Bowel cancer incidence statistics

Bowel cancer is the 4th most common cancer in the UK, accounting for 12% of all new cancer cases (2015).[1-4]

In males in the UK, bowel cancer is the 3rd most common cancer (13% of all new male cancer cases). In females in the UK it is the 3rd most common cancer (11% of all new female cancer cases).

55% of bowel cancer cases in the UK are in males, and 45% are in females.

Bowel cancer incidence rates (European age-standardised (AS) rates ) are similar to the UK average in all the UK constituent countries.

Bowel Cancer (C18-C20), Number of New Cases, Crude and European Age-Standardised (AS) Incidence Rates per 100,000 Population, UK, 2015

95% LCL and 95% UCL are the 95% lower and upper confidence limits   around the AS Rate 

For bowel cancer, like most cancer types, differences between countries largely reflect risk factor prevalence in years past.

Bowel cancer incidence is strongly related to age, with the highest incidence rates being in older people. In the UK in 2013-2015, on average each year more than 4 in 10 (44%) of new cases were in people aged 75 and over.[1-4] 

Age-specific incidence rates rise steeply from around age 50-54. The highest rates are in the 85 to 89 age group for males and females.

Incidence rates are significantly higher in males than females in a number of (mainly older) age groups. The gap is widest at age 60 to 64, when the age-specific incidence rate is 1.7 times higher in males than females.

Bowel Cancer (C18-C20), Average Number of New Cases per Year and Age-Specific Incidence Rates per 100,000 Population, UK, 2013-2015

95% LCL and 95% UCL are the 95% lower and upper confidence limits   around the AS Rate

For bowel cancer, like other cancer types with a screening programme, incidence increases rapidly at the age screening starts, as prevalent cases are identified. Incidence then tends to return to the usual pattern of gradual increase with age, which largely reflects cell DNA damage accumulating over time. Damage can result from biological processes or from exposure to risk factors. A drop or plateau in incidence in the oldest age groups often indicates reduced diagnostic activity perhaps due to general ill health.

Bowel cancer European age-standardised (AS) incidence rates for males and females combined increased by 1% in the UK between 1993-1995 and 2013-2015.[1-4] The change was of a similar size in males and females.

For males, bowel cancer AS incidence rates in the UK remained stable between 1993-1995 and 2013-2015. For females, bowel cancer AS incidence rates in the UK remained stable between 1993-1995 and 2013-2015.

Over the last decade in the UK (between 2003-2005 and 2013-2015), bowel cancer AS incidence rates for males and females combined remained stable. In males AS incidence rates decreased by 4%, and in females rates increased by 2%.

Bowel Cancer (C18-C20), European Age-Standardised Incidence Rates, UK, 1993-2015

Bowel cancer incidence rates have varied between age groups in males and females combined in the UK since the early 1990s.[1-4] Rates in 25-49s have increased by 33%, in 50-59s have remained stable, in 60-74s have decreased by 4%, in 75-79s have increased by 4%, and in 80+s have remained stable.

Bowel Cancer (C18-C20), European Age-Standardised Incidence Rates, By Age, UK, 1993-2015

For bowel cancer, like most cancer types, incidence trends largely reflect changing prevalence of risk factors and improvements in diagnosis and data recording. Recent incidence trends are influenced by risk factor prevalence in years past, and trends by age group reflect risk factor exposure in birth cohorts.

The introduction of the bowel screening programmes in the mid-2000s probably also plays a part.

Overall stage at diagnosis

A high proportion (87-90%) of bowel cancer cases in England, Scotland and Northern Ireland have stage at diagnosis recorded.[1-3]

More bowel cancer patients with a known stage are diagnosed at a late stage (52-56% are diagnosed at stage III or IV), than an early stage (44-48% are diagnosed at stage I or II). Around 23-26% of bowel cancer patients have metastases at diagnosis (stage IV).[1-3]

The stage distribution for each cancer type will reflect many factors including how the cancer type develops, the way symptoms appear, public awareness of symptoms, how quickly a person goes to see their doctor and how quickly the cancer is recognised and diagnosed by a doctor. It might also relate to whether a national screening programme that can detect early stage disease exists for that cancer type, along with the extent of uptake of that programme.

A cancer type associated with a large proportion of early stage diagnoses could be one that is more likely to be symptomatic at an earlier stage of development, with recognisable symptoms rather than more generic ones.

Bowel Cancer (C18-C20), Proportion of Cases Diagnosed at Each Stage, All Ages, England 2014, Scotland 2014-15, and Northern Ireland 2010-2014

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Stage at diagnosis by deprivation

Late stage at diagnosis of bowel cancer in England is associated with higher deprivation. Among adults aged 15-99 in England, 57% of those in the most deprived areas are diagnosed at stage III or IV, versus 54% of those in the least deprived areas.[4]

Stage at diagnosis by age

Late stage at diagnosis of bowel cancer in England is more common in younger adults (aged 15-59) in England (61% diagnosed at stage III or IV), compared to older adults (aged 80+) (54% diagnosed at stage III or IV) and those aged 60-79 (53% diagnosed at stage III or IV).[4]

Stage at diagnosis by sex

Late stage at diagnosis of bowel cancer is not associated with sex in England.[4]

These patterns by deprivation, age and sex are probably not explained by other demographic differences.[5]

Stage at diagnosis by ethnicity

Late stage at diagnosis for bowel cancer in England is more common in Black Caribbean patients (54% diagnosed at stage III or IV), compared to White British patients (48% diagnosed at stage III or IV) after adjusting for age, sex and deprivation.[6]

The largest proportion of bowel cancer cases occur in the rectum, with slightly smaller proportions in the sigmoid colon and caecum, and a much smaller proportion in the ascending colon (2010-2012).[1-4]

The proportions of cases in the rectum and sigmoid colon are higher in males (31.5% and 23.1%, respectively) than females (23.1% and 20.4%, respectively). In the caecum and ascending colon, the proportions are higher in females (17.2% and 9.8%, respectively) than males (12.2% and 7.3%, respectively), and there are no marked sex differences in other parts of the bowel.[1-4]

A small proportion of cases did not have the specific part of the colon recorded in cancer registry data, or overlapped more than one part.[1-4]

[graph:inc_anatomicalsite_bowel]

More than 90% of bowel cancer cases are adenocarcinomas[glossary - adenocarcinomas] and the majority of these arise from adenomatous polyps (adenomas ). These common benign tumours develop from normal colonic mucosa and are present in about a third of the European and USA populations.[1]

The more difficult to detect flat adenomas account for about 10% of all lesions and may have a greater propensity to malignant change.[2,3]

Only a small proportion of polyps (1-10%) develop into invasive bowel cancer.[4] Indicators for progression from adenomas to cancer include large size, villous histology and severe dysplasia .[5]

Bowel cancer incidence rates are projected to fall by 11% in the UK between 2014 and 2035, to 74 cases per 100,000 people by 2035.[1] This includes a larger decrease for males than for females.

For males, bowel cancer European age-standardised (AS) incidence rates in the UK are projected to fall by 15% between 2014 and 2035, to 87 cases per 100,000 by 2035.[1] For females, rates are projected to fall by 7% between 2014 and 2035, to 63 cases per 100,000 by 2035.[1]

Bowel cancer (C18-C20), Observed and Projected Age-Standardised Incidence Rates, by Sex, UK, 1979-2035

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It is projected that 53,646 cases of bowel cancer (29,356 in males, 24,290 in females) will be diagnosed in the UK in 2035.

There is evidence for a small association between bowel cancer incidence and deprivation for males in England, while there is no evidence for an association for females.[1] England-wide data for 2006-2010 show European age-standardised incidence rates are 13% higher for males living in the most deprived areas compared with the least deprived, while for females the rates are similar for those living in the least and most deprived areas.[1]

Bowel Cancer (C18-C20), European Age-Standardised Incidence Rates by Deprivation Quintile, England, 2006-2010

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The estimated deprivation gradient in bowel cancer incidence for males and females living in the most and least deprived areas in England has not changed in the period 1996-2010. It has been estimated that there would have been around 770 fewer bowel cancer cases each year in England during 2006-2010 if all people experienced the same incidence rates as the least deprived.[1]

Age-standardised rates for White males with bowel cancer range from 54.1 to 55.3 per 100,000. Rates for Asian males are significantly lower, ranging from 19.1 to 28.0 per 100,000 and the rates for Black males are also significantly lower, ranging from 29.7 to 43.8 per 100,000. For females there is a similar pattern - the age-standardised rates for White females range from 34.0 to 34.8 per 100,000, and rates for Asian and Black females are also significantly lower ranging from 11.3 to 17.5 per 100,000 and 20.4 to 31.6 per 100,000 respectively.[1]

Ranges are given because of the analysis methodology used to account for missing and unknown data. For bowel cancer, 146,495 cases were identified; 17% had no known ethnicity.

An estimated 230,200 people who had been diagnosed with bowel cancer between 1991 and 2010 were alive in the UK at the end of 2010.[1]