Colorectal Cancer – Key Facts
- Colorectal cancer is the third most common cancer worldwide, accounting for approximately 10% of all cancer cases and is the second leading cause of cancer-related deaths worldwide.
- It predominantly affects older individuals, with the majority of cases occurring in people aged 50 and above.
- Several lifestyle factors contribute to the development of colorectal cancer such as a high intake of processed meats and low intake of fruits and vegetables, sedentary lifestyle, obesity, smoking, and excessive alcohol consumption.
- Colorectal cancer is often diagnosed at advanced stages when treatment options are limited.
- The incidence and impact of colorectal cancer can be significantly reduced by implementing primary prevention strategies such as adopting a healthy lifestyle, avoiding risk factors, and practicing early detection through screening.
Overview
Colorectal cancer is a type of cancer that affects the colon (large intestine) or rectum. It is one of the most common types of cancer worldwide. It can cause severe harm and death.
The risk of colorectal cancer increases with age. Most cases affect people over 50 years old.
Common symptoms include diarrhoea, constipation, blood in the stool, abdominal pain, unexplained weight loss, fatigue, and low iron levels.
Many people will not have symptoms in the early stages of the disease.
The risk of colorectal cancer can be reduced by eating a healthy diet, staying physically active, not smoking tobacco and limiting alcohol. Regular screenings are crucial for early detection.
Colon cancer is the second leading cause of cancer-related deaths worldwide. In 2020, more than 1.9 million new cases of colorectal cancer and more than 930 000 deaths due to colorectal cancer were estimated to have occurred worldwide. Large geographical variations in incidence and mortality rates were observed. The incidence rates were highest in Europe and Australia and New Zealand, and the mortality rates were highest in Eastern Europe. By 2040 the burden of colorectal cancer will increase to 3.2 million new cases per year (an increase of 63%) and 1.6 million deaths per year (an increase of 73%).
Incidence rates of colorectal cancer have been decreasing in high-income countries, largely as a result of effective screening programmes. The prognosis for colorectal cancer varies depending on the stage at diagnosis. Early-stage cancers have higher survival rates than advanced-stage cancers. Timely diagnosis, appropriate treatment, and regular follow-up care are important for improving survival rates and quality of life.
Risk Factors
Factors that may increase the risk of developing colorectal cancer include:
- age: the risk of developing colorectal cancer increases with age, with most cases occurring in individuals over 50 years old;
- family history: a family history of colorectal cancer or certain genetic conditions, such as Lynch syndrome and familial adenomatous polyposis (FAP), can increase the risk;
- personal history: individuals who have had colorectal cancer before or certain types of polyps are at a higher risk; and
- lifestyle factors: unhealthy lifestyle choices, such as a diet high in processed meats and low in fruits and vegetables, sedentary behaviour, obesity, smoking and excessive alcohol consumption, can increase the risk.
Symptoms
Colorectal cancer often has no symptoms in the early stages. Regular screenings are important to catch the disease early and begin treatment.
Common symptoms include:
- changes in bowel habits such as diarrhoea, constipation, or narrowing of the stool
- blood in the stool (rectal bleeding), either bright red or dark and tar-like
- abdominal cramps, pain or bloating that won’t go away
- unexplained weight loss that is sudden and losing weight without trying
- feeling constantly tired and lacking energy, even with enough rest
- iron deficiency anaemia due to chronic bleeding, causing fatigue, weakness and paleness.
Prevention
Lifestyle changes and regular screening can help prevent colorectal cancer.
Lifestyle changes to help prevent colorectal cancer include:
- eating a healthy diet rich in fruits and vegetables
- not smoking tobacco
- keeping an active lifestyle
- limiting alcohol consumption
- avoiding exposure to environmental risk factors.
People who suspect they may have colorectal cancer should speak to their healthcare provider right away.
Regular screening for colorectal cancer (secondary prevention) is the best way to catch the disease early.
Treatments are more likely to cure the disease in the early stages.
Studies have shown that screening can reduce both the incidence and mortality of colorectal cancer through early detection and removal of precancerous growths.
Stool-based tests are non-invasive screening methods used to detect the presence of colorectal cancer or precancerous polyps in the stool. The common type of stool-based tests is the fecal occult blood test (FOBT). FOBT detects hidden blood in the stool, which can be an indicator of colorectal cancer or polyps. It involves collecting a small sample of stool and sending it to a laboratory for analysis. If blood or abnormal findings are detected in the stool, further diagnostic procedures, such as colonoscopy, are usually recommended to confirm the presence of colorectal cancer or polyps.
Stool-based tests are convenient, non-invasive, and can be effective in detecting colorectal cancer at early stages or identifying precancerous polyps.
Individuals with a family history of colorectal cancer or certain genetic conditions may benefit from genetic counselling and genetic testing to assess their risk and determine appropriate screening measures.
Diagnosis
Diagnostic methods for colorectal cancer include physical examination, imaging (such as abdominal ultrasound, computed tomography scans, and magnetic resonance imaging), examination of the inside of the colon using colonoscopy or sigmoidoscopy, taking a sample of tissue (biopsy) for histopathology examination, and molecular testing to identify specific genetic mutations or biomarkers to guide the best treatment option.
Treatment and care
Treatments for colorectal cancer are based on the type and progression of the cancer and the person’s medical history. Early detection of colorectal cancer can lead to better treatments and outcomes.
Treatments include:
- surgery
- radiotherapy (radiation)
- chemotherapy
- targeted therapy
- immunotherapy.
Surgery is often used in the early stages of cancer if the tumour has not spread to other areas of the body. Chemotherapy and radiation therapy can help shrink the tumour.
Doctors from several disciplines often work together to provide treatment and care of people with colorectal cancer.
Supportive care is important for people with colorectal cancer. It aims to manage symptoms, provide pain relief, and give emotional support. It can help to increase quality of life for people with colorectal cancer and their families.
