West Midlands Key Health Data 2008/09
CHAPTER SIX: COLON CANCER IN THE WEST MIDLANDS
Catherine Bray, Dr Timothy Evans, Kay Gill, Dr Gill Lawrence, Richard Oakes and Sally Vernon:
Main Body
7: Environment And Health – Outdoor Air Pollution
9: Predictors Of Emergency Department Use At Neighbourhood Level In The West Midlands
6.1.1 Colon Cancer – Introduction
In 2006 colon cancer was the fourth most common cancer in England and responsible for 9% of all new cases of cancer (excluding non melanoma skin cancer)1. Colon cancer is more common in men than in women; in 2006 in England, the number of men diagnosed with colon cancer was 9,770 (age standardised rate: 32 per 100,000) compared to 9,313 women (age standardised rate: 23 per 100,000)1. The majority of those diagnosed are over 65 with risk increasing with age. Although colon cancer is primarily a disease of the elderly, 24% of colon cancer patients diagnosed in England are under 651.
Colon cancer was responsible for over 6% of cancer deaths in England in 20051. More than 80% of colon cancer deaths in England occur in people aged 65 and over, and more than 40% in those aged 80 and over1. In 2005 there were 8,360 deaths from colon cancer in England; 4,207 men and 4,153 women. The Age Standardised Rate (ASR) for men was 13 deaths per 100,000 population compared with 9 deaths per 100,000 women1. Whilst incidence rates have changed little over the past ten years, colon cancer mortality has been falling since the early 1990s. Between 1990 and 2005, the colon cancer age-standardised mortality rates in England fell by 33%1.
Since the early 1970s there has been a considerable improvement in one and five-year survival rates for individuals diagnosed with colon cancer. One-year relative survival rates rose from around 40% in the early 1970s to 67% for both sexes in the late 1990s. The 5-year relative survival rate for colon cancer rose from 22 and 23% for males and females respectively diagnosed in the early 1970s to 47 and 48% in the late 1990s. Ten-year survival rates are only a little lower than those at five-years indicating that most patients who survive for five years are generally cured from this disease. Nationally, 5-year survival is at least 5% higher for the most affluent patients diagnosed with colon cancer compared with those from the most deprived groups2.
6.1.2 Risk Factors
A number of risk factors can influence the likelihood of an individual developing colon cancer. These include:
Diet - Red meat and processed meat have been linked by several studies to an increased risk of colon cancer. Less than 10g of fibre daily also increases the risk. Eating fish on a regular basis has been shown to reduce risk. A low fat diet offers no significant protection against colon cancer, although it is believed that reducing total calorie intake may lower the risk2,3.
Alcohol consumption – Excess alcohol intake (45g/day or more) increases the risk of developing colon cancer; quantity rather than type (for instance beer or wine) is a more significant risk factor2.
Obesity - Being overweight results in a higher risk of colon cancer, although the risk is greater in men than in women. Obese men are approximately 50% more likely to develop colon cancer. This risk is reduced with increased levels of physical exercise over time.2,3
Genetics - Fewer than 5% of colon cancers are linked to a genetic inheritance; although individuals with an immediate family member with colon cancer are approximately twice as likely to develop the cancer. The risk is increased further if the relative is young at diagnosis or there is more than one first-degree relative diagnosed with colon cancer3
6.2 Epidemiology
6.2.1 Incidence and Mortality
The data presented here are taken from the West Midlands Cancer Registry database, 2006 data. Mortality data are from the ONS, with the most recent data available from 2005 at the time of production.
In the West Midlands in 2006, 2,026 cases of colon cancer were diagnosed; 1,029 in males and 997 in females (Table 6.1). The crude incidence rates (number of cases per 100,000 population) in males and females were similar (40.0 per 100,000 and 36.6 per 100,000 respectively) but the age standardised incidence rate in males (30.9 per 100,000) was 1.3 times higher than that in females (23.4 per 100,000).
In 2005, there were 937 deaths from colon cancer in the West Midlands: 495 in males and 442 in females. The crude mortality rate in males was higher than that in females (18.8 per 100,000 in males compared with 16.2 per 100,000 in females) and the age standardised incidence rate in males (14.8 per 100,000) was 1.6 times higher than that in females (9.3 per 100,000).
The differences between crude and age adjusted incidence and mortality rates arise because colon cancer is primarily a disease of the elderly and, as women generally have a longer life expectancy than men, there are more elderly women than elderly men in the West Midlands population. Age adjusted rates correct for these differences in age distribution, allowing comparisons of incidence and mortality rates in populations with the same age structure.
Table 6.1: Colon cancer incidence and mortality in the West Midlands and England4
West Midlands Incidence Source: Cancer Registration database, CNET Reports_2008 extract. West Midlands Mortality Source: Office of National Statistics Crown copyright 2008 supplied under MRP Data access agreement 1052/2007. Data for England taken from the National Cancer Information Service: CIS 4.2d.003: July 2008 refresh (1985-2006 data).
In 2006, the overall age standardised colon cancer incidence rate in the West Midlands was very similar at 26.7 per 100,000 than that for England (27.3 per 100,000). Age standardised colon cancer incidence rates in the male and female population in the West Midlands were also similar to those in England (30.9 per 100,000 compared with 31.5 per 100,000 for males and 23.4 per 100,000 compared with 23.1 per 100,000 for females).
In 2005, the overall age standardised mortality rate for colon cancer in the West Midlands was very similar at 11.7 per 100,000 compared to that for England (11.4 per 100,000). Age standardised colon cancer mortality rates in the male and female population in the West Midlands were also similar to those in England (14.8 per 100,000 compared with 13.4 per 100,000 for males and 9.3 per 100,000 compared to 9.5 per 100,000 for females).
6.2.2 Incidence and Mortality Age Profiles in the West Midlands
Figures 6.1a and 6.1b show how colon cancer incidence rates in 2006 and colon cancer mortality rates in 2005 varied with age group and gender in the West Midlands. Colon cancer incidence rates increased rapidly in men and women aged 60 and above; with 83% of colon cancers being diagnosed in men over 60 and 84% diagnosed in women over 60. Colon cancer mortality rates also increased rapidly in older men and women; with 78% of colon cancer deaths in men and 82% of colon cancer deaths women occurring in those aged 65 or over. The median age of diagnosis was 73 for males and 76 for females, and the median age of death was 75 for males and 80 for females.
Figure 6.1a: Age specific incidence rates for colon cancer in 2006 and mortality rates in 2005 in the West Midlands, males
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Figure 6.1b: Age specific incidence rates for colon cancer in 2006 and mortality rates in 2005 in the West Midlands, females
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Figures 6.2a and 6.2b show how the numbers of colon cancers diagnosed in 2006 and the number of deaths from colon cancer in 2005 varied with age group and gender in the West Midlands.
Figure 6.2a: Age profile for number of cases of colon cancer in 2006 and the number of deaths from colon cancer in 2005 in the West Midlands, males
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Figure 6.2b: Age profile for number of cases of colon cancer in 2006 and the number of deaths from colon cancer in 2005 in the West Midlands, females
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6.2.3 Incidence and Mortality Trends in the West Midlands
Figures 6.3a and 6.3b show changes in age standardised incidence rates between 1992 and 2006 and mortality rates between 1992 and 2005 in the West Midlands for males and females respectively. Age standardised incidence rates in males and females have decreased by 13% and 11% respectively since 1992 (from 35.7 per 100,000 to 30.9 per 100,000 in males and from 26.5 per 100,000 to 23.4 per 100,000 in females). Age standardised mortality rates in males and females have decreased by 23% and 40% respectively since 1992 (from 19.2 per 100,000 to 14.8 per 100,000 in males and from 15.6 per 100,000 to 9.3 per 100,000 in females). There was a statistically significant negative correlation with time for incidence and mortality in males and females.
Figure 6.3a: Incidence and mortality trends in the West Midlands, males Dotted lines represent 95% confidence intervals
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Figure 6.3b: Incidence and mortality trends in the West Midlands, females
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6.2.4 Variation in Incidence with Deprivation in the West Midlands
Figure 6.4 shows how age standardised colon cancer incidence rates in males and females varied with deprivation group in 2006. Colon cancer patients were allocated to five deprivation groups on the basis of deprivation scores calculated from the income domain of the Index of Deprivation for 2007 (ID2007). Although the age standardised incidence rates for colon cancer were higher (33.4 per 100,000) in males in the most deprived group compared with those in the most affluent group (28.8 per 100,000), there is no statistically significant relationship between colon cancer incidence and deprivation. There is also no distinctive or statistically significant relationship between colon cancer incidence and deprivation in females.
Figure 6.4: Variation with deprivation group in incidence rates for colon cancer diagnosed in 2006, males and females
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6.2.5 Incidence Rates in PCTs
Figures 6.5a and 6.5b show funnel plots of the age standardised colon cancer incidence rates in West Midlands PCTs for males and females in 2006. None of the PCTs had a colon cancer incidence rate in males which was significantly higher or lower than the West Midlands average of 30.9 per 100,000. However, at 14.9 per 100,000, the incidence rate for females in Solihull Care Trust was significantly lower than the West Midlands average of 23.4 per 100,000, and at 32.4 per 100,000, the incidence rate for females in South Birmingham PCT was significantly higher than the West Midlands average.
6.2.6 Mortality Rates in PCTs
Figures 6.6a and 6.6b show funnel plots of the age standardised colon cancer mortality rates in West Midlands PCTs for males and females in 2005. There were no PCTs with a colon cancer mortality rate in males which was significantly higher or lower than the West Midlands average of 14.8 per 100,000. For females, the mortality rate in Heart of Birmingham tPCT (3.7 per 100,000) was significantly lower than the West Midlands (9.3 per 100,000). None of the PCTs had a colon cancer mortality rate in females which was significantly higher than the West Midlands average.
6.2.7 Mortality/Incidence Rate Ratios in PCTs
Figures 6.7a and 6.7b show funnel plots of age standardised colon cancer mortality/incidence rate ratios in West Midlands PCTs for males and females. In order to maintain comparability, incidence and mortality data are for 2005. The mortality/incidence rate ratios for colon cancers diagnosed in 2005 in males and females in the West Midlands region were 0.44 and 0.45 respectively. Wolverhampton City PCT had the highest mortality/incidence rate ratios in males (0.60) and North Staffordshire had the highest mortality/incidence rate ratio in females (0.59). The lowest mortality/incidence rate ratio in males (0.25) occurred in Telford & Wrekin PCT and Solihull Care Trust. None of the PCTs had a significantly higher or lower mortality/incidence rate ratio in males compared to the West Midlands average. Heart of Birmingham tPCT had the lowest mortality/incidence rate ratio in females (0.26) and this was significantly lower than the West Midlands average. None of the PCTs had a significantly higher mortality/incidence rate ratio in females compared to the West Midlands average.
Figure 6.5a: Variation in colon cancer incidence rates in West Midlands PCTs, males Colon cancers diagnosed in 2006 in males in each PCT
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Figure 6.5b: Variation in colon cancer incidence rates in West Midlands PCTs, females Colon cancers diagnosed in 2006 in females in each PCT
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Figure 6.6a: Variation in colon cancer mortality rates in West Midlands PCTs, males Colon cancer deaths in 2005 in males in each PCT
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Figure 6.6b: Variation in colon cancer mortality rates in West Midlands PCTs, femalesColon cancer deaths in 2005 in females in each PCT
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Figure 6.7a: Variation in colon cancer mortality/incidence rate ratios in West Midlands PCTs, males Colon cancer cases diagnosed in 2005 and deaths in 2005 in males in each PCT
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Figure 6.7b: Variation in colon cancer mortality/ incidence rate ratios in West Midlands PCTs, femalesColon cancer cases diagnosed in 2005 and deaths in 2005 in females in each PCT
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6.3.1 Survival
Figure 6.8 shows that males and females diagnosed with colon cancer have very similar 1-year, 5-year and 10-year relative survival rates. One-year relative survival rates for males and females diagnosed with colon cancer in 2001-2005 in the West Midlands were 69% and 67% respectively. Five-year relative survival rates for males and females diagnosed with colon cancer in 1997-2001 were both 50%. Ten-year relative survival rates for colon cancers diagnosed in males and females in 1992-1996 were 41% and 44% respectively.
The differences in yearly survival between males and females are not significant, but the differences between survival years for each sex are. The difference between 1-year and 5-year survival rates are greater for both sexes than between 5-year and 10-year survival. While higher numbers of people are likely to survive 1 year, this method of analysis is not effective at depicting true survival. Since 5 and 10-year survival are similar it could be concluded that 5 year survival is a good measure of cure rates.
Figure 6.8: 1-year, 5-year and 10-year relative survival rates in the West Midlands, males and females
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Figures 6.9a and 6.9b show 1-year and 5-year relative survival trends for males and females in the West Midlands. Since the early 1990s, 1-year and 5-year relative survival rates have improved for both males and females. One-year relative survival for males has increased from 65% for cases diagnosed in 1992 to 74% for cases diagnosed in 2005, and for females has increased from 62% for cases diagnosed in 1992 to 71% for cases diagnosed in 2005.
Five-year relative survival for males has increased from 46% for cases diagnosed in 1992 to 51% for cases diagnosed in 2001 and for females has increased from 45% for cases diagnosed in 1992 to 55% for cases diagnosed in 2001. The greatest increases in 5-year relative survival have occurred since 1998; prior to this, the rates in males and females were relatively stable. The increase from 1992 to the end of the time period is statistically significant for 1-year survival in both sexes and for 5-year survival in females. Earlier diagnosis will artificially improve 1-year survival.
Figure 6.9a: Trends in 1-year and 5-year colon cancer relative survival rates in the West Midlands, males
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Figure 6.9b: Trends in 1-year and 5-year colon cancer relative survival rates in the West Midlands, females
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6.3.2 Survival and Deprivation in the West Midlands
Figures 6.10a and 6.10b show how relative survival rates for males and females diagnosed with colon cancer in the West Midlands in 1997-2001 varied with ID2007 deprivation group over the five-year period following their diagnosis. Males in the most deprived group (ID2007 group 1) had the lowest relative survival rates at five years (43%) and females in the most affluent group (ID2007 group 5) the highest relative survival at five years (59%).
Figure 6.10a: West Midlands relative survival by ID2007 deprivation group, males (diagnosed 1997-2001, followed up to 2006)
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Figure 6.10b: West Midlands relative survival by ID2007 deprivation group, females (diagnosed 1997-2001, followed up to 2006)
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Figure 6.10c shows that for males diagnosed with colon cancer in 1997-2001 there was a statistically significant difference between 1-year and 5-year relative survival rates in males in the most deprived groups (ID2007 group 1) and those in the most affluent groups (ID2007 group 5); 1-year and 5-year relative survival being 69% and 43% respectively in the most deprived groups compared with 74% and 53% respectively in the most affluent groups.
Figure 6.10d shows that for females diagnosed with colon cancer in 1997-2001 there was a statistically significant difference between 1-year and 5-year relative survival rates in females in the most deprived group (ID2007 group 1) and those in the most affluent group (ID2007 group 5); 1-year and 5-year relative survival being 66% and 46% respectively in the most deprived group compared with 76% and 59% respectively in the most affluent group.
Figure 6.10c: West Midlands 1-year and 5-year relative survival by ID2007 group, (diagnosed 2001-2005 and 1997-2001 respectively) followed up to end of 2006, males
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Figure 6.10d: West Midlands 1-year and 5-year relative survival by ID2007 group, (diagnosed 2001-2005 and 1997-2001 respectively) followed up to end 2006, females
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6.3.3 1-Year Relative Survival in PCTs
Figures 6.11a and 6.11b show funnel plots of 1-year relative survival rates for males and females in West Midlands PCTs who were diagnosed with colon cancer in 2001-2005. For the West Midlands as a whole the 1-year relative survival rate for males was 69% and the 1-year relative survival rate for females was 67%. The PCT with the highest 1-year relative survival rate for males was Telford & Wrekin PCT at 75%, while the lowest 1-year relative survival rates were in Sandwell PCT and Stoke-on-Trent PCT at 63%. The PCT with the highest 1-year relative survival rate for females was Herefordshire PCT at 71%, while the lowest 1-year relative survival rate was in North Staffordshire PCT at 61%. None of the PCTs had a 1-year relative survival rate in males or females that was significantly higher or lower than the West Midlands average.
6.3.4 5-Year Relative Survival in PCTs
Figures 6.12a and 6.12b show funnel plots of 5-year relative survival rates for males and females in West Midlands PCTs who were diagnosed with colon cancer in 1997-2001. For the West Midlands as a whole the 5-year relative survival rates for males and females were 50%. Herefordshire PCT and Worcestershire PCT had the highest male 5-year relative survival rates at 62% and 57% respectively. At 40%, Sandwell PCT had the lowest 5-year relative survival rate for males and this is significantly lower than the West Midlands average. South Birmingham PCT had the highest 5-year relative survival rate for females at 59% and this is significantly higher than the West Midlands average. Sandwell PCT (38%), Dudley PCT (41%) and Birmingham East & North PCT (42%) all had significantly lower 5-year relative survival rates for females than the West Midlands average.
Figure 6.11a: 1-year relative survival in West Midlands PCTs, males Colon cancers diagnosed in 2001-2005 in males in each PCT
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Figure 6.11b: 1-year relative survival in West Midlands PCTs, males Colon cancers diagnosed in 2001-2005 in females in each PCT
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Figure 6.12a: 5-year relative survival in West Midlands PCTs, males Colon cancers diagnosed in 1997-2001 in males in each PCT
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Figure 6.12b: 5-year relative survival in West Midlands PCTs, females Colon cancers diagnosed in 1997-2001 in females in each PCT
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6.4.1 Key Facts of Colon Cancer incidence in the West Midlands
- In 2006, 2,026 cases of colon cancer were diagnosed in West Midlands residents, and in 2005 there were 957 colon cancer deaths.
- Over 80% of colon cancers in males and females are diagnosed in those aged 60 and over. Age standardised colon cancer incidence and mortality rates in males are 1.3 and 1.6 times higher respectively than those in females.
- Since 1992, incidence rates in males and females have decreased by 13% and 11% respectively and mortality rates have decreased by 23% and 40% respectively.
- In 2006, colon cancer incidence in females was significantly lower in Solihull Care Trust and significantly higher in South Birmingham PCT than the West Midlands average. In 2005, colon cancer mortality in Heart of Birmingham tPCT was significantly lower than the West Midlands average.
- In 2005, mortality/incidence rate ratios in males in Telford & Wrekin PCT and females in Heart of Birmingham tPCT were significantly lower than the West Midlands average. Solihull Care Trust and Stoke on Trent PCT both had significantly higher mortality/incidence rate ratios compared to the West Midlands average.
- 1-year relative survival rates for males and females diagnosed with colon cancer in 2001-2005 were 69% and 67% respectively; 5-year relative survival rates were both 50% and 10-year relative survival rates were 41% and 44% respectively. 1-year and 5-year relative survival rates for males and females have been increased by 45-55% since 1992.
- Although there is no statistically significant relationship between colon cancer incidence and deprivation in the West Midlands, survival is linked to deprivation with males and females in the most deprived groups having worse 1-year and 5-year survival rates.
References:
- National Cancer Information Service, 01/03/2009
- Cancer Research UK; website, Cancer Stats Key Facts 01/03/2009
- National Institute for Clinical Excellence. Improving Outcomes in Colon Cancer: Update Manual
- Data for England taken from the National Cancer Information Service, 01/03/2009
For more information please contact Sarafina
Cotterill
© Public Health, Epidemiology and Biostatistics Unit, School of Health and Population Sciences, University of Birmingham