You might expect a few health problems in your 20s, 30s and 40s – but bowel cancer? Probably not. Although it’s still more common in older people, bowel cancer in younger Australians is on the rise, with the number of cases in under 50s more than doubling between 2000 and 2024.1 Now, for every nine people diagnosed with it, one is younger than 50.2
Experts don’t fully understand why, but they do know what can make you more prone to it. Importantly, learning to recognise bowel cancer symptoms can help with early diagnosis, leading to better outcomes. If you feel like something isn’t quite right, listen to your body.
What exactly is bowel cancer?
Bowel cancer, or colorectal cancer, occurs when cells in the lining of the colon (large intestine) or rectum grow abnormally. Most bowel cancers start as small growths called polyps. These are often harmless but can become cancerous.
Bowel cancer is the forth most commonly diagnosed cancer in Australia.3 The good news is that bowel cancer survival rates have improved dramatically over the past few decades – and are higher in younger than older people.3 Over 90% of cases can be treated successfully when they’re found early.4 That’s why it’s essential to know which symptoms to look out for.
Why are bowel cancer rates increasing in younger people?
Researchers are still figuring out why early-onset bowel cancer (diagnosed before age 50) is becoming more common. Several things are thought to contribute, including:
- dietary changes – diets low in fibre and high in processed foods and red meat are linked to increased risk
- sedentary lifestyles – lack of physical activity is another known risk factor
- rising obesity rates – particularly starting in childhood or adolescence
- changes to the gut microbiome – shifts in gut bacteria may play a role
- smoking and alcohol use – both are linked with bowel cancer risk.
Some studies suggest bowel cancer in younger people may be a bit different, sometimes seeming more aggressive or affecting different parts of the colon to bowel cancer in older adults.5,6
Importantly, younger people tend to be diagnosed later.2,7 This may be because bowel cancer is not usually the first thing that comes to mind when they have bowel symptoms.
Symptoms younger people should watch for
Bowel cancer symptoms can include:
- rectal bleeding or blood in your stool (poo), which may be dark or bright red
- persistent abdominal pain, cramping or bloating
- feeling like your bowel has not emptied properly
- diarrhoea or constipation
- narrow or ribbon-like stools
- unexplained weight loss.
One analysis of 81 studies found the most common symptoms of early-onset bowel cancer were blood in the stool, abdominal pain and changed bowel habits.8
If you do have any of these symptoms, there’s no need to be alarmed. They’re often caused by conditions like haemorrhoids, anal fissures or irritable bowel syndrome (IBS) – which can also be treated successfully. See your GP if you have any symptoms for more than about two weeks.
Bowel cancer risk factors
Risk factors for bowel cancer include:
- inherited conditions such as Lynch syndrome or familial adenomatous polyposis
- bowel diseases such as Crohn’s disease or ulcerative colitis
- obesity
- smoking
- drinking alcohol
- low levels of physical activity
- diets low in fibre and high in processed meats.
What about family history?
Most people who get a bowel cancer diagnosis have no family history. But your risk is higher if a close blood relative (e.g., a parent or sibling) was diagnosed with it.9–11
Talk to your GP if you have any concerns about your bowel cancer risk.
Can people in their 20s and 30s be tested for bowel cancer?
Under Australia’s National Bowel Cancer Screening Program, free bowel cancer screening kits are sent to people aged 50 to 74 every two years. People aged 45 to 49 can also take part in the program but have to get their first kit online or from their GP.
If you’re in your 20s, 30s or early 40s and have bowel cancer symptoms, a strong family history, or other risk factors, speak with your GP. They can assess your individual risk and advise whether further investigation is needed.
When should you see a GP?
Book an appointment as soon as you notice any persistent bowel symptoms. It might feel awkward to talk about poo or your bowel habits, but doctors discuss these things all the time. You could say something like, “I wanted to ask about some changes I’ve noticed,” or “I’ve been having some [symptoms] and thought I should check in.”
If you’re nervous, you could bring a support person to the appointment. You might like to write down your symptoms and questions, so you don't forget anything. And remember, getting medical advice early is better than waiting and worrying. Having that conversation could save your life.
What to expect if you see a doctor about bowel symptoms
Here’s what the process typically looks like.
History taking
Your GP will ask some questions about your symptoms, family history, lifestyle and general health.
Physical examination
They might feel your tummy for any lumps or do a rectal examination (which can be uncomfortable, but is usually not painful).
Investigations
They might organise a stool test or blood tests to help with diagnosis.
Specialist referral
You might be referred to a gastroenterologist or colorectal surgeon for further assessment.
Colonoscopy
In some cases, your doctor might recommend a colonoscopy, which is usually done under sedation in a hospital or clinic. During a colonoscopy, the specialist uses a thin, flexible tube with a camera to look inside the bowel. If they find any polyps, they can often remove them then and there, helping stop cancer from developing.
This might sound a bit intimidating, but most people say the preparation is the hardest part. The procedure itself is usually fast and straightforward.
What could getting checked be worth to you?
Good health is priceless at any age. But when you’re young, you have so much to live for. You might be raising a family, building a career, travelling or giving back to your community. Don’t let bowel cancer get in the way.
Most bowel symptoms are not caused by cancer, but it’s always worth getting checked. You can even get a second opinion if something doesn’t feel right. Remember, no one is too young to get bowel cancer – and early diagnosis saves lives.
Content reviewed by Dr Vu Kwan
Head of Gastroenterology
Norwest Private Hospital.
Reviewed June 2026.
References:
1. Cancer data in Australia, An overview of colorectal cancer in Australia. Australian Institute of Health and Welfare. October 8, 2025. Accessed May 13, 2026. https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-data-commentaries/an-overview-of-colorectal-cancer-in-australia
2. Markey W, Srinath H. The alarming rise of early-onset colorectal cancer. Aust J Gen Pract. 2025;54(6):392-399. doi:10.31128/AJGP-05-24-7281
3. Cancer data in Australia, Cancer incidence by age visualisation. Australian Institute of Health and Welfare. October 8, 2025. Accessed May 13, 2026. https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-incidence-by-age-visualisation
4. Bowel cancer screening. Cancer Council Australia. March 12, 2026. Accessed May 13, 2026. https://www.cancer.org.au/cancer-information/screening-tests-and-treatments/early-detection-and-screening/bowel-cancer-screening
5. Mi X, Zheng P, Wu X. Differential Analysis of Early-Onset and Late-Onset Colorectal Cancer Based on Multidimensional Evidence Integration: A Review. Cancer Control. 2025;32:10732748251363337. doi:10.1177/10732748251363337
6. Tashkandi E. The Rise of Early-Onset Colorectal Cancer: Clinical Characteristics and Outcomes in a Young Patient Population. Cancer Manag Res. 2025;Volume 17:2417-2427. doi:10.2147/CMAR.S554044
7. Lamprell K, Pulido DF, Arnolda G, et al. People with early-onset colorectal cancer describe primary care barriers to timely diagnosis: a mixed-methods study of web-based patient reports in the United Kingdom, Australia and New Zealand. BMC Prim Care. 2023;24(1):12. doi:10.1186/s12875-023-01967-0
8. Demb J, Kolb JM, Dounel J, et al. Red Flag Signs and Symptoms for Patients With Early-Onset Colorectal Cancer: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2024;7(5):e2413157. doi:10.1001/jamanetworkopen.2024.13157
9. Far PM, Alshahrani A, Yaghoobi M. Quantitative risk of positive family history in developing colorectal cancer: A meta-analysis. World J Gastroenterol. 2019;25(30):4278-4291. doi:10.3748/wjg.v25.i30.4278
10. Keivanlou MH, Amini-Salehi E, Joukar F, et al. Family history of cancer as a potential risk factor for colorectal cancer in EMRO countries: a systematic review and meta-analysis. Sci Rep. 2023;13(1):17457. doi:10.1038/s41598-023-44487-8
11. Maria-Alexia P, Cristina R, Andreea-Ramona T, Octavian A, Viorica R. Familial colorectal cancer: risk factors, screening strategies and personalized medicine. Cancer Genet. 2026;302-303:166-175. doi:10.1016/j.cancergen.2026.02.008
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