Why isn't screening available for all cancers?
A screening programme needs to have a good enough test for it to work. This test must:
- reliably detect any cancers or abnormal changes that could lead to cancer
- not cause too many false alarms
- be acceptable, so that people will actually take the test
- not be dangerous to health
- be cost-effective.
If a test doesn’t do these things, it’s unlikely to work well for screening the whole population.
If a cancer is rare, screening everyone wouldn’t work, and it would be harder for the benefits to outweigh the harms across everyone taking part. If good tests are available for rarer cancers, doctors will often offer them to people who are at highest risk of the disease.
If there isn’t a good enough test, or screening would do more harm overall to people taking part, then it isn’t introduced.
At the moment, there isn’t enough evidence to say that screening for any type of cancer other than breast, bowel, and cervical cancer would be a good idea.
But researchers are always looking for new tests and new ways to spot cancers early, and there are some types of cancer where research into screening is growing, for example, lung and ovarian cancers.
The PSA test for prostate cancer
There is no screening programme for prostate cancer because we don’t have a reliable enough test to use, and the test available at the moment has significant risks.
A test called the prostate specific antigen (PSA) test has been looked at to see if it could be used to screen for prostate cancer. But this test is not reliable enough to use for screening.
Overall, the evidence shows that screening for prostate cancer doesn’t reduce the number of men dying from the disease, but does increase the risk of harms such as overdiagnosis, where slow-growing tumours that wouldn’t cause a man any harm are picked up. It can also miss prostate cancers which did need to be found and treated.
If you’re over 50 you can ask your doctor about the prostate specific antigen (PSA) blood test. Having this test carries risk so if you ask for this test, your doctor will discuss it with you.
Research into screening for lung cancer
At the moment there is no screening programme for lung cancer in the UK.
There have been some trials looking at using a type of CT scan to screen for lung cancer in older smokers or ex-smokers. There is some evidence that this type of screening could save lives from lung cancer. But it also looks like it will lead to unnecessary diagnosis and treatment, so the balance of benefit to harm isn’t fully clear yet.
There is another big trial going on in Europe at the moment, which should provide more information. Then, the National Screening Committee will look at the evidence and decide whether screening should be introduced in the UK.
Research into screening for ovarian cancer
At the moment, there is no screening programme for ovarian cancer in the UK.
The trials to date haven’t been able to show that it would save lives from the disease. A UK trial is following women up for longer to be sure the results continue to hold true.