Key facts
- Colorectal cancer is the third most common cancer worldwide, accounting for approximately 10% of all cancer cases.
- It is the second leading cause of cancer-related deaths worldwide.
- It predominantly affects individuals aged 50 and above, though there is a rising burden among adults 30–50 years old in some settings.
- 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, a sedentary lifestyle, obesity, smoking, and alcohol consumption.
- The incidence and impact of colorectal cancer can be significantly reduced by adopting a healthy lifestyle, avoiding risk factors, and monitoring symptoms to enable timely diagnosis and treatment.
Overview
Colorectal cancer affects the colon (large intestine) or rectum and is one of the most common cancers worldwide. It can cause severe illness and premature death, particularly when diagnosed at advanced stages. The risk of colorectal cancer increases with age, with most cases occurring in people over 50 years, although several countries are reporting rising incidence among younger adults(1). Common symptoms include diarrhoea or constipation, blood in the stool, abdominal pain, unexplained weight loss, fatigue and low iron levels, but many people have no symptoms in the early stages.
In 2022, an estimated 1.9 million new cases of colorectal cancer and more than 900 000 deaths occurred worldwide, making it the second leading cause of cancer-related death. Incidence rates were highest in Europe and in Australia and New Zealand, while mortality rates were highest in Eastern Europe. Incidence and mortality have declined in several high-income countries, mainly due to earlier detection. Prognosis strongly depends on the stage at diagnosis, with substantially higher survival for cancers detected early.
Risk factors
Factors that increase the risk of colorectal cancer include:
- lifestyle factors: diets high in processed and red meat and low in fruits and vegetables, physical inactivity, overweight and obesity, tobacco use and alcohol consumption;
- family history and genetics: a family history of colorectal cancer or inherited conditions such as Lynch syndrome or familial adenomatous polyposis (FAP);
- personal history: previous colorectal cancer or certain types of polyps; and
- age: risk increases markedly after age 50 though can occur at a younger age.
Prevention
Colorectal cancer can be prevented through a healthy lifestyle and early detection(2). Key prevention measures include:
- eating a healthy diet rich in fruits and vegetables;
- not using tobacco;
- keeping an active lifestyle;
- maintaining a healthy body weight;
- limiting alcohol consumption;
- avoiding exposure to environmental risk factors.
Symptoms
Colorectal cancer often has no or mild symptoms in the early stages. When symptoms occur, they may include:
- changes in bowel habits such as diarrhoea, constipation, or narrowing of the stool;
- blood in the stool (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;
- persistent fatigue; and
- iron deficiency anaemia due to chronic bleeding.
People who suspect they may have colorectal cancer should speak to their health-care provider right away.
Early detection
Early diagnosis programmes can reduce delays in receiving care after symptom onset. Treatments are more likely to cure the disease in the early stages. In settings with organized screening programmes, regular screening is the most effective way to detect colorectal cancer early and prevent the disease through the identification and removal of precancerous lesions. Screening has been shown to reduce both incidence and mortality.
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.
People with a family history of colorectal cancer or inherited cancer syndromes may benefit from genetic counselling and tailored screening strategies.
Treatment
Treatment depends on the stage of disease, tumour characteristics and the person’s overall health.
Options include:
- surgery
- radiotherapy (radiation)
- chemotherapy
- targeted therapy
- immunotherapy.
Multidisciplinary teams are essential for optimal care, and supportive care plays a key role in managing symptoms, relieving pain and improving quality of life for patients and their families.
Early stage disease
Early-stage colorectal cancer is primarily treated with surgical removal of the tumour and nearby lymph nodes. Depending on tumour location, this may involve colectomy or proctectomy, sometimes with temporary or permanent stoma formation. Adjuvant chemotherapy may be recommended for patients at higher risk of recurrence, and neoadjuvant therapy or radiotherapy is commonly used for rectal cancer to reduce tumour size. Regular follow-up and surveillance after treatment are essential.
Advanced disease
For metastatic colorectal cancer, systemic therapy is the main treatment approach. Chemotherapy is often used first-line, alone or in combination with targeted therapies for patients with specific molecular profiles. Immunotherapy may benefit patients with tumours that are microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR). Surgery or local treatments such as ablation or radiotherapy may be used to manage selected metastases or relieve symptoms.
Clinical trials
Clinical trials offer opportunities to access novel treatments or experimental therapies. Participation in clinical trials helps advance medical knowledge and potentially offers new treatment options.
WHO response
The WHO is actively involved in addressing the global burden of colorectal cancer and implementing strategies to reduce its impact. WHO's approach involves raising awareness, cancer prevention and control, early detection, strengthening health systems, capacity building, research and surveillance, as well as collaboration and partnerships. These comprehensive efforts contribute to reducing the burden of colorectal cancer by promoting prevention, early detection, equitable access to quality care, and improving overall cancer control globally.
References
(1) Ferlay J, Ervik M, Lam F, Colombet M, Mery L, Piñeros M, et al. Global Cancer Observatory: Cancer Today. Lyon: International Agency for Research on Cancer; 2020 (https://gco.iarc.fr/today, accessed February 2021).
(2) Fink H, Langselius O, Vignat J, Rumgay H, Rehm J, et at. Global and regional cancer burden attributable to modifiable risk factors to guide prevention. Nat Medicine. 3 February 2026.