Colorectal Cancer in South Africa: Why Awareness and Early Detection Matter

Colorectal cancer, also known as colon or rectal cancer, is one of the most important cancers South Africans should be talking about more openly. It affects the large intestine or rectum and often develops slowly from small growths called polyps. The challenge is that colorectal cancer can grow quietly for years before symptoms become obvious. By the time many patients seek medical help, the disease may already be advanced.

In South Africa, colorectal cancer is no longer a rare or distant concern. Current cancer data shows that it is one of the most frequently diagnosed cancers in the country. According to recent national cancer statistics, colorectal cancer is among the leading invasive cancers in both men and women. International cancer estimates for South Africa also show thousands of new cases every year, with a significant number of deaths linked to the disease.

This makes colorectal cancer a serious public-health issue — not because it is always unavoidable, but because many cases can be detected earlier, treated more effectively, or even prevented if risk factors are addressed and warning signs are taken seriously.

How common is colorectal cancer in South Africa?

Colorectal cancer is consistently listed among South Africa’s most common cancers. Recent data places it within the top five invasive cancers in both men and women. This is important because colorectal cancer is sometimes wrongly viewed as a disease that mainly affects people in high-income countries or older populations only.

While age remains a major risk factor, South African cancer organisations have also noted concern about younger people being diagnosed. This does not mean every young person is at high risk, but it does mean that persistent bowel symptoms should never be ignored simply because someone is “too young” to have cancer.

The burden of colorectal cancer in South Africa is also concerning because mortality remains high. In simple terms, although South Africa’s incidence may be lower than some high-income countries, too many patients are still dying from the disease. One of the main reasons is late detection.

Why is colorectal cancer increasing?

There is no single reason why colorectal cancer occurs. It is usually the result of a combination of lifestyle, genetic, environmental and healthcare-access factors. However, several patterns help explain why colorectal cancer is becoming more visible in South Africa.

1. Lifestyle and diet changes

Modern diets have changed significantly over the past few decades. Many people are eating more processed foods, refined carbohydrates, red meat and processed meats, while eating fewer fibre-rich foods such as vegetables, fruit, legumes and whole grains.

A low-fibre diet may affect bowel health because fibre helps food move through the digestive system and supports a healthier gut environment. Diets high in processed meat and red meat have been linked to an increased risk of colorectal cancer. This does not mean that one meal causes cancer, but long-term dietary patterns matter.

2. Obesity and physical inactivity

South Africa has high levels of obesity and sedentary behaviour. Many adults spend long hours sitting at work, commuting, or using screens, with limited time for regular physical activity.

Physical inactivity and excess body weight are recognised risk factors for colorectal cancer. Regular movement helps support healthy digestion, weight control, insulin regulation and overall metabolic health. When inactivity is combined with poor diet, smoking or alcohol use, the risk profile becomes more concerning.

3. Smoking and alcohol use

Smoking is often associated mainly with lung cancer, but it is also linked to several other cancers, including colorectal cancer. Alcohol use is another recognised risk factor. The risk tends to increase with heavier and more regular consumption.

For many South Africans, cancer prevention conversations focus on one organ or one disease at a time. In reality, the same lifestyle factors often influence multiple diseases, including cancer, diabetes, high blood pressure and heart disease.

4. Family history and inherited risk

Some colorectal cancers are linked to inherited genetic conditions such as Lynch syndrome or familial adenomatous polyposis. These conditions can cause cancer to develop at a younger age and may affect several members of the same family.

South African researchers have highlighted that inherited colorectal cancer may be an important issue locally. This makes family history especially important. A person should tell their doctor if a close relative has had colorectal cancer, especially if that relative was diagnosed at a younger age.

Families often do not talk openly about bowel disease, cancer, or surgery involving the colon. This silence can prevent relatives from understanding their own risk and seeking earlier screening.

5. Late diagnosis and limited screening

One of the most important reasons colorectal cancer remains dangerous is that early disease may cause no symptoms. When symptoms do appear, people may delay seeking help because they feel embarrassed, assume it is piles, blame diet, or hope the problem will go away.

South Africa does not yet have the same level of broad, population-based colorectal cancer screening found in some high-income countries. Access to colonoscopy and specialist care can also vary depending on whether a person is in the public or private sector, where they live, and how quickly they can move through the healthcare system.

Research from South African colorectal cancer cohorts has shown that many patients present with advanced disease. This is the key issue: stage at diagnosis is one of the strongest predictors of survival. The earlier colorectal cancer is found, the better the chance of effective treatment.

Symptoms South Africans should not ignore

Colorectal cancer can be silent in the early stages, but warning signs may include:

• Blood in the stool or bleeding from the rectum
• A change in bowel habits that does not settle
• Ongoing constipation or diarrhea
• Unexplained weight loss
• Persistent abdominal pain, cramps or bloating
• Unexplained tiredness or iron-deficiency anemia
• A feeling that the bowel does not empty properly

These symptoms do not always mean cancer. They can be caused by many other conditions. However, they should be checked, especially if they persist, worsen, or occur in someone with a family history of colorectal cancer.

What can reduce the risk?

Not every case of colorectal cancer can be prevented, but risk can be reduced. Practical prevention steps include eating more fibre-rich foods, limiting processed meats, maintaining a healthy weight, exercising regularly, avoiding smoking, limiting alcohol and taking persistent bowel symptoms seriously.

People with a family history of colorectal cancer should speak to a healthcare professional about whether they need earlier or more frequent screening. For some people, screening may involve stool tests, colonoscopy or referral to a specialist.

The message: do not wait for severe symptoms

Colorectal cancer is treatable, especially when found early. The problem is that too many people wait until symptoms become severe. Awareness can save lives, but only if it leads to action.

South Africans need to become more comfortable talking about bowel health. Blood in the stool, unexplained changes in bowel habits and persistent digestive symptoms should not be dismissed or hidden out of embarrassment.

Early detection gives patients more options, better outcomes and a greater chance of recovery. When it comes to colorectal cancer, the most important message is simple: listen to your body, know your family history, and seek medical advice early.

References

1. International Agency for Research on Cancer / Global Cancer Observatory — South Africa Fact Sheet, GLOBOCAN 2022. View source
2. CANSA — South African Cancer Statistics / National Cancer Registry 2024 summary. View source
3. World Health Organization — Colorectal Cancer Fact Sheet. View source
4. South African Health Review — Reducing colorectal cancer mortality in South Africa: experiences and progress from the South African National Cancer Prevention Services. View source
5. Katsidzira et al. — Investigation on the hereditary basis of colorectal cancers in an African population with frequent early onset cases. View source