Bowel cancer: What to do and how to recognise the symptoms
Be aware of the early warning signs and see your GP if you are concerned
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. Photograph: iStock
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 per cent of us will develop it. The good news is that colorectal cancer deaths have decreased substantially 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 per cent of cases occur in people over 40, and 85 per cent 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. More than 2,700 people are diagnosed with bowel cancer in Ireland every year. It is also the second most common cause of cancer death in Ireland.
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 per cent 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 the 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 risk 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 per cent 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. Red meat (pork, beef and lamb) is a good source of protein, but 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 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. In a recent breakthrough, it is hoped “genetic signatures” found in bowel cancer cells will soon help identify the best treatments for those with the condition, according to international research led by Queen’s University Belfast.
Anyone at greater-than-average risk of bowel cancer (positive family history, ulcerative colitis or Crohn’s disease) should be advised about whether and when to have screening with colonoscopy.
Otherwise, BowelScreen, the national bowel screening programme, will send people in the 60-69 year age group a letter asking them to take part in the bowel-screening programme. This process has begun, but may take up to three years. Men and women who are called for screening and who are willing to take part in the screening programme are sent a home test kit called FIT (Faecal Immunochemical Test) in the post. This test is carried out by the person in their own home. The person completes the test and sends samples by freepost to a laboratory. About five in 100 people will receive an abnormal result and will need an additional test. They will be referred to the hospital for a screening colonoscopy to determine any abnormality in the bowel. The plan is to, in the future, expand the programme until the full 55-74 age group is reached.