Picking up cancer at a very early stage, or better still before it develops, is hugely important and is why the NHS screens millions of people per year.
Cancer screening
Screening for cancer is vital to detecting cancers early
Screening programs are designed to pick up cancer, or pre-cancerous conditions BEFORE they cause any symptoms. If you have symptoms that you’re worried may be a sign of something serious don’t wait for a screening call – discuss it with your GP. Scientific breakthroughs are always driving changes in how we do things and I thought it would be helpful to explain a little about the three main UK cancer screening programs.
Cervical cancer
Cervical screening is available to anyone aged 25-64, with a cervix. Recalls are every 3 years until age 50, then 5-yearly. It’s estimated that 4,500 lives are saved by cervical screening in the UK annually. Cervical cancer is caused by persistent infection with Human Papiloma Virus (HPV) which is passed by sexual contact. HPV also causes other cancers like anal and mouth cancers. Infection with HPV can irritate cells and cause abnormalities in them. Most HPV infections are transient and slightly abnormal cells often go away on their own when the virus clears. In some people the HPV doesn’t clear and continues to irritate the cells, the changes can then progress and eventually lead to cancer. It takes 15-20 years for cervical cancer to develop in people with normal immune systems which is why there can be long gaps between recalls and screening isn’t started until age 25.
Until recently, cervical screening looked for abnormal cells, but now labs test the samples for HPV, and only if that’s positive do scientists go on and look for abnormal cells. This has really changed the screening process and the NHS is trialling home HPV testing kits - you would then only need to come in and see the nurse if this is positive. If the trial proves successful, this may be the next big change. Another revolution has been the HPV vaccination which started in 2008 with a vaccine for girls age 12-13 against 2 types of HPV (there are around 100 different types, 2 of them are responsible for two-thirds of cervical cancers and 80% of anal cancers, while others cause, for example simple warts and not cancer). In 2018 the vaccination was extended to cover 4 types, and boys are offered it too. The vaccine seems really effective (99%) for a long time (at least 10 years) and is likely to significantly decrease cervical and other cancers in the future.
Bowel cancer
The bowel cancer screening program has been running since 2018. At the moment 60 to 75-year-olds are automatically sent a kit in the post every 2 years, but over 75s can request a kit on the bowel cancer screening helpline on 08007 076060. Over the coming years it’s likely to include people in their 50s too. This program saves more than 2000 lives each year. The small sample of faeces you provide and post back is screened for tiny amounts of blood which can indicate the presence of early cancers and polyps (non-cancerous growths that have a chance of changing to cancer over time). It’s an incredibly easy test and for 98 out of 100 people it’s reassuringly negative, meaning the chance of having a bowel cancer is extremely low. The 2 out of 100 with a positive result, go on to have a colonoscopy and two-thirds of them will have a positive finding of a cancer (often at a very early stage) or a polyp, which can often be effectively treated.
Breast Cancer
Everyone registered with a GP as a woman is invited for a screening mammogram every 3 years from age 50 to 71 (your first call happens any time between 50 and 53). It’s estimated that the breast screening program saves 1300 lives in the UK per year. Like all screening programs it doesn’t find all cancers. There is debate about whether the age of first screening should be lowered, as 20% of breast cancers present before the age of 50, and some countries do screen before 50. A significant reason against lowering the age is that younger people have denser breast tissue, making mammograms less accurate and resulting in missed cancers and overdiagnosis of benign conditions.
Dr Jo Coldron, Tavyside Health Centre, Tavistock