Many bowel cancer patients do not get medical help until it is too late, figures show.
One in five is admitted as an emergency, presenting with severe and potentially life-threatening conditions, according to the National Bowel Cancer Audit.
Of 29,000 bowel cancer patients diagnosed in England and Wales between 2010 and 2011, 21.2% were admitted as an emergency.
Nearly a third of these were not suitable for surgical intervention, meaning that their cancer was already too advanced to be operated on, according to the data from the Health and Social Care Information Centre (HSCIC). Of those who were operated on, 11.9% died within 90 days of surgery.
Nigel Scott, audit clinical lead and consultant colorectal surgeon at the Royal Preston Hospital, said: "Bowel cancer emergency admissions are a persistent and very significant health problem.
"Symptom awareness campaigns are useful to break down the taboos of bottoms and bowels that lock these symptoms behind the bathroom door. But emergency surgery continues to be the Cinderella of surgical practice in the UK.
"A recent survey of surgeons highlighted that the NHS pressures currently work against emergency cases, with 55% of surgeons describing inadequate emergency theatre access. Only 15% of emergency surgeons have a comprehensive interventional radiology service out of hours and this deficiency has a major detrimental effect on the use of colonic stenting for the emergency colorectal cancer admission."
The figures from the audit also show that overall the proportion of bowel cancer patients who die following major surgery has fallen for the fourth consecutive year.
In 2010/11, 5.1% of patients had died 90 days on after their operation, compared with 6.4% in 2007/08. But campaigners said that more needs to be done to raise awareness about the disease.
Mark Flannagan, chief executive of charity Beating Bowel Cancer, said: "It is encouraging to see that overall care for bowel cancer patients is largely improving but there are still unacceptable variations in the level of treatment across the board.
"Of big concern is that too many people are being diagnosed as emergency cases. All too often worries and embarrassment mean that too many people aren't aware of the symptoms or they delay seeking help until it's too late and they need emergency surgery when their bowel cancer is at a more advanced stage.
"Much still needs to be done to tackle public attitudes to and understanding of the disease if we are to break the taboo that is bowel cancer."
Public Health Minister Anna Soubry said: "It is encouraging that bowel cancer survival is increasing but numbers being first diagnosed via A&E are concerning.
"We want to help the NHS diagnose bowel cancer much earlier by raising public awareness of the symptoms and supporting GPs to assess people more effectively. Our work to help GPs includes giving them better access to key tests for patients."