival rates.
Former Health Secretary Andrew Lansley pledged to achieve this target by the next general election in 2015, with the government's cancer strategy.
Lead researcher Dr Lindsay Forbes said: "This is a real UK phenomenon. UK people really stood out in our study.
"As a nation we are much more likely to say we are embarrassed about going to the doctor or we are worried that we will take up a doctor's time.
"We don't know why British people feel like that. It may be that we are more stoic and have a war-time mentality.
"We know that older people in particular can get a symptom and then wait for weeks or months before going to see their doctor."
Sara Hiom, of Cancer Research UK, said the charity "and others are working hard to understand and address these potential barriers to early presentation and encourage people to tell their doctor if they have noticed something different about their body".
"More work also needs to be done to tackle the poor awareness that cancer risk increases with age," she added.
The researchers note that Denmark also ranks relatively low for cancer survival. They suspect this could be due to delays in patients accessing timely hospital care - something which may also apply to the UK to some extent.