Screening for Cancer

Published: 17 October 2023

In this blog, Dr Anthony Cunliffe discusses screening for cancer as one of the most important ways in which cancer can be diagnosed at an early stage when there are more options for curative treatment.

Dr Anthony Cunliffe

Dr Anthony Cunliffe Part-time GP, joint clinical director of South East London Cancer Alliance; National Lead Medical Advisor and Clinical Adviser for London Macmillan Centre of Clinical Expertise

Screening for cancer is one of the most important ways in which cancer can be diagnosed at an early stage when there are more options for curative treatment and therefore better outcomes. In the UK there are 3 national cancer screening programmes in place for cervical, colorectal and breast cancers which are offered to people who meet certain sex and age criteria and at specific time intervals. Screening can diagnose cancer early because, by definition, it is testing for a condition before symptoms appear. For example, one year survival for bowel cancer detected through screening is 97%, but through emergency presentation it is only 49%. The cancer screening programmes for cervical and bowel have the additional benefit of being able to prevent cancer from developing in the first place by detecting and treating changes that could lead to cancer, if left untreated.


Unfortunately, in the UK, uptake to the screening programmes is very variable with less than 50% of people choosing to engage with some of the cancer screening tests in some areas of the UK.


Engagement with cancer screening is even lower in certain under-served or marginalised populations including ethnically diverse groups, people living in areas of social deprivation and those with learning disabilities. For some population groups, the general information received may not be useful, as it may not be in their first spoken language or  be culturally sensitive, automatically creating a barrier to them accessing the programme and impacting their opportunity to engage with what can, for some, be a lifesaving intervention. Meanwhile, other groups may be disadvantaged by practical difficulties in attending a screening appointment or even, as we know to be the experience of some people within the LGBTQIA+ community, not receiving the relevant invite in the first place due to potential lack of understanding by individuals or healthcare professionals, as to whether or not they are at risk. 


A decision whether to engage with a screening test is of course, an individual decision. Common barriers that prevent people engaging with screening programmes include lack of time, lack of appropriate access, fear of results, lack of understanding or even the cost of attending an appointment. 


However, it is important, that when offered a cancer screening, people fully understand the intention and benefits of the tests and  are making a truly informed decision whether to engage or not. As health care professionals we have an important role in ensuring our patients are fully informed to make the right decisions for them, as well as helping them overcome  any barriers they may face.

Bowel screening

The National Bowel Cancer screening programme offers testing to everyone between the ages of 60-74, with roll out to earlier ages happening in some areas of the UK. There is significant geographical variation in this screening programme with some regions having significantly less than half of those offered the test actually taking it up.


A test, called a Faecal Immunochemical Test (FIT), is sent out in the post every two years which requires a sample of stool to be collected and returned which is then assessed for the presence of blood and, if present above a specified amount, leads to an invitation for a more detailed test, usually a colonoscopy.


The chances of someone with a positive FIT test via the screening programme having cancer is between 8-10% so a positive test doesn’t mean someone has cancer but does lead to further tests that can either confirm a diagnosis, potentially at an early stage, or identify pre-cancerous lesions that can be removed and help prevent development of cancer in the future. This latter point is really important in communicating to people the benefits of bowel cancer screening. Further information can be found on the bowel cancer information page.

Cervical screening

Although the process of taking a cervical sample may detect a cancer, the purpose of the screening programme is to detect the Human Papilloma Virus (HPV) and so greatly reduce the chance for cancer to develop at all. In England and Northern Ireland, cervical screening is offered to women between the ages of 25 - 49 every three years and to women aged between 50 - 64 every five years. In Wales and Scotland invites are sent out every five years between the ages of 25 and 64. 


The process of cervical screening involves taking a sample of cells from the cervix using a soft brush (often referred to as a ‘smear’), most often done by a Nurse or GP, which is then sent to a lab to be tested. Some strains of HPV can cause cervical cells to become abnormal, with the vast majority of cervical cancers caused by HPV. Currently in Northern Ireland the process is slightly different and checks are done to identify changes in cervical cells before subsequently checking for HPV. Cervical screening should be offered to all people with a cervix, and this includes trans and non-binary people, who often experience inequalities in accessing screening programmes.


As with the other screening programmes, uptake can vary with people having specific reasons for declining the test, including, among others, embarrassment, pain and trauma but it is vital that everyone has access to the information that is right for them so they can make an informed decision. For example, some groups find it particularly difficult to engage with cervical screening due to practical reasons such as people with physical disabilities and it is important that services make necessary adjustments to support these individuals.  All people eligible for screening should be supported to engage, and signposted to useful resources such as My Cervix My Service or Clinic Q. Further information and support can also be found on the cervical screening webpage.


A vaccination programme to prevent the development of HPV and thus potentially prevent cervical cancer is available across the UK, offered to everyone, regardless of sex from the age of 12. The vaccine can also contribute to the prevention of other cancers including anal cancer and some head and neck cancers. People with a cervix can access the vaccine up to the age of 25 if they weren’t vaccinated earlier, and men who have sex with men can access it up to the age of 45 via sexual health clinics.


Breast screening

Anyone in the UK who is registered with a GP as female should receive an invite to a mammogram, a form of x-ray, every 3 years starting from the age of 50 until age 71. Over the age of 71, eligible individuals can opt in to continued testing but this requires them to contact their local breast screening service. It is important for health care professionals to be aware of this opt-in service and to support patients who do wish to continue with screening to do so. 

The aim is to detect breast cancer early before any symptoms or signs have been noticed but this programme doesn’t have an element of prevention as the other cancer screening programmes do. If an abnormality is detected, then further, more detailed tests will be carried out and, although not everyone with a positive mammogram will have cancer, the process can still lead to significant anxiety. Some cancers picked up by breast screening may, potentially, never have caused any problems but, once diagnosed, will in most cases lead to the patient having treatment. This is often referred to as ‘overdiagnosis’ and ‘over treatment’ but any decisions regarding treatment for cancers diagnosed will be supported by specialists who have a robust understanding of this issue.

Those who have a strong family history of breast cancer or a known gene mutation may be offered screening from an earlier age. As with the other screening programmes there are resources to support under-represented or marginalised groups to access breast screening including for those with learning disabilities. As with cervical screening, there is a risk that trans individuals may not be offered screening when it is appropriate. Trans men who have not had a mastectomy and trans women who have taken feminising hormones should all be invited for breast screening. 

While it is evident that screening programmes play a vital role in helping to detect cancer earlier or even mitigate the risk of cancer developing in some cases, inconsistent understanding and availability of information are key factors that are leading to inequitable access and uptake of screening. As healthcare professionals, we all have the responsibility to ensure better inclusive practice around screening.

This is how Macmillan can help your patients

We also understand that waiting for tests and diagnosis can be a very stressful time for patients, and they may have a lot of questions. There is a lot of information you can signpost patients to around going for tests and waiting for results.

Our freephone support line is also a great place to signpost patients to, as they are open every day and are able to offer confidential support to patients and their loved ones.