For many years, doctors primarily associated bowel cancer with older adults. While age remains an important risk factor, doctors and researchers are now seeing a concerning change: more adults under 50 are receiving a bowel cancer diagnosis.
Bowel cancer still affects older adults more often than younger people. However, rising rates among younger adults deserve attention because people may mistake early symptoms for more common problems such as haemorrhoids or dietary changes.For patients, the practical message is simple: persistent or unexplained bowel symptoms deserve medical attention, whatever your age.
At Capstone Medical Centre Southbank, your GP can assess symptoms, review your personal and family history, and advise whether further investigation is appropriate.
What Is Bowel Cancer?
Bowel cancer, also called colorectal cancer, develops in the colon or rectum.
Many bowel cancers begin as small growths in the lining of the bowel called polyps. Most polyps are not cancerous, but some types can gradually develop into cancer over a number of years.
Bowel cancer can sometimes develop without causing obvious symptoms, particularly in its early stages. This is one reason screening is important for people who are eligible.
When symptoms are present, they vary considerably between individuals. A change in bowel habit, for example, is very common and usually has a cause other than cancer. What matters clinically is whether the change is new, persistent, unexplained or associated with other concerning symptoms.
Why Is Bowel Cancer Increasing in Younger Adults?
Bowel cancer diagnosed before the age of 50 is often referred to as early-onset colorectal cancer.
Studies from several countries, including Australia, have reported increasing rates of early-onset bowel cancer over recent decades.
Exactly why this is happening is not yet fully understood.
Researchers are examining a range of possible contributors, including changes in diet, body weight, physical activity, metabolic health and environmental exposures. There is also growing scientific interest in whether changes in the gut microbiome may play a role.
Established factors associated with bowel cancer risk include:
- A family history of bowel cancer
- Certain inherited genetic conditions
- Inflammatory bowel disease, including Crohn’s disease and ulcerative colitis
- Being above a healthy weight
- Physical inactivity
- Smoking
- Alcohol consumption
- Diets high in red and processed meats
- Low dietary fibre intake
It is important to put these factors into context. Having one or more risk factors does not mean that a person will develop bowel cancer, and some people diagnosed with bowel cancer have no obvious risk factors.
What Symptoms Should Younger Adults Look Out For?
Bowel symptoms are common and, in most cases, are not caused by cancer.
However, symptoms that persist, recur or represent a significant change from what is normal for you should be discussed with a healthcare professional.
Symptoms that may require assessment include:
- Blood in the stool or rectal bleeding
- A persistent change in bowel habits
- Ongoing diarrhoea or constipation
- Abdominal pain or discomfort that does not settle
- Persistent bloating
- Unexplained weight loss
- Unusual or persistent tiredness
- Iron deficiency anaemia
- A persistent feeling that the bowel has not completely emptied
A single episode of a bowel symptom may have a straightforward explanation. The pattern over time, associated symptoms and your individual risk factors help your doctor determine whether further investigation is needed.
When Should You See a GP?
It is worth making an appointment if you notice a new bowel symptom that persists or keeps returning, particularly if you have rectal bleeding, unexplained weight loss, ongoing abdominal symptoms or significant fatigue.
Your GP will usually start by asking about the symptoms in detail. This may include how long they have been present, whether your bowel habits have changed, whether you have noticed blood, and whether there have been changes in your weight or general health.
Your doctor may also ask about medications, previous bowel conditions and your family history.
Depending on the clinical findings, further assessment may include examination, blood tests or referral for additional investigations such as colonoscopy.
Importantly, bowel screening is intended for people who do not have symptoms. If you have symptoms that could indicate a bowel problem, speak with your GP rather than waiting for or relying on a routine screening test.
Does Family History Matter?
Yes, although the degree of risk depends on which relatives have been affected, how many family members have had bowel cancer and the age at which they were diagnosed.
Tell your GP if:
- A parent, sibling or child has had bowel cancer
- A close relative developed bowel cancer at a relatively young age
- Several relatives on the same side of your family have had bowel cancer
- There is a family history of significant bowel polyps
- Your family has a known inherited cancer syndrome
Inherited conditions such as Lynch syndrome and familial adenomatous polyposis (FAP) can substantially increase bowel cancer risk.
People with a significant family history may need screening or surveillance at a younger age than the general population. Your GP can help assess your family history and determine whether specialist advice is appropriate.
Bowel Cancer Screening in Australia
Australia’s National Bowel Cancer Screening Program provides free bowel screening for eligible people aged 45 to 74.
The program uses an immunochemical faecal occult blood test, usually called an iFOBT. Participants complete the test at home and search for very small amounts of blood in stool that may not be visible.
Under the current program:
- People aged 45–49 can request their first free screening kit.
- People aged 50–74 are generally sent a free kit every two years.
- Eligible people aged 45–74 can also speak with a healthcare professional about accessing a kit.
A positive result does not mean that you have bowel cancer. The presence of blood requires clinicians to perform further investigations to determine the cause.
For people without symptoms, regular screening can help identify bowel cancer at an earlier stage and may also lead to the detection of precancerous polyps.
Can You Reduce Your Risk of Bowel Cancer?
There is no way to completely prevent bowel cancer. Some important risk factors, including age, genetics and family history, cannot be changed.
However, there are practical steps that support bowel health and are associated with a lower risk of colorectal cancer.
Eat Enough Fibre
Wholegrains, legumes, vegetables and fruit are useful sources of dietary fibre. Increasing fibre intake, especially from wholegrains, lowers the risk of bowel cancer.
Stay Physically Active
People who exercise regularly lower their risk of bowel cancer and support cardiovascular and metabolic health.
Maintain a Healthy Weight
Excess body weight increases the risk of several cancers, including bowel cancer.
Limit Processed Meat and Moderate Red Meat Intake
Studies show that processed meats increase the risk of colorectal cancer. Consuming red meat at high levels raises the risk of colorectal cancer.
Avoid Smoking
Smokers face higher risks for several cancers and for colorectal cancer.
Limit Alcohol
Alcohol consumption increases the risk of bowel cancer. The risk generally increases as alcohol intake increases.
These measures reduce risk at a population level, but they do not replace screening or medical assessment when symptoms are present.
Bowel Health Assessment in Southbank
If you have noticed a persistent change in your bowel habits, rectal bleeding or another unexplained gastrointestinal symptom, a GP is an appropriate first point of contact.
At Capstone Medical Centre Southbank, your GP takes history, assesses symptoms, and discusses whether you need testing or a referral.
Many bowel symptoms arise from conditions other than cancer. Seeking medical advice is not about assuming the worst; it is about establishing the cause of a persistent symptom rather than leaving it unexplained.
If you have a strong family history of bowel cancer, it is also worth discussing this with your doctor even if you currently feel well. Your family history may affect when screening or additional surveillance should begin.
Why Early Assessment Matters
Detecting bowel cancer early allows clinicians to offer more treatment options and achieve better outcomes.
For younger adults in particular, awareness matters because bowel cancer may not immediately be considered when symptoms first appear.
There is no need to become alarmed by every temporary change in digestion. However, ongoing rectal bleeding, a persistent change in bowel habits or other unexplained symptoms should not be ignored simply because you are young.
If something has changed and is not returning to normal, speak with your GP.
Frequently Asked Questions
Can you get bowel cancer in your 20s or 30s?
Yes, although it is much less common than in older adults. Bowel cancer can occur at almost any adult age, and rates among younger adults have been increasing. Persistent symptoms should therefore be assessed on their clinical features rather than dismissed because of age alone.
Does blood in the stool mean I have bowel cancer?
No. Rectal bleeding has several possible causes, and many are not cancerous. Haemorrhoids are one common example. However, you should speak with your GP about new, recurrent or unexplained bleeding, particularly if it occurs with changes in bowel habits, abdominal symptoms, weight loss or anaemia.
What is usually the first sign of bowel cancer?
There is no single first symptom. Some people notice rectal bleeding or a change in bowel habits, while others develop abdominal symptoms, iron deficiency anaemia or fatigue. Some people have no noticeable symptoms during the early stages.
Should I do a bowel screening test if I have symptoms?
Routine bowel screening is intended for people without symptoms. If you have rectal bleeding, persistent bowel changes or other concerning symptoms, arrange a medical assessment rather than relying on a screening test.
Should I start bowel cancer screening before 45 if it runs in my family?
Possibly. Screening recommendations for people with a significant family history can differ from population screening recommendations. Your GP can review which relatives developed bowel cancer, their ages at diagnosis, and whether you may need earlier surveillance or specialist assessment.
What happens after a positive bowel screening test?
A positive iFOBT means that blood has been detected in the stool. It does not diagnose cancer. Your doctor will discuss the result with you and arrange appropriate further investigation, which may include referral for colonoscopy.
Speak With a GP About Changes in Your Bowel Health
If you have persistent bowel symptoms, rectal bleeding, unexplained iron deficiency or concerns about your family history, consider discussing them with a GP.
You can book an appointment with Capstone Medical Centre Southbank for an individual assessment and advice about appropriate next steps.
References
- Australian Government Department of Health, Disability and Ageing. National Bowel Cancer Screening Program.
- Australian Government Department of Health, Disability and Ageing. Who should do the bowel screening test – and who should not.
- Cancer Council Australia. Bowel Cancer.
- Australian Institute of Health and Welfare. Cancer Data in Australia.
- World Cancer Research Fund. Colorectal Cancer: Diet, Nutrition, Physical Activity and Cancer Prevention.
- Arnold M, et al. International trends in the incidence of early-onset colorectal cancer. The Lancet Oncology.
Disclaimer: This article provides general health information and does not replace personalised medical advice. If you have symptoms or concerns about your bowel health, speak with a qualified healthcare professional.
