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Bowel cancer awareness

We’re calling for the production and distribution of a leaflet to accompany individual bowel cancer screening notifications.

Bowel cancer is one of the most common cancer types in the UK.  It is also referred to as colorectal cancer.  Bowel cancer has been on rise in the past few decades and there are many theories for this rise. We discuss below some of the latest developments in bowel cancer and its prevention.

Background

Bowel cancer accounts for 11% of all new cancer cases in the UK. Every year, there are almost 42,300 people are diagnosed with bowel cancer in the UK. 1 in 15 men and 1 in 18 women will get bowel cancer during their lifetime. Many risk factors influence bowel cancer risk such as: age, diet, obesity and other lifestyle risks.

But there is also good news. The overall trend for bowel cancer in the UK is decreasing. Although bowel cancer cases were rising between 1971 and 1998, the incidence stabilised until 2012. Since then, we seem to be getting on top of the disease. The rate of new cases began to decrease and fell by 4% in the last decade. However, still around 70 in 100,000 people are diagnosed with bowel cancer in the UK every year.

What are the risk factors?

The main risk factor is age: your risk of getting bowel cancer increases dramatically with age. The majority of people with bowel cancer are typically above 80 years old and the rest above 50. The rate of new cases in people aged below 50 years old is extremely low (Cancer Research UK, 2015-2017). The average age at the time of diagnosis is between 63-72 for colon and rectal cancers.

This may be due to lifestyle risks, especially improved diets that have occurred in the last twenty years. There are many risk factors that are well-known to increase risk of bowel cancer:

  • Diet – especially lack of dietary fibre and red and processed meants
  • Obesity and being overweight
  • Smoking
  • Alcohol
  • Previous cancer conditions
  • Medical conditions (IBS, colitis, chronic inflammation)
  • Radiation
  • Infections
  • Hereditary conditions – especially Lynch syndrome

Some reports in the media may also mislead people into thinking that mobile phones, artificial sweeteners, genetically modified foods or plastic bottles cause bowel cancer. Most of them are not backed up by scientific studies and should be disregarded.

A key risk factor for this disease is lack of dietary fibre. Eating fibre is considered to reduce the risk of bowel cancer by about 28%. 9 out of 10 people in the UK are not eating the recommended amount of fibre every day. Increased consumption of dietary fibre is by far one of the easiest ways of reducing bowel cancer and the research is well documented.  However, many other less impactful suggestions have been mooted.  Refrigerator use was linked to reduced gastric cancer risk in Asia – but now in Western countries.

Similarly, antibiotics were linked to some types of bowel cancer, but were found to prevent others. Aspirin use, calcium and vitamin D are thought to prevent risk of bowel cancer. Chronic inflammation and changes in gut microbiome may also contribute to bowel cancer risk. However, we need to be careful when interpreting bowel cancer risk factors from isolated studies. Many scientific studies need to be repeated across continents to establish a relationship between a risk factor and cancer.

Bowel cancer in young adults

Worryingly, since 2010, the number of new cases among people aged 20-39 years old increased sharply by 5-19%. Since bowel cancer is significantly associated with lifestyle and diet, a key explanation might be the rising levels of obesity and diabetes in younger population. Moreover, young people nowadays tend to be less physically active and have a higher consumption of red meat, increasing their bowel cancer risk.

Source: Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bowel-cancer/incidence#heading-Two, Accessed

Bowel cancer – men and women

Bowel cancer is more common among men than women. Men form almost 56% of all cases, whereas women only 44%. This may be due to different lifestyle habits: women tend to be more interested in healthy diet, exercise and general healthy lifestyle than men, reducing their bowel cancer risk. Perhaps interestingly, women also tend to have a better prognosis than males. This was in past linked to differences in hormonal levels.

Source: Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bowel-cancer/incidence#ref-2,

Bowel cancer deaths

The main factor contributing to decreasing levels of deaths from bowel cancer is bowel cancer screening. UK has a national screening programme for bowel cancer, that helps to reduce bowel cancer incidences and severity thanks to early diagnosis. Additionally, there have been NHS-led campaigns.  For example, campaigns to improve bowel cancer awareness under the ‘Be Clear on Cancer’ label. This may help to improve bowel cancer statistics considerably, by removing the stigma around diagnostic procedures.

If people have a better understanding of colonoscopy, for example, there is less embarrassment associated with it – more people seek early diagnosis and treatment for bowel conditions, in turn helping to reduce bowel cancer incidence and deaths. Probably thanks to screening and awareness, the survival for bowel cancer patients has been steadily improving by almost 60% since 1971.  Net survival in recent years is shown below:

Source: Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bowel-cancer/survival#heading-Two,

Bowel cancer in the UK

Despite the awareness campaign, the age-standardised incidence rate of bowel cancer in the UK is among the highest in the world. Many Western countries have the highest incidence of bowel cancer rates among population, including UK, Germany, Spain, Canada and Australia. Maps as the one shown below, reveals just how much the bowel cancer incidence could be reduced by improved risk modification.

Source: The colorectal cancer epidemic: challenges and opportunities for primary, secondary and tertiary prevention (Brenner and Chen, 2018).

There has long been concern that the survival rate in the UK is lower than in other countries. France, Canada and United States have higher survival rates for colorectal cancer than the UK. Although UK has been improving its survival rate over the last decade.  Diagnostic programmes play a significant role in catching bowel cancer in its earliest stages and improving patients’ prognosis. The awareness around bowel cancer and the risk factors is considered to be lower in the UK, in contrast to, say, the US.

The main difference between UK and US may also be in in clinical recommendations. For example, the US makes greater use of colonoscopies and imaging for people with irritable bowel syndrome (IBS) and this may enable facilitate earlier detection of tumours, since colonoscopy is the primary screening method for early-stage colorectal cancers. Earlier intervention and getting people at risk of bowel cancer to the GP in the UK early would improve outcomes.

Future and prevention of bowel cancer

Prevention and early detection play significant roles in reducing your risk of bowel cancer, and your prognosis if you are diagnosed. Avoiding tobacco, alcohol consumption, eating high fibre diet, improving your diet and exercise habits will all help in reducing your risk of bowel cancer.

And there is further good news in prevention of bowel cancer! There are several trials underway to further reduce your risk. Scientists are trialling low-dose aspirin for preventing bowel cancer.

Taking care of your body and gut will not only improve your bowel cancer risk, but also lifestyle and quality of life.

Submission to National Screening Committee

References

Bowel cancer statistics [WWW Document], 2015. . Cancer Research UK. URL https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bowel-cancer (accessed 5.22.20).

Brenner, H., Chen, C., 2018. The colorectal cancer epidemic: challenges and opportunities for primary, secondary and tertiary prevention. British Journal of Cancer 119, 785–792. https://doi.org/10.1038/s41416-018-0264-x

Center, M.M., Jemal, A., Smith, R.A., Ward, E., 2009. Worldwide Variations in Colorectal Cancer. CA: A Cancer Journal for Clinicians 59, 366–378. https://doi.org/10.3322/caac.20038

Exarchakou, A., Donaldson, L.J., Girardi, F., Coleman, M.P., 2019. Colorectal cancer incidence among young adults in England: Trends by anatomical sub-site and deprivation. PLOS ONE 14, e0225547. https://doi.org/10.1371/journal.pone.0225547

Keum, N., Giovannucci, E., 2019. Global burden of colorectal cancer: emerging trends, risk factors and prevention strategies. Nature Reviews Gastroenterology & Hepatology 16, 713–732. https://doi.org/10.1038/s41575-019-0189-8

Kunzmann, A.T., Coleman, H.G., Huang, W.-Y., Kitahara, C.M., Cantwell, M.M., Berndt, S.I., 2015. Dietary fiber intake and risk of colorectal cancer and incident and recurrent adenoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial12. Am J Clin Nutr 102, 881–890. https://doi.org/10.3945/ajcn.115.113282

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