Screening can detect bowel cancer at an early stage in people with no symptoms, when it is easier to treat. Sometimes it can prevent bowel cancer from even developing in the first place by picking up non-cancerous growths (polyps) which could become cancerous in the future.
Since its introduction, the NHS bowel cancer screening programme has been shown to be the most effective method of detecting bowel cancer early. Not only does screening pick up bowel cancer in the earliest stage of disease, it can also detect dangerous polyps which may develop into bowel cancer.
That's certainly the case for prostate cancer screening in men, according to researchers in Canada who last week recommended scrapping PSA (prostate-specific antigen) testing, even for those considered high risk.
It's astonishing to realise that in spite of our advanced medical technology and years of dedicated research, there are no biomarkers approved for the screening of breast or lung cancer - the two most cancers for men and women around the world.
When it comes to screening, it's not a bad idea to look before you leap. Don't fall for the old lead time bias, or the description of the test being initially 'simple' - ask how having screening affects the mortality rate, weigh up the pros and cons, and make up your own mind.
Every year, Human Rights Day spurs debate around the world about what constitutes a human right. Much-vaunted, often controversial, and little understood, it seems there's still a great deal of contention about which rights are most important.