More than half of Britons who have a possible cancer symptom do not contact their GP over fears they won't be able to get an appointment, a damning poll has revealed.
According to a YouGov survey for Cancer Research UK, two in five also delayed a visit because they did not want to be seen as making a fuss.
Experts today warned that the worrying delays could damage the chances of survival.
Being diagnosed early can help people survive cancer but the chances of this happening reduce significantly if people don't tell their doctor about unusual changes to their health or possible cancer symptoms.
When bowel cancer, for example, is diagnosed at stage one -- its earliest stage -- more than nine in 10 people will survive it for five years or more.
This likelihood stands at just one in 10 when diagnosed at stage four, the latest stage.
In response to the poll, Cancer Research UK has now trained Tesco pharmacists to help spot possible signs and symptoms of cancer and enable patients to speak to pharmacists in private if they need to.
Pharmacists will be able to offer guidance on taking the next steps and booking a GP appointment if needed.
Steve Browne, a father-of-three told how he was fortunate his bowel cancer was caught in its early stages despite putting off visiting his GP for months
The now 59-year-old who lives with his wife and has three grown-up children, dismissed his symptoms having been diagnosed with irritable bowel syndrome many years previously
Michelle Mitchell, Cancer Research UK's chief executive, said: 'Nearly one in two of us will be diagnosed with cancer in our lifetime.
'Spotting cancer early can make all the difference, so it's incredibly important that people get the support they need when they notice something that's not right for them.
'That's why we've joined forces with Tesco, to make it easier for people to talk to a professional about any concerns, and ultimately, to help diagnose cancers earlier and save lives.'
Tom Lye, Tesco health and wellness category director, said: 'We know how many barriers there can be in day-to-day life around getting health concerns checked out.
'Customers can quickly and easily see a pharmacist at one of over 350 Tesco Pharmacies.
'Informed by their specialist Cancer Research UK training, pharmacists can have a confidential conversation about any worrying symptoms which could support customers in getting an earlier cancer diagnosis.'
Professor Peter Johnson, NHS national clinical director for cancer, also said: 'The NHS is seeing and treating record numbers of people for cancer, with more people diagnosed at an earlier stage than ever before.
'I know that coming forward for a potential check for cancer can be daunting but it could save your life.
'So, if you notice any unusual changes in your health or have any concerns about potential cancer symptoms, please contact your GP, pharmacist or another healthcare professional as soon as possible.'
Cancer Research UK's poll surveyed 6,844 British adults to understand what prevented people getting help the last time they spotted something that could have been a sign of cancer.
It found the top reasons were thinking it would be difficult to get an appointment -- cited by 53 per cent of people -- and finding it difficult to get an appointment (47 per cent).
Not thinking the symptom would be anything serious (44 per cent) and deciding they could manage the symptom themselves (43 per cent) followed.
Some 40 per cent did not want to be seen as making a fuss.
More than a third (37 per cent) also thought their symptom was related to an existing illness, condition or life change, while 37 per cent said did not want a remote appointment.
Fast access to cancer care not only reduces the chance of the disease spreading to other areas of the body, it can also mean a patient doesn't need as extensive treatments like chemotherapy or radiotherapy for as long.
One recent study by Canadian researchers estimated that a 4-week delay to cancer surgery led to a 6-8 per cent increased risk of dying.
It comes as one father-of-three told how he was fortunate his bowel cancer was caught in its early stages despite putting off visiting his GP for months.
Steve Browne, from London, suddenly began experiencing intermittent bleeding and stomach pain in 2012, aged 45.
The now 59-year-old who lives with his wife and has three grown-up children dismissed his symptoms having been diagnosed with irritable bowel syndrome many years previously.
It was only after finally booking a GP appointment months later, at the request of his wife, that he discovered the cancer and underwent surgery.
He said: 'We need a kick to get checked out, and my wife was the one who sent me to the doctor after I told her all my symptoms.'
'I was lucky as the cancer was caught early and it had not spread. I needed surgery but did not have to have chemotherapy or radiotherapy.
‘I spent some time at home recovering from the surgery, supported by my family and started a phased return to my work as a surveyor just a few months later.
‘If there is one message that I would like to share it would be that early diagnosis is so important.
‘So if you notice something that’s not right for you, just make sure you talk to a health professional about it.’
There are around 44,000 cases of bowel cancer every year in the UK and 142,000 in the US, making it the fourth most common cancer in both countries.
Symptoms often include changes in bowel movements such as consistent and new diarrhoea or constipation, needing or feeling the need to poo more or less frequently and blood in the stool.
Stomach pain, a lump in the stomach, bloating, unexpected weight-loss and fatigue are among other signs.
NHS bosses have long argued they are seeing more patients than ever as part of the fight against cancer, despite a slump in cancer performance statistics.
But despite the importance of fast access to diagnosis and treatment in improving outcomes, other cancer performance figures show the NHS is still failing to meet targets.
Latest figures for September, released last week, show that just 67.9 per cent of newly-diagnosed cancer patients referred for urgent treatment were seen within two months -- the target is 85 per cent.
Meanwhile, only 91.2 per cent of patients started treatment within 31 days of being booked in September, below the goal of 96 per cent.
The health service target of telling at least 75 per cent of patients with suspected cancer they do or don't have the disease, equally, wasn't met at 73.9 per cent.