Cancer Screening Tests Explained: What Works in India and What Is Just Marketing

In my previous post I explained cancer warning signs — what to do when you have symptoms. Screening is different: it means testing healthy people without symptoms to find cancer or pre-cancer early, when treatment is simpler and more successful.

But not every test is a good screening test. A good one must find disease early, be accurate, and — most importantly — reduce deaths in large trials. Let’s separate what works from what is marketing.

First, understand the two groups of tests

Type	Examples	Can it screen for cancer?
General health tests	CBC, CRP/ESR, sugar, lipids, liver and kidney tests, TSH, vitamin D, ferritin	No. They show general body changes. An abnormal value only means “investigate further”.
Cancer-specific screening tests	Mouth examination, clinical breast examination, VIA/Pap/HPV test, mammography, stool test/colonoscopy, low-dose CT for eligible smokers	Yes — for the right age and risk group, and when proven in trials.

Unexplained anaemia or iron deficiency in an adult (especially a man or a woman after menopause) is a reason to see a doctor, as it can sometimes point to bleeding in the gut.

India’s national screening: free for everyone aged 30–65

Under NP-NCD, the Ministry of Health’s framework recommends these three tests once every 5 years for people aged 30–65, done by trained health workers at Ayushman Arogya Mandirs and government health centres:

Cancer	Test	Evidence from India
Oral (mouth)	Oral Visual Examination (OVE) — a simple look inside the mouth	In a large Kerala trial, mouth examination reduced oral cancer deaths among tobacco and alcohol users (Lancet 2005)
Breast	Clinical Breast Examination (CBE) by a trained health worker	In a 20-year Mumbai trial, CBE every 2 years found cancers at an earlier stage. The overall fall in breast-cancer deaths (about 15%) was not statistically significant; the often-quoted ~30% reduction was seen in women aged 50+ in a subgroup analysis, so it should be read as encouraging, not conclusive (BMJ 2021)
Cervix	Visual Inspection with Acetic acid (VIA)	Low-cost, same-day test widely used in India

Cervical cancer: the most preventable cancer

• WHO (2021) recommends an HPV DNA test as the preferred screening test, starting at age 30, repeated every 5–10 years. VIA or Pap tests are alternatives where HPV testing is not available.
• A landmark trial in rural Maharashtra found that a single HPV test reduced advanced cervical cancer and deaths by about half (NEJM 2009).
• The HPV vaccine prevents most cervical cancers — it works best when given to girls before they become sexually active (WHO recommends it for ages 9–14).
• Pap tests every 3 years from age 21 (as in your US-style lists) are used in some countries; in India, follow NP-NCD or your gynaecologist’s advice.

Breast cancer

• Breast awareness: know how your breasts normally look and feel, and report changes early.
• Clinical breast examination: free under NP-NCD from age 30.
• Mammography: the US Preventive Services Task Force (2024) advises it every 2 years for women 40–74. In India, there is no national mammography programme; your doctor may advise it based on age, risk and family history.
• Women with a strong family history (mother/sister with breast or ovarian cancer, known BRCA mutation) may need earlier or more intensive screening — ask a specialist.

Colorectal, lung and prostate cancer

Cancer	Screening abroad	Indian context
Colon and rectum	USPSTF: from age 45 to 75 — stool test (FIT) every year or colonoscopy every 10 years	No national programme yet. Discuss if you have a family history, bleeding or change in bowel habits
Lung	USPSTF: yearly low-dose CT for ages 50–80 with a heavy smoking history (20 pack-years) who smoke now or quit within 15 years	Not for non-smokers. A chest X-ray is not a screening test. In India, TB can cause confusing CT findings — decide with a specialist
Prostate (men)	USPSTF: PSA test is an individual decision at 55–69 after discussing benefits and harms	PSA can be high due to age, infection or an enlarged prostate. Decide with a doctor

Tumour markers are not screening tests

A random “cancer marker package” can cause false alarms, fear and costly scans — or false reassurance.

What about new “one blood test for many cancers”?

Multi-cancer detection (MCD) blood tests look for cancer DNA in the blood. As of September 2026, the US National Cancer Institute notes there is no proof yet that they reduce cancer deaths, and no guideline recommends them for routine screening. The first such test (Galleri) is under US FDA review, with an FDA advisory committee voting in favour of approval in September 2026 for adults aged 50 and over (7–2 on benefit–risk, 6–4 on effectiveness). That vote is advice only: the FDA has not approved it as a screening test, and a final decision is expected in the coming months. They can miss cancers and give false positives. They do not replace the proven tests above.

Between screenings: the two levers with real evidence

Screening finds cancer early. It does not lower your chance of getting it. Two things do, with evidence the World Cancer Research Fund grades as convincing — and neither is a supplement.

Movement

Physical activity is graded convincing for lower risk of colon, endometrial and post-menopausal breast cancer. The usual target is 150 minutes of moderate activity a week, or about twenty minutes a day.

It does not have to be a gym. Walking counts, housework counts, stairs count. What matters is that it is regular rather than heroic once a month.

• 150 minutes a week of moderate activity, or 75 of vigorous
• Spread across the week, not saved for Sunday
• Sitting time matters separately — break it up

Weight

Greater body fatness is graded a convincing cause of several cancers, including bowel, endometrial and post-menopausal breast. This is one of the few modifiable risk factors on the list.

The number itself matters less than the direction it moves over months. Weigh at the same time of day, on the same surface, and record it.

Unexplained weight loss is a different matter entirely — that is an alarm symptom, not a success, and it needs a doctor.

Waist

Where fat sits matters, and waist circumference picks up what the scale misses. Someone whose weight has not changed in five years can still have added several inches at the waist.

Measure at the level of the navel, standing relaxed, at the end of a normal breath out.

Once a month is enough. A rising trend across months is the signal; any single reading is noise.

Key reminders

• A screening result is a signal, not a diagnosis. Diagnosis needs examination, imaging and usually a biopsy.
• A normal screening test does not mean you can ignore new symptoms — see the CAUTION+ signs.
• Prevention matters too: no tobacco, limit alcohol, HPV and hepatitis B vaccination, healthy weight and activity.

Key takeaways

1. Aged 30–65? Free mouth screening for everyone, and breast and cervical screening for women, under NP-NCD — once every 5 years.
2. Women: HPV testing from 30 is the best cervical screening where available; the HPV vaccine prevents most cervical cancer.
3. Mammography, colon, lung and prostate screening depend on age and risk — decide with your doctor.
4. Tumour markers and multi-cancer blood tests are not routine screening tests.

Related reading

• Cancer warning signs: the CAUTION checklist

Sources

1. MoHFW. Operational Framework: Management of Common Cancers (2016) — OVE, CBE and VIA once in 5 years for ages 30–65
2. MoHFW / PIB. Intensified NCD Screening Drive for all aged 30+ under NP-NCD (2025) — free oral, breast and cervical screening
3. WHO. New recommendations for screening and treatment to prevent cervical cancer (2021) — HPV DNA test from 30, every 5–10 years
4. Sankaranarayanan R et al. HPV Screening for Cervical Cancer in Rural India, NEJM (2009) — a single HPV test cut advanced cancers and deaths by about half
5. Mittra I et al. Clinical breast examination screening: 20-year cluster randomised trial in Mumbai, BMJ (2021) — fewer late-stage cancers; overall mortality reduction not statistically significant, ~30% fewer deaths in the 50+ subgroup
6. Sankaranarayanan R et al. Effect of screening on oral cancer mortality in Kerala, Lancet (2005) — mouth examination reduced oral cancer deaths in tobacco/alcohol users
7. USPSTF. Breast Cancer: Screening (2024) — mammography every 2 years, age 40–74
8. USPSTF. Colorectal Cancer: Screening (2021) — age 45–75
9. USPSTF. Lung Cancer: Screening (2021) — yearly low-dose CT, age 50–80 with 20 pack-year history
10. USPSTF. Prostate Cancer: Screening (2018) — PSA is an individual decision at 55–69
11. National Cancer Institute. Questions and Answers about Multi-Cancer Detection Tests — no proof yet that they reduce cancer deaths
12. GRAIL. FDA Advisory Committee meeting to review Galleri PMA (August 2026) — status of the first multi-cancer blood test under FDA review

What actually lowers your risk. Worrying does not. WCRF/AICR grades the evidence as convincing that regular physical activity lowers the risk of colon cancer, post-menopausal breast cancer and endometrial cancer — alongside not smoking, limiting alcohol and keeping a healthy weight. None of this treats a symptom you already have. If you have one, see a doctor rather than changing your routine and waiting.