What screening is, and what it is not
means looking for cancer before a person has any symptoms. A screening test usually does not diagnose cancer. It picks out the people who need more tests, such as a , to check whether cancer is there.
Screening has limits. A test can miss a cancer, and a person who is falsely reassured may delay seeing a doctor even if symptoms appear later. A test can also suggest cancer when there is none, which causes worry and leads to more tests. Some screening finds cancers that would never have caused harm. This is why the decision to be screened is shared between you and your doctor.
What India's national programme offers
| Cancer | Who | Check | How often |
|---|---|---|---|
| Mouth | Men and women aged 30 and over | Looking inside the mouth, done by a trained health worker | Once in five years |
| Breast | Women aged 30 to 65 | Breast examination by a trained health worker | Once in five years |
| Cervix | Women aged 30 to 65 | Visual inspection of the cervix with acetic acid (VIA) | Once in five years |
The checks are done at health centres such as an Ayushman Arogya Mandir, after a health worker has asked about risk factors. Anyone whose check is positive is referred to a higher centre, where tests such as a , a breast or an examination by a gynaecologist confirm whether it is cancer.
What other bodies advise
WHO advises for cervical cancer with a high-performance test every 5 to 10 years, starting at age 30. US advice, summarised by MedlinePlus, is a Pap test every 3 years, an test every 5 years, or both every 5 years, for women aged 30 to 65.
For breast cancer, WHO defines mammography screening as usually for women aged 50 to 69 and notes that it is impractical in many countries at present. US advice is for mammograms from age 40, every 1 to 2 years, and says expert groups differ. These are advice from other bodies, not India's national programme.
Signs that need a doctor without waiting
- Mouth: an ulcer that does not heal or grows, white, red or dark patches, a lump, pain that lasts, trouble chewing, swallowing, speaking or opening the mouth, or a tooth socket that does not heal
- Breast: a lump or thickening, often painless, a change in size or shape, dimpling, redness or puckering of the skin, a nipple turning inwards, or unusual or bloody nipple discharge
- Cervix: bleeding between periods, after sex or after the menopause, unusual or foul-smelling vaginal discharge, or pelvic, back or leg pain that does not settle
Lowering the risk
In India's national guidance, chewing tobacco is the single most important risk factor for mouth cancer. Alcohol, betel nut and a sharp tooth or ill-fitting denture that keeps injuring the mouth also add to the risk.
Almost all cervical cancers are caused by infection with the human papillomavirus (). WHO says HPV vaccination of girls aged 9 to 14 is highly effective at preventing infection, cervical cancer and other HPV-related cancers. Smoking also raises the risk of cervical cancer.
Common questions
If my screening result is normal, am I safe from cancer?
A normal result is reassuring, but no test finds every cancer, and cancer can start after a test. Go back for the next round, and see a doctor if a new symptom appears, whatever your last result was.
What happens if the result is positive?
A positive screen is not a diagnosis. It means more tests. In India's programme, people with a positive result are referred to a higher health centre for tests such as a biopsy, which show whether it is cancer.
I am under 30. Is there a screening programme for me?
India's national programme starts at 30. If you are younger and notice a lump, a mouth sore that does not heal or unusual bleeding, see a doctor, as these need to be examined at any age. For girls aged 9 to 14, WHO advises HPV vaccination.
Why do some countries start mammograms at 40 and others at 50?
Expert groups weigh benefits and harms differently, and WHO notes that mammography screening is impractical in many countries at present. India's programme uses a breast examination by a trained health worker instead. Ask your doctor which advice suits you.
