Why Are Some Cancers Only Found at Stage 3 or 4?
A late diagnosis does not always mean someone ignored their health. Some cancers cause few early symptoms, while others produce signs that resemble common everyday problems. Here is what to watch for—and when screening may help.
Illustrative image | AI-generated
This article provides general information and does not diagnose cancer or replace medical advice. Screening recommendations vary by age, sex, family history and personal risk. Speak with a healthcare professional about what is appropriate for you. Seek prompt care for severe or worsening symptoms.
HEALTH NEWS — Public conversations about advanced cancer, including Sheikh Haikel’s disclosure of Stage 4 colorectal cancer, have led many people to ask a difficult question: why can cancer remain undetected until Stage 3 or Stage 4?
There is no single explanation. Some cancers grow quietly. Some occur in parts of the body where a tumour can become sizeable before causing obvious problems. Symptoms may also be mild, intermittent or mistaken for stress, ageing, indigestion, piles or another common condition.
It is important not to blame the patient. Even a health-conscious person may develop a cancer for which there is no routine population screening test.
Screening looks for certain cancers in people who do not have symptoms. If you have a persistent or concerning symptom, do not wait for your next screening invitation—consult a doctor for an assessment.
What Do Stage 3 and Stage 4 Mean?
The exact meaning depends on the cancer type. In general, Stage 3 often means the cancer has grown more deeply or reached nearby lymph nodes or tissues. Stage 4 usually means it has spread to a distant part of the body. Doctors also consider the tumour’s biology, location and the person’s overall health when planning treatment.
Stage alone does not tell the full story, and it should not be used to predict an individual patient’s outcome without medical assessment.
What Singapore’s Registry Data Show
The latest Singapore Cancer Registry annual report available for this article covers diagnoses through 2023. It does not provide a single annual count called “people first diagnosed at Stage 4” across every cancer from 2020 to 2026. Reporting percentages for specific cancers is therefore more accurate than inventing a nationwide total.
| Cancer diagnosed in 2019–2023 | Men diagnosed at Stage IV | Women diagnosed at Stage IV |
|---|---|---|
| Lung cancer | 60.3% | 59.6% |
| Pancreatic cancer | 57.1% | 54.5% |
| Colorectal cancer | 25.6% | 25.9% |
These figures describe the stage distribution among registered cases of each cancer and sex—not the percentage of Singapore’s general population. Data for 2024–2026 are not yet included in that registry report.
Why Can Cancer Be Found Late?
Some tumours can grow without causing clear pain or a noticeable change.
Fatigue, bloating, cough or bowel changes may initially resemble common conditions.
Population screening is available for only some cancers, not every cancer.
Fear, cost, busy schedules or hoping a symptom will disappear can postpone a visit.
Warning Signs That Deserve Attention
Most of these symptoms are not caused by cancer. However, a new, unexplained or persistent change should be discussed with a doctor—especially if it worsens or affects daily life.
- An unexplained lump, swelling or thickening
- Blood in the stool or urine, or unexplained bleeding
- A lasting change in bowel or bladder habits
- Unexplained weight loss or loss of appetite
- A cough, hoarseness or breathlessness that does not settle
- Difficulty swallowing or persistent indigestion
- A sore that does not heal
- A changing mole or unusual skin change
- Persistent pain, bloating or unusual fatigue
Cancer does not always cause pain at an early stage. A symptom’s persistence, progression and unexplained nature may matter more than whether it hurts.
When Should You See a Doctor?
There is no universal number of days that applies to every symptom. Arrange a medical review when a change is unexplained, keeps returning, lasts longer than expected or becomes worse. Go sooner if you have bleeding, a growing lump, significant weight loss, trouble swallowing, breathlessness or severe symptoms.
Tell the doctor when the symptom started, whether it is changing, any medicines you take, and whether close relatives have had cancer. A consultation does not automatically mean cancer testing; the doctor will decide what examination or investigation is appropriate.
Which Cancer Screenings Are Available in Singapore?
Singapore’s Screen for Life programme supports recommended screening for selected cancers. Eligibility and intervals depend on factors such as age and risk.
For average-risk adults, screening commonly begins from age 50 using a faecal immunochemical test, with colonoscopy used in appropriate circumstances.
Mammography recommendations depend on age and risk. Women should check the current Screen for Life guidance.
HPV testing or a Pap test may be recommended depending on age and screening history.
A doctor may recommend a different plan when there is strong family history, inherited risk or previous abnormal findings.
Continue paying attention to new symptoms between screening rounds. Screening can reduce risk of late detection, but no test finds every cancer and false-negative results can occur.
Can a Full-Body Check-Up Find Every Cancer?
No. There is no single blood test, scan or health package that reliably rules out every cancer in a person without symptoms. More testing is not always better: unnecessary tests can produce false alarms, radiation exposure, invasive follow-up procedures and extra cost.
Choose evidence-based screening for your age and risk, and seek assessment when symptoms appear. Discuss add-on tests with a doctor instead of assuming the largest package is automatically the safest.
How Can You Prepare for a Check-Up?
- Write down symptoms, dates and how often they occur.
- List current medicines and supplements.
- Know your immediate family’s cancer history where possible.
- Bring previous screening or scan results.
- Ask which test is recommended, what it can detect and what its limitations are.
- Ask when and how you will receive the result.
Key Takeaways
- A late diagnosis does not necessarily mean a person neglected their health.
- Some cancers cause few early symptoms, and not every cancer has a routine screening test.
- Singapore registry data for 2019–2023 show that Stage IV presentation varies greatly by cancer type.
- Screening is for people without symptoms; persistent symptoms require medical assessment.
- Do not wait for pain before discussing an unexplained or worsening change with a doctor.
- Screening should match your age, sex, history and individual risk.
Sources & References
- Singapore Cancer Registry Annual Report 2023, National Registry of Diseases Office. Published January 2026.
- Screen for Life, Health Promotion Board, Singapore.
- Cancer Staging, US National Cancer Institute.
- Cancer Fact Sheet, World Health Organization.
About KnowvaLife
KnowvaLife is a Singapore-based health information and media platform providing practical, evidence-informed health content in clear, easy-to-understand language.
