Why the Age You Start Screening Matters
Bowel cancer rarely causes symptoms in its early stages. By the time something feels wrong — pain, bleeding, a change in how your bowel works — the cancer may already have grown to a more advanced stage. This is why screening matters: it looks for problems before your body has given you any signals.
Roughly 1 in 14 Australians will develop bowel cancer in their lifetime. The risk increases with age, but bowel cancer is increasingly being found in younger adults too — which is why knowing your own risk profile, and not just waiting for a kit to arrive in the post, is more important than ever.
The National Bowel Cancer Screening Program
If you are aged 45 to 74, Australia's National Bowel Cancer Screening Program (NBCSP) automatically sends you a free bowel test kit every two years, linked to your Medicare enrolment. You do not need to ask for it or pay anything. The test is called an FOBT — a faecal occult blood test (FOBT). You collect small stool samples at home from two separate bowel motions, then post them back to the lab in the prepaid envelope provided.
The FOBT checks for traces of blood in your stool that are invisible to the naked eye. Blood in your stool can be an early sign of a bowel polyp or a cancer. A positive result does not mean you have cancer — it means blood was detected, and a follow-up colonoscopy is needed to find out why.
Have not received a kit? If you are aged 45–74 and have not received your FOBT kit, call the NBCSP on 1800 627 701 or visit cancerscreening.gov.au. Fewer than half of eligible Australians complete the test each time it is sent. Please do not let yours be a missed opportunity.
The FOBT is not a perfect test. Some cancers and polyps only bleed intermittently, so a negative result does not completely rule out a problem. This is why completing the test every two years — not just once — is so important.
How to Do the FOBT Kit
The whole process can be done at home in a few minutes across two mornings. Here is what it involves:
Open the kit and read the instructions. You do not need to change your diet or stop any medications beforehand.
Collect a small stool sample from your first bowel motion using the sampling stick, and apply a small amount to the test card as instructed.
Repeat the process with a second bowel motion on a different day.
Seal the test card in the biohazard bag provided and return it using the prepaid reply envelope.
Your result is sent to you and your GP within 2–4 weeks. If it is positive, your GP will refer you for a colonoscopy — please act on that promptly.
Which Screening Pathway Applies to You?
Not everyone should rely solely on the NBCSP FOBT. Your level of risk determines how and when you should be screened. Use the table below as a starting point, and talk to your GP or a colorectal surgeon about your individual situation.
Screening Pathway by Risk Level
| Risk Level | Who This Applies To | Recommended Approach |
|---|---|---|
| Average | No personal or family history of bowel cancer or polyps; no symptoms | Free NBCSP FOBT kit every 2 years from age 45 to 74, via Medicare |
| Moderate | One first-degree relative (parent, sibling, child) with bowel cancer; or personal history of bowel polyps | Colonoscopy from age 40–45, or 10 years before your relative's diagnosis age (whichever comes first); repeated every 5 years |
| High | Two or more first-degree relatives with bowel cancer; one relative diagnosed under 55; known or suspected Lynch syndrome or FAP; personal history of bowel cancer | Colonoscopy from age 25–35 depending on your specific situation; genetics referral; specialist colorectal surgeon involvement |
These recommendations follow Australian NHMRC guidelines. If you are not sure which category fits your situation, your GP can work through it with you and arrange the right referral.
If You Have a Family History
Having a parent, sibling, or child who has had bowel cancer roughly doubles your lifetime risk compared to someone with no family history. If that relative was diagnosed before age 55, or if more than one close relative is affected, your risk is higher still — and the FOBT programme alone is not sufficient.
In this situation, colonoscopy — not FOBT — is the right primary screening tool. A colonoscopy lets the specialist look directly at your bowel, find polyps early, and remove them before they have a chance to become cancer. Your GP can refer you to a colorectal surgeon for an assessment and a personalised screening plan.
Hereditary Bowel Cancer Syndromes
A small proportion of bowel cancers are caused by inherited gene changes that can be passed through families. The two most important are:
- Lynch syndrome: caused by changes in DNA repair genes. If you carry a Lynch syndrome gene change, your lifetime bowel cancer risk is 40–80%. Colonoscopy every 1–2 years from age 25 is recommended.
- Familial adenomatous polyposis (FAP): caused by a change in the APC gene. Hundreds of polyps develop throughout the colon from a young age, and without treatment, bowel cancer is almost inevitable. Surveillance begins in teenage years, and surgery to remove the colon is usually advised before cancer develops.
If bowel cancer runs strongly through your family — especially in multiple generations or at young ages — a referral to a hereditary cancer genetics clinic is worth discussing with your GP. Genetic testing can clarify your family's risk and guide screening recommendations for you and your relatives.
What to Do After a Positive FOBT
If your FOBT comes back positive, you need a colonoscopy — ideally within 30 days. Please do not put this off. A colonoscopy allows the specialist to look directly at your entire bowel lining, take a biopsy of anything suspicious, and remove any polyps found on the spot.
Medicare covers colonoscopy after a positive NBCSP FOBT result. Your GP will provide the referral. If you need to arrange this promptly, you can also contact our rooms directly on (03) 9816 3951.
What If You Are Under 45?
The National Bowel Cancer Screening Program does not cover people under 45. But that does not mean you should wait. If you have symptoms — rectal bleeding, a persistent change in bowel habit, unexplained weight loss, or unexplained iron deficiency — or if you have a family history of bowel cancer, please see your GP now rather than waiting until you turn 45.
Bowel cancer in adults under 50 is becoming more common, and one of the main reasons it is found late in younger people is that symptoms are dismissed because of age. Your age should not be the reason an investigation is delayed.
Frequently Asked Questions
The kit should arrive automatically through your Medicare enrolment. If it has not arrived, call the NBCSP on 1800 627 701 or visit cancerscreening.gov.au. Your GP can also help you request a kit.
It is never too late. Return the kit even if it is past the suggested date on the packaging. If it has expired, contact the NBCSP for a replacement. The important thing is that you do it.
A negative FOBT result is reassuring, but it is not a guarantee. Some cancers and polyps only bleed intermittently and may not have been bleeding when your sample was collected. Continue doing the FOBT every two years through the programme, and see your GP if any symptoms develop in between.
Yes — some people, particularly those with a family history or personal risk factors, go directly to colonoscopy with a GP referral rather than doing the FOBT. Colonoscopy is more thorough than FOBT and can both detect and remove polyps in a single procedure. Discuss this option with your GP.
With one first-degree relative diagnosed at any age, current Australian guidelines recommend colonoscopy from age 40–45, or 10 years before the age your mother was diagnosed — whichever comes first. Ask your GP for a referral to a colorectal surgeon to work out a screening plan specific to your situation.
The NBCSP FOBT kit is free regardless of whether you have private health insurance. Colonoscopy after a positive FOBT is covered by Medicare. Private health insurance may allow you to choose your own specialist and access shorter waiting times for elective colonoscopy, but it is not required.
Not sure which screening pathway applies to you?
Mr Ba Nguyen offers specialist colorectal consultations for patients who want to understand their personal bowel cancer risk. A GP referral is required. Call (03) 9816 3951 or ask your GP to refer you to North Eastern Surgical in Heidelberg.