Dr. Deenadayalan T explains the early warning signs of cancer (Tamil).
The most common early warning signs of cancer are unexplained weight loss, a new lump or swelling, unusual bleeding, a sore or ulcer that does not heal, a persistent cough or hoarseness, and a lasting change in bowel or bladder habits. None of these symptoms means you have cancer. But any of them lasting more than two to three weeks needs to be examined by a doctor.
Most people who notice one of these symptoms do not have cancer. That is the honest starting point. The reason they still matter is timing: when cancer is found early, the odds change completely — and in India, they usually are not found early.
Why early detection changes the outcome
Stage at diagnosis is the single biggest predictor of survival in most cancers — bigger than the treatment chosen. Breast cancer shows the pattern most clearly, and the same shape holds across colorectal, cervical, oral and many other cancers: catch it while it is still local, and survival is close to normal.
| Stage at diagnosis (breast cancer) | 5-year relative survival |
| Localized — confined to the breast | ~99% |
| Regional — spread to nearby lymph nodes | ~86% |
| Distant — spread to other organs | ~31% |
Source: SEER / American Cancer Society. Figures are population averages, not individual predictions.
That is the whole argument for not waiting. The difference between a 99% and a 31% five-year survival is not a better drug. It is a few weeks of attention.
The cancer picture in India
India recorded an estimated 1,413,316 new cancer cases and 916,827 cancer deaths in 2022 (GLOBOCAN, IARC). That works out to roughly three deaths for every five diagnoses — a far worse ratio than in high-income countries, and it is driven largely by how late patients present.
India is also a global outlier in one respect: worldwide, lung cancer kills the most people, but in India oral cancer causes the highest number of cancer deaths — a direct consequence of tobacco and gutkha use. A non-healing mouth ulcer is therefore not a minor complaint in this country. It is one of the most important symptoms on this page.
10 early warning signs of cancer you should not ignore
1. Unexplained weight loss
Losing weight without changing your diet, exercise or lifestyle is a recognised warning sign in several cancers, including pancreatic, stomach, oesophageal and lung cancer. A useful threshold: losing more than 5% of your body weight in 6 to 12 months without trying should be investigated. For a 70 kg adult, that is about 3.5 kg.
2. A lump, swelling or thickening
Any new lump in the breast, neck, armpit, groin, testicle or anywhere else should be examined. Most lumps are benign — cysts, lipomas, reactive lymph nodes. But a lump that is hard, painless, fixed to underlying tissue, and growing carries more concern than one that is soft, mobile and tender. You cannot reliably tell the difference yourself, and neither can a doctor without imaging or a biopsy.
3. A sore or ulcer that does not heal
Ordinary mouth ulcers heal in 7 to 14 days. Any ulcer — in the mouth, on the tongue, on the skin, anywhere — that has not healed after three weeks needs a specialist opinion. Given that oral cancer is India’s leading cause of cancer death, this is the symptom that is most often dismissed and most costly to dismiss. If you chew tobacco, betel quid or gutkha, treat any persistent mouth patch or ulcer as urgent.
4. Unusual bleeding or discharge
Bleeding without an obvious cause should always be explained, not assumed away. This includes blood in the stool (often wrongly blamed on piles), blood in the urine, coughing up blood, vomiting blood, bleeding gums that do not settle, and any unusual vaginal discharge or bleeding.
5. A change in bowel or bladder habits
A persistent change in your normal pattern matters more than any single episode. Watch for constipation or diarrhoea lasting several weeks, narrower stools, a feeling of incomplete emptying, difficulty passing urine, or a new urgency or frequency.
6. A persistent cough or hoarseness
A cough that has not resolved after three weeks — especially in a smoker or ex-smoker — needs a chest X-ray at minimum. Hoarseness of voice lasting more than three weeks is a red flag for laryngeal cancer and is frequently mistaken for a lingering throat infection.
7. Difficulty swallowing
Progressive difficulty swallowing — starting with solids, later with liquids — is a classic presentation of oesophageal cancer. It is not a normal part of ageing and should never be managed with home remedies.
8. Extreme, unexplained fatigue
Everyone gets tired. Cancer-related fatigue is different: it does not improve with rest, it is out of proportion to your activity, and it interferes with normal daily function. It is a common early sign in leukaemia, lymphoma and colon cancer (where it is often driven by slow, invisible blood loss).
9. Persistent low-grade fever and night sweats
A low-grade fever running for weeks with no infection found, or drenching night sweats that soak through clothing and bedsheets, are recognised features of lymphoma and leukaemia. In India these are often treated repeatedly as typhoid or tuberculosis before anyone looks further.
10. A changing mole or skin lesion
Use the ABCDE rule: Asymmetry, irregular Borders, uneven Colour, Diameter over 6 mm, and Evolving — changing in size, shape, colour, or beginning to itch or bleed. Any mole that is changing should be assessed for melanoma.
Warning signs women should never ignore
Two symptoms in women carry particular weight because they are strongly associated with gynaecological cancers and are still routinely delayed out of embarrassment.
- Postcoital bleeding — bleeding after intercourse. A recognised warning sign of cervical cancer, which is one of the most common cancers in Indian women and is almost entirely caused by HPV infection.
- Postmenopausal bleeding — any vaginal bleeding after menopause. This is never normal and always requires evaluation. It is the classic presentation of endometrial (uterine) cancer.
Cervical cancer is also one of the few cancers that is genuinely preventable — through HPV vaccination and regular Pap or HPV screening.
The three-week rule: when to see a doctor
The simplest rule to remember: if an unexplained symptom has lasted more than two to three weeks, get it checked. Do not self-medicate, do not wait for it to pass, and do not wait for it to become painful. Most cancers are painless in their early stages — pain is usually a late symptom, not an early one.
| Symptom | Get it checked if it lasts | Typical first step |
| Mouth ulcer or white/red patch | Over 3 weeks | Oral examination, biopsy |
| Cough or hoarseness | Over 3 weeks | Chest X-ray, ENT scope |
| Lump anywhere | Immediately, if new or growing | Ultrasound / mammogram, FNAC or biopsy |
| Blood in stool | Immediately — do not assume piles | Colonoscopy |
| Postmenopausal bleeding | Immediately — any amount | Ultrasound, endometrial biopsy |
| Unexplained weight loss | Over 5% body weight in 6 months | Blood tests, imaging |
If a symptom is confirmed as suspicious, the next step is usually a biopsy. If you are worried about that, read: What Is a Biopsy? Types, Procedure and Myths Explained — including why a biopsy does not spread cancer.
Frequently asked questions
Do these symptoms always mean cancer?
No. Most people with these symptoms do not have cancer. Fatigue, weight change, cough and bleeding all have common, harmless explanations. The purpose of evaluation is not to confirm cancer — it is to rule it out quickly so you can stop worrying, or to catch it while it is still curable.
Is cancer curable if detected early?
Many cancers are curable when detected early. Localised breast, cervical, colorectal, oral, thyroid and testicular cancers all have high cure rates when treated at an early stage. Cure rates fall sharply once the cancer has spread to distant organs, which is why timing matters more than almost anything else.
Is cancer painful in the early stages?
Usually not. Most early cancers are painless. Waiting for pain before seeking help is one of the most common reasons cancer is diagnosed late. A painless lump is not a reassuring lump.
Which doctor should I see for these symptoms?
Start with your general physician, who can order initial tests. If a scan, blood test or biopsy raises suspicion of cancer, you will be referred to a medical oncologist. You can also consult an oncologist directly for a second opinion at any point — you do not need a confirmed diagnosis to ask.
Should I get screened if I have no symptoms?
Yes, for certain cancers. Screening is designed to find cancer before symptoms appear — mammography for breast cancer, Pap/HPV testing for cervical cancer, and oral examination if you use tobacco. Screening schedules depend on your age, sex, family history and risk factors, and should be discussed with a doctor.
Key takeaway
Cancer almost always gives warning before it becomes advanced. The signs are rarely dramatic — a lump, an ulcer that will not heal, a cough that will not clear, weight that keeps dropping. Three weeks is the line. Past that, get it examined. The symptom is probably nothing. But if it is something, the weeks you save are the ones that decide the outcome.
Consult a medical oncologist in Madurai
Dr. Deenadayalan T is a Consultant Medical Oncologist in Madurai. His practice covers early cancer diagnosis and screening, chemotherapy, targeted therapy, immunotherapy and personalised cancer care.
Sources
- International Agency for Research on Cancer — Global Cancer Observatory, India fact sheet (GLOBOCAN)
- American Cancer Society — Breast cancer survival rates (SEER)
- National Cancer Institute — SEER Cancer Stat Facts
Medically reviewed by Dr. Deenadayalan T, MD, DM (Medical Oncology). Last reviewed: [15 July 2026]. This article is for general information only and is not a substitute for professional medical advice, diagnosis or treatment. Always consult a qualified doctor about your own symptoms.