Abstract
Treatments for cancer can be unpleasant and costly, both for patients and the health service. Preventing cancer is, therefore, beneficial to patients, their families, their communities and the economy. As the population ages, the incidence of cancer is increasing. It is, therefore, important to consider health strategies that combat this situation, including implementation of effective measures to prevent cancer. This article will discuss the preventable risk factors for different cancers and suggest practical, evidence-based ways of addressing risk factors within the time constraints of general practice consultations. In the UK, cancer screening programmes can detect early cancers and some, such as the cervical screening programme, also prevent cancer. It is important to be able to discuss screening with patients and explain the associated benefits and harms.
The GP curriculum and cancer prevention
The role of the GP in the Population health: Promoting health and preventing disease clinical topic guide includes:
An essential role in optimising the public’s health and the health of communities Taking part in health improvement, health protection, and health services Promoting healthy living, delivering screening and immunisation programmes, and using resources and services appropriately Understanding the social determinants of health, from pre-birth to old age Assessing the needs of local population groups Advocating measures that promote good health in populations, as well as individuals Addressing health inequalities Assessing and communicating risk
Relevant emerging issues and knowledge and skills include:
Approaches to behaviour change and their relevance to health promotion and self-care Clinical, social, and environmental risk factors in healthy individuals for a range of common/important conditions (e.g. cancer, heart disease, diabetes, falls) Doctor–patient partnership in conversations relating to self-care
Can cancers be prevented?
Not all cancers are preventable, but sharing information on cancer risk and lifestyle can be an important part of a consultation. Once a cancer develops, spotting the signs and making an early diagnosis can significantly improve treatment options and outcomes, with reductions in mortality and morbidity. Recognising cancer risk, referring appropriately and conveying appropriate information to secondary care is part of everyday general practice. Keeping up-to-date with current evidence and relevant guidelines is essential.
Cancer will affect approximately 1-in-2 people born after 1960 at some point in their lives (Ahmad et al., 2015). Around 4-in-10 cancers are preventable through changes in behaviour (Brown et al., 2018). Smoking is the biggest cause of preventable cancer cases and linked not just to lung cancer, but to at least 14 other cancers, including bladder, bowel, pancreatic and oesophageal cancer. Smoking accounts for 1-in-4 UK cancer deaths (Cancer Research UK (CRUK), 2016a).
The second biggest preventable cause of cancer is being overweight or obese. There is a link between obesity and some of the most common cancers, including breast and bowel, and some of the hardest to treat, such as pancreatic and oesophageal cancer. Government policies to tackle this risk factor at a population level are necessary, including, for example, education in schools and public health measures. However, there is also an important opportunity for GPs to raise awareness of the impact of weight on health with patients and to ensure that baseline weight and body mass index (BMI) are recorded to enable appropriate assessment of risk factors for cancer and other associated diseases such as hypertension and diabetes. Weight is often a sensitive issue, and seeking permission to discuss it is important. The discussion could then include aspects of diet, physical activity, behaviour change and the need for long term follow up as per National Institute for Health and Care Excellence (NICE) guidance (Stegenga et al., 2014). Any intervention should be discussed and agreed with the patient and may include onward referral to tier 2 or 3 weight management services (Stegenga et al., 2014). Other lifestyle adjustments that may reduce the risk of cancer include reducing alcohol consumption, human papilloma virus vaccination, changes in diet, staying safe in the sun and taking regular physical activity. Figure 1 shows the most important lifestyle factors that can reduce cancer risk.
How 4-in-10 cancer cases can be prevented.
Of course, a significant number of cancers are not linked to behavioural factors, and it is wrong to suggest that all cancers can be prevented or that behavioural change will prevent the occurrence of cancer in individual patients. However, the benefits of a healthy lifestyle and healthy behaviours can be effectively promoted by GPs at every opportunity.
Changing patient behaviour through GP consultations
Given that around 4-in-10 cancers can be prevented by behaviour change (Brown et al., 2018) how can GPs encourage behaviour change? There is good evidence for effective intervention with brief advice for smoking cessation. Building on this, very brief advice (VBA) can be a useful tool for GPs. It can be given in 30 seconds or less in routine consultations. The simplest way to give this advice is to say something like: ‘Did you know the best way to stop smoking is with a combination of support and medication – this can be provided here through our smoking cessation advisor’. The important features of this advice are that it is non-confrontational, opportunistic and signposts to the next steps to get support. Some surgeries will not have an in-house smoking cessation service, in which case substitute that for the offer of a suitable, local service.
Ask, Advise, Act: Suggestions for using this model to initiate behaviour change.
Will patients be offended?
Upsetting or offending patients is one of the most common reasons given by GPs for not asking or offering advice about lifestyle factors. However, a study in Oxford found that people considered it appropriate and helpful for GPs to ask about weight (Aveyard et al., 2016). More research is needed on the best ways to approach this subject and NICE guidance suggests using clinical judgement when deciding whether to measure BMI (Stegenga et al., 2014).
Smoking cessation
The strongest evidence for behaviour change intervention with potential for the biggest impact is through smoking cessation. Helping people to stop smoking is one of the single biggest contributions to health improvement that any clinician can make (ASH, 2017). NICE have estimated that £2.37 can be saved on treating smoking-related disease and lost productivity for every £1 invested in smoking cessation treatments (ASH, 2017).
Figure 2 shows that being smoke-free can prevent at least 15 different types of cancer, with lung cancer having the largest numbers of preventable cases. The larger the circle, the larger is the number of cases that are preventable by being smoke-free. Interventions that are effective in helping people to stop smoking include brief advice, behavioural support, prescribed nicotine replacement therapy, Bupropion, Varenicline (Kotz et al., 2014) and e-cigarettes (Brown et al., 2014). It is worthy of note that over-the-counter nicotine replacement alone, without additional behavioural support is no more effective than going cold turkey (Kotz et al., 2014). See Box 1 for further resources related to smoking cessation.
Being smoke-free can prevent 15 types of cancer. Further resources.
E-cigarettes
The most effective way to quit smoking is a combination of medication and support, and this should be the first approach. However, more patients are asking about e-cigarettes as an alternative to smoking or as a smoking cessation aid. E-cigarettes are now the most popular tool for quitting smoking in England (smokinginengland, 2018). There is not yet enough evidence on the safety of e-cigarettes, but they are certainly not risk-free. There is, however, plenty of evidence that they are far less harmful than smoking. The evidence so far suggests that concerns about e-cigarettes being an entry point to smoking are unfounded (CRUK, 2016b). The RCGP has a position statement, supported with a video and podcast, which makes this point, and suggests that primary care professionals recommend e-cigarettes to patients as an option for smoking cessation using individual clinical judgement on when this is appropriate (RCGP, 2017).
Cancer screening
There are currently three cancer screening programmes in the UK. These are aimed at breast, bowel, and cervical cancers. Screening looks at a population and works a bit like a filter to identify those who are at higher risk of a disease. Those who screen as higher risk are then offered further investigations to determine whether or not they have the disease. Screening at a population level is beneficial, as it can help detect cancers at an early stage, when treatment is more likely to be successful, and in some cases help prevent cancer developing in the first place. There is an important role for GPs to advise patients on the pros and cons of screening and on abnormal screening results, which they often choose to discuss with their GP.
It is important to remember that there are harms, as well as benefits, from screening programmes. There is inevitably a false positive rate with any screening test and this may cause significant anxiety, particularly when further investigations are needed. Careful explanation is essential and patients advised to return to the screening programme.
Breast cancer
Screening for breast cancer is primarily with mammography to detect pre-symptomatic disease. Women in the UK are eligible for screening between 50 and 70 years of age (some areas screen slightly younger women from age 47 years). Over the age of 70 years, women can request further screening, but are not invited routinely. It is important to be aware that there are separate NICE guidelines for screening in women who are at moderate or high risk of breast cancer and these women may be eligible for more frequent screening, screening outside the usual age window or using different tests (NICE 2013).
Bowel cancer
Across the UK, bowel cancer screening is in transition from faecal occult blood testing to the faecal immunological test (FIT). The FIT is more specific for blood in the stools and associated with a higher uptake, probably because it is simpler and only requires a single stool sample. The FIT detects human globin, not all haemoglobin. These screening tests are designed to detect early cancers before symptoms develop. There is good evidence, particularly in bowel screening, that GP endorsement of the test within the screening invitation letter increases uptake (CRUK, 2017). Contacting non-attenders or reminding patients opportunistically during consultations is also effective.
Cervical cancer
Cervical screening is offered to all women and people with a cervix aged between 25 and 64 years; it detects pre-cancerous changes that can then be treated, thereby preventing the development of cancer. Cervical samples are also tested for the presence of human papilloma virus (HPV) which increases the risk of developing cervical cancer. As most cases of cervical cancer are caused by HPV, primary testing for HPV is being introduced by the NHS. Cytology will then follow each positive result for HPV.
The switch to HPV primary testing was made in Wales in September 2018, with England due to follow by the end of 2019 and Scotland in January 2020. No such decision has been made at the time of writing on cervical screening in Northern Ireland.
There is now a programme of routine vaccination for HPV, and this also has a role in cancer prevention. Since 2008, females aged between 11 and 13 years have been offered vaccination against the two most common ‘high-risk’ types of HPV (CRUK, 2018). These are HPV 16 and 18. Together, these two types cause about 7-out-of-10 cervical cancers (CRUK, 2018). Girls up to the age of 18 years can request vaccination through the NHS if they have not had it previously. As the HPV vaccine only protects against some types of HPV, screening is still important for those who have been vaccinated. From September 2019 all 12- and 13-year olds in school year 8 have been offered HPV vaccination.
The importance of early diagnosis
Early diagnosis of cancer can improve prognosis. Screening can achieve early diagnosis, but awareness of possible symptoms of cancer also informs referral according to referral guidelines for suspected cancer (NICE, 2015) and the Scottish cancer referral guidelines (NHS Scotland, 2015). Although prevention is better than cure, cure is easier, cheaper and more likely to be effective with early diagnosis.
In England, the current NICE guidance sets a threshold for referral for cancer risk at 3%, based on the combination of symptoms, signs and results of basic investigations (NICE, 2015). This is a lower threshold than in earlier guidance, and lowering the threshold was intended to increase early referrals and earlier-stage diagnosis of disease.
Of course, clinical judgement should also be used when deciding to refer or not. For GPs a ‘gut feeling’ about a patient and their presentation is important and should not be ignored when making decisions about referral. See Box 1 for further resources related to early diagnosis.
Secondary prevention
As cancer survival increases, it is more common for people to live with a first cancer diagnosis and to then develop a second and even a third cancer. Those living with and beyond cancer should continue to have access to advice on cancer prevention, including on smoking cessation, maintaining a normal weight, reducing alcohol consumption, maintaining good levels of physical activity and staying safe in the sun. Apart from sun exposure, these are also risk factors for other significant medical conditions. As part of their cancer treatment many people will be offered a wellbeing event, in which many of these messages are discussed and explained. When seeing a patient for a cancer care review or opportunistically after a cancer diagnosis, do not forget that prevention still matters.
KEY POINTS
Around 4-in-10 cancers are preventable largely through behaviour change Overweight and obesity are the second biggest preventable cause of cancer There is good evidence for brief advice in helping trigger a change in behaviour E-cigarettes are much less harmful than smoking Behaviour change advice, screening and early diagnosis all have important roles in improving cancer outcomes A positive predictive value of 3% is the NICE guidance threshold for referral on to a suspected cancer pathway
