Trials are looking at screening in other cancers. An example of this is lung cancer. In the USA a randomised trial, the National Lung Screening Trial (NLST), was launched in 2002. People were randomised to receive either spiral CT or scan or chest x ray and will have the same screening procedure one and two years later. The study aims to show if either test is better at reducing deaths from this disease.

Nearly 50,000 current or former smokers are involved in the NLST across the US and will be followed up yearly to monitor their health (47).

In the UK ,a trial is looking at the use of bronchoscopy for people who are at high risk of lung cancer. This is called fluorescence bronchoscopy and involves using a blue light and white light to examine the lining of the airways. The trial finished recruiting in 2005 and the results have not yet been released (48).

The difficulty with screening for lung cancer is that the lungs are very sensitive to radiation so having regular x rays could potentially be harmful. To screen for lung cancer, a test is needed that is simple, quick, not too expensive and not harmful. It is always cost effective to screen people who are known to be at a higher risk, such as people who smoke.

Overview of UK cancer screening programmes

Cervix

• Current status of screening The screening programme became available nationwide in 1988. The aim is to detect pre cancerous changes in the cervix.
• What the screening programme involves Women who are aged from 25-49 years are invited to have a smear test every 3 years. Woman from 50 – 65 are invited to have a smear 5 yearly.
• Benefits and disadvantages According to research 4,500 lives are saved per year.
• Comments Studies are being done to find if HPV testing should be part of screening programme. The results from trials looking at the HPV vaccine have been promising.

Breast

• Current status of screening The screening programme became available nationwide in 1988. The aim is to reduce mortality from breast cancer.
• What the screening programme involves Woman aged 50-70 are invited for a mammogram at 3 yearly intervals.
• Benefits and disadvantages It is thought to save 300 lives per year. The figure is set to rise to 1250 by 2010. For every to million women screened one extra cancer a year after 10 years may be caused by radiation. Possibility of false positive result.
• Comments Women under 50 are not routine screening. Trials are looking at screening for women at higher risk.

Ovarian

• Current status of screening Screening is not currently available. The UKCTOCS trial began in 2001 to find out whether early detection of ovarian cancer will save lives. The PLCO is a large trial in the USA to determine whether certain screening tests will reduce death from cancer. The trial opened in 1993 and enrollment completed in 2001.
• What the screening programme involves 200,000 women will have been randomised to have either ultrasound screening or measurement of CA125. Women were given a trans vaginal scan at initial visit and annually 3 years and or a CA125 test which was taken at initial visit and 5 year annually.
• Benefits and disadvantages This won’t be known until the results of the trial have been published. Of the 28,816 healthy women who had initial baseline screening 4.7% had an abnormal TVU and 402 (1.4%) had an abnormal test. 0.1% had abnormal test results, in both screening tests. Among the women with abnormal test results 29 tumours were detected 20 of which were invasive.
• Comments Results of the UKCTOCS trial are expected in 2012. The results of subsequent years screening is not yet known. Data will continue to be collected 2008

Colorectal

• Current status of screening A pilot study was done in the UK to test the feasibility was carried out.
• What the screening programme involves Screening will be done using faecal occult blood testing. It is for men and women aged between 60 and 69. If the test is positive a colonoscopy will be offered.
• Benefits and disadvantages Cancers detected in the pilot study were 1.62 per 1000 people screened. It is thought that nationally screening for bowel cancer could save approximately 1200 lives each year.
• Comments Funding has been sent to the national screening programmes. The first local screening centre will be in Wolverhampton. It is expected that 14 local screening centres will be operating by March 2007.

Prostate

• Current status of screening Although there has been no organised screening programme an informed choice programme ‘prostate risk management’ has been introduced. The aim is to ensure men who are concerned about the risk of prostate cancer receive clear and balanced information about the benefits and disadvantages of PSA test.
• What the screening programme involves There currently two large international trials looking into prostate cancer, ERSPC and PLCO. Men will be randomised to have either DRE or PSA test.
• Benefits and disadvantages The PSA test could give men reassurance if the test is normal. A rise in PSA may indicate cancer is present before any symptoms are apparent. Test could be false negative and falsely reassure a person.
• Comments The risk of developing prostate cancer is higher in some ethnic group's particularly African Caribbean men. The PROCESS trial is investigating possible reasons for this.