Colorectal cancer is the third leading cause of cancer deaths in the developed world – but mortality has decreased by 30% in the past 20 years
Be aware of early warning signs (blood in stool, frequent/loose stools, abdominal pain/bloating after eating, or weight loss) and see your GP if you are concerned. But don’t panic. Colorectal (bowel) cancer is the third leading cause of deaths from cancer in the developed world, but only 5.4% of us will develop it. The good news is that colorectal cancer deaths have decreased by 30% in the past 20 years – partly because of screening, earlier detection and better treatment.
Especially if you’re over 60
Age is the greatest risk factor: 99% of cases occur in people over 40 and 85% in people over 60. Most people diagnosed are in their 70s. Unfortunately, it’s often older people who are most reluctant to report abnormal bowel symptoms.
Know your family history
It’s important to know your family’s medical history, with the proviso that most people who get bowel cancer don’t have any particular inherited tendency and their children won’t be at increased risk compared with the general population. But in 5-6% of cases, there is a genetic predisposition, and there are likely to have been other cases in the family. If you have a single first-degree relative with bowel cancer, your risk is two to three times higher than average (or higher if that relative was under 45 years old when they developed cancer). If you have two affected first-degree relatives, your risk may be as high as four times the average. The most common inherited conditions that cause bowel cancer are familial adenomatous polyposis and Lynch syndrome.
Stay slim and active
Obesity increases the risk of developing and dying from bowel cancer by 1.5 times. The association is stronger for men than women. If you are obese, try to stay active; physical activity seems to offset some of the increased risks of being overweight. Most studies suggest that eating lots of fibre reduces the risk, but that may be partly because people who are a healthy weight tend to have a high-fibre diet.
Easy on the meat
Processed, smoked and cured meats can increase the risk of bowel cancer because they contain chemicals called nitrosamines. People who eat the most processed meat have about a 17% higher risk of developing bowel cancer, compared with those who eat the least. That means 56 out of 1,000 people may get bowel cancer among people who never eat processed meat, 61 out of 1,000 average meat eaters and 66 out of 1,000 among those who eat the most processed meat. The NHS advice is that red meat (pork, beef and lamb) is a good source of protein, but that eating more than 90g a day is associated with an increased risk of bowel cancer. One lamb chop is 70g, so if you have a couple of chops, you may want to give the red meat a miss the following day.
An aspirin a day?
Taking a low dose (75mg) of aspirin a day for five years may reduce your risk of bowel cancer, but the risk of gastric bleeding is thought to outweigh the potential benefits. The jury is still out on this one. Likewise, there is no robust evidence yet that statins or hormone replacement therapy prevent bowel cancer.
Anyone at greater than average risk of bowel cancer (positive family history, ulcerative colitis or Crohn’s disease) will be advised about whether and when to have screening with colonoscopy. For the rest of us, the national screening programme in England kicks in aged 55, with a one-off bowel scope screening test in some areas (this is the test Andrew Lansley – the former health secretary who now has bowel cancer – wants to be rolled out more widely, as it’s currently only available to 50% of eligible people). Those between 60 and 74 years old get sent a home-testing kit once every two years to detect blood in the stool with further investigation if positive. If you want to carry on doing the home test every two years over the age of 75, you can phone the bowel cancer screening helpline on 0800 707 60 60 to request a kit. In Scotland, the programme starts at 50 and broadcaster George Alagiah, who also has bowel cancer, is campaigning for the same service to be provided across the UK.
Credit: Ann Robinson for The Guardian, 16 April 2018.