Causes, symptoms and treatment of bowel cancer: A rising health risk among youngsters

Bowel cancer rates in people aged between 25 and 49 rose in 27 countries and territories. These include non-Western ones, such as Japan, and less wealthy nations, like Turkey (Image: Canva)

Rates of bowel cancer in younger adults have increased in countries around the world, though the trend appears to be most common in high-income nations. According to a study published in the Lancet, the cancer is rising among younger persons aged 25-49 as compared to older adults.

In the paper titled Colorectal cancer incidence trends in younger versus older adults: an analysis of population-based cancer registry data, the researchers found that a number of countries have reported a rise in colon cancer among younger people and a decline in older people. "The findings show that the rising incidence of early-onset colorectal cancer is no longer limited to high-income countries; it now extends to countries and territories in Latin America and the Caribbean (Argentina, Chile, Costa Rica, Ecuador, Martinique, and Puerto Rico), Asia (Israel, Japan, Thailand, and Türkiye), and eastern Europe (Belarus),” according to the paper.

Previous studies have shown that bowel, or colorectal, cancer rates have grown over the past few decades in this age group across several Western countries, including the US, Canada, Australia and the UK. This has led to speculation about whether Western lifestyles, such as diets high in meat or processed food, may be to blame.

Hyuna Sung at the American Cancer Society in Atlanta, Georgia, and her colleagues examined rates of bowel cancer in 50 countries and territories across the world. They collected data on its incidence from 1975 until 2017 using a World Health Organization database, although some countries didn’t start reporting this information until several years after 1975.

The team found that bowel cancer rates in people aged between 25 and 49 rose in 27 countries and territories. These include non-Western ones, such as Japan, and less wealthy nations, like Turkey, raising the possibility that Western lifestyles alone may not be behind the trend.

According to the US-based Mayo Clinic, most people with colon cancer don't have symptoms at first. “When symptoms appear, they'll depend on the cancer's size and where it is in the large intestine,” it added.

• A change in bowel habits, such as more frequent diarrhea or constipation.
• Rectal bleeding or blood in the stool.
• Ongoing discomfort in the belly area, such as cramps, gas or pain.
• A feeling that the bowel doesn't empty all the way during a bowel movement.
• Weakness or tiredness.
• Losing weight without trying.

• Older age: Most people with colon cancer are older than 50. The numbers of people younger than 50 who have colon cancer has been growing, as the study has shown.
• A personal history of colorectal cancer or polyps: Having had colon cancer or colon polyps increases the risk of colon cancer.
• Inflammatory bowel diseases: Conditions that cause pain and swelling of the intestines, called inflammatory bowel diseases, can increase the risk of colon cancer.
• Inherited syndromes that increase colon cancer risk: Some DNA changes that increase the risk of colon cancer run in families.
• Family history of colon cancer: Having a blood relative who has colon cancer increases the risk of getting colon cancer.
• Low-fibre, high-fat diet: Colon cancer might be linked with a typical Western diet that tends to be low in fibre and high in fat and calories. Research in this area has had mixed results.

Doctors recommend that people with an average risk of colon cancer consider starting colon cancer screening around age 45. But people with an increased risk should think about starting screening sooner. If you notice symptoms that last and worry you, it is advisable that you see a doctor.

Making changes in everyday life can reduce the risk of colon cancer.

• Eat a variety of fruits, vegetables and whole grains. Choose a variety of fruits and vegetables so that you get a range of vitamins and nutrients.
• Drink alcohol in moderation, if at all. If you choose to drink alcohol, limit the amount you drink to no more than one drink a day for women and two for men.
• Stop smoking.
• Exercise most days of the week. Try to get at least 30 minutes of exercise on most days. If you've been inactive, start slowly and build up gradually to 30 minutes.
• Maintain a healthy weight. If you are at a healthy weight, work to maintain your weight by combining a healthy diet with daily exercise.

The study also noted limitations in its scope by citing countries like India, where it states that findings derived from the data cannot be seen as a generalisation for the entire country. “Trends in India were based on data from four registries (Barshi, Chennai, Dindigul Ambilikkai, and Mumbai), representing only about 2% of the Indian population. A study of 14 registries, representing 5% of the Indian population, suggested increasing incidence in both age groups until 2014,” it states.