Bowel Cancer in Australia – The Facts and Insights

Key Statistics

Incidence - an estimated 15,542 Australians were diagnosed with colorectal (bowel) cancer in 2024, accounting for 9.2% of all new cancer cases.
Mortality - approximately 5,239 Australians died from bowel cancer in 2023, representing 9.9% of all cancer-related deaths.
Survival rate - the five-year relative survival rate for bowel cancer is 71% (2016–2020 data).
Lifetime risk - about 1 in 13 Australians will be diagnosed with bowel cancer by the age of 85.
Early detection - over 90% of bowel cancers can be successfully treated if detected early.

Understanding Bowel Cancer

Bowel cancer, also known as colorectal cancer (CRC), develops when abnormal cells in the lining of the bowel grow uncontrollably. These growths, called polyps or adenomas, are typically benign initially, but can become cancerous over time. Regular screening is crucial, as polyps can exist for years without causing symptoms before turning malignant.

Risk Factors

Several factors can increase the risk of developing bowel cancer:

Age - 50 years or older.
Lifestyle - a diet high in red and processed meats, low in fibre, excessive alcohol consumption, smoking and lack of physical activity.
Medical history - inflammatory bowel diseases like Crohn's disease or ulcerative colitis, or a history of non-cancerous bowel tumours.
Family history - a first-degree relative with bowel cancer doubles your risk; two first-degree relatives quadruples your risk. However, over 80% of cases occur in individuals without a family history.

Symptoms

Bowel cancer can develop without noticeable symptoms, especially in the early stages. It’s important to visit your GP without delay if you experience one or more of the following:

Rectal bleeding or blood in the stool.
Persistent changes in bowel habits such as diarrhea, constipation or a feeling of incomplete evacuation.
Unexplained fatigue or weakness, which may indicate anaemia.
Abdominal pain or cramping.

Prevention

Reducing your risk of bowel cancer involves lifestyle modifications and preventive measures including:

Healthy diet - increase intake of fruits, vegetables and whole grains while reducing fried foods, red and processed meats.
Regular exercise - engage in physical activity most days of the week.
Limit alcohol and avoid smoking - both are linked to increased cancer risk.
Aspirin use - Australian guidelines recommend adults aged 50–70 years consider taking low-dose aspirin (100–300 mg daily) for at least 2.5 years to reduce the risk of colorectal cancer, unless contraindicated.
Regular screening - participate in recommended screening programs to detect early signs of cancer.

National Bowel Cancer Screening Program (NBCSP)

The NBCSP offers free screening to Australians aged 50 to 74, distributing faecal occult blood test (FOBT) kits every two years. Early detection through this program significantly improves treatment outcomes.

Participation rate - only 40% of the six million people invited between January 2021 and December 2022 completed the screening, indicating a need for increased awareness and participation.
Positive results - among participants, 6% had a positive FOBT result requiring further assessment.
Impact - the program has contributed to reducing morbidity and mortality from bowel cancer in Australia.

Treatment

Treatment for bowel cancer depends on the stage and location of the cancer but often includes:

Surgery – to remove cancerous sections of the bowel.
Chemotherapy and radiation therapy - to eliminate remaining cancer cells and reduce recurrence risk.

Early-stage cancers have a higher chance of successful treatment and recovery.

Role of General Practitioners (GPs)

GPs are pivotal in the early detection and prevention of bowel cancer through:

Patient education - inform patients about the importance of screening and lifestyle modifications.
Screening encouragement - encourage eligible patients to participate in the NBCSP.
Risk assessment - identify patients with higher risk due to family history or medical conditions and recommend appropriate surveillance.
Symptom evaluation - promptly investigate any reported symptoms indicative of bowel cancer.

Staying informed and proactive in screening and lifestyle choices can significantly reduce the risk and impact of bowel cancer.

References - Cancer Australia; NBCSP