Communicating oral cancer risk due to alcohol

A little while ago I tweeted about a systematic review on alcohol and oral cancer risk that the dental elf had flagged up.

When you ask patients about alcohol intake do you communicate the risk of oral cancer? http://t.co/NUS8frY9GC @thedentalelf
— Dominic Hurst (@Dominic_Hurst) December 4, 2014

But how can be communicate risk in a balanced, non-alarmist, but hopfully behaviour changing way?

In keeping with my previous blog about shared decision-making, patients are entitled to make choices about how they live their lives. In order to do that they may want to have access to some numbers that help them to take a proportionate approach.

In the review of risk of oral cancer the alcohol intake was classified as such:

Light, moderate and heavy drinking was respectively ≤12.5, ≤50 and >50 g per day of alcohol

1 unit of alcohol is the equivalent of 8g, or 10ml, of pure alcohol. (There's a handy guide for those considering their alcohol intake - or wishing to help others to make a change - here. Picture of alcohol units is taken from this)

So roughly the:

• light intake was up to 1.5 units per day
• moderate was up to 6 units 
• heavy was over 6 units per week

The Dental Elf drew attention to the different types of studies included in the review. When only cohort studies were included in the meta-analysis, which are at lower risk of bias, the risk of developing oral cancer was:

• no greater for the light drinkers, 
• about one quarter higher for the moderate drinkers and 
• about 3 times greater for the heavy drinkers. 

The Elf's table reproduced below shows that if case-control studies alone are considered the risks appear much greater. As there is a higher risk of bias in these studies I am inclined to concentrate on the cohort studies alone.

As those of you who are familiar with the work of Gert Gigerenzer, among others, relative risks are not great at communicating risks in a way that allows a proportionate response from a patient yet a lone a clinician.

To say that there is a 3x greater risk of oral cancer if you drink more than 6 units of alcohol a day may sound a lot. But if the lifetime risk of getting oral cancer were, say 1 in 100,000 then having a risk of 3 in 100,000 may not seem terribly significant (assuming there were no other health or social risks to drinking that much).

What we really need to be able to better understand the implications of the increased risk is what the absolute risk of getting oral cancer is.

The closest I could come to this is an overall lifetime cancer risk calculated by the Statistical Information Team at Cancer Research UK. They reckon that 1 in 84 people will develop oral cancer. The number caused by smoking is estimated to be about a half and a third due to alcohol (stats from cancer research). So this number will not be a true reflection of the risk for a non-smoker and non-drinker, which would be expected to be much lower. Can we make use of it though?

My view is that it is not the detailed number that matters when communicating the risk but an indication to a patient of the scale of the impact of their behaviour. So I would recommend making an assumption based on the 1 in 84 figure.

Let's assume that 1/3rd of cancers are caused by alcohol as Cancer Research suggests and that 1/2 are caused by smoking. As a few more are caused by smoking let's assume the average of 1 in 84 is a little lower for drinkers - say 1 in 100. Let's then assume that as about 1/6 of the cancers are in non-drinkers and non-smokers that the lifetime risk in this group is about 1 in 200.

Now we can try to give a sense of the impact of drinking more than 6 units of alcohol by saying:

In non-drinkers we would expect approximately 1 in 200 to get oral cancer. For those who drink more than 6 units per day the number would be 3 in 200.

Now, as we would like to communicate the increased risk for the moderate drinkers of 25% we need to increase the size of the denominator by 4 so that we can say:

In non-drinkers we would expect approximately 4 in 800 to get oral cancer. For those who drink between 1.5 and 6 units a day we'd expect 5 in 800 to get oral cancer. For those who drink more than 6 units a day we'd expect 12 in 800 to get oral cancer.

I hope that this will help communicate oral cancer risk in a balanced way.

Health demotion interventions

Oral health promotion 

I am in the process of writing a piece about how to engage general dental practitioners in oral health promotion drawing on theories and empirical research around how to change professionals' practice. The Ottawa declaration defined health promotion as "the process of enabling people to increase control over, and to improve, their health". The scope of those responsible for health promotion is much broader than just the healthcare system and includes governments, social and educational sectors as well as non-governmental organisations.

However, as a clinician with an interest in promoting evidence-based practice that involves shared decision making I look at the "enabling" and "control" bits with fondness. In my previous blog I discussed the use of decision aids and option grids to try and help convey the risks of good and bad outcomes to patients in ways they are more likely to understand. One of the key findings from the Cochrane review on decision aids found that patients were less likely to opt for invasive procedures when they used one.

Oral health demotion  

As I was thinking about all the health promoting things we would like to be able to do (and be effective at - smoking cessation, sugar reduction, oral hygiene improvement) and how we identify the barriers to doing these things, I had in the back of my mind the problem of things we do that not only don't promote health but actually increase the risk of harm. I thought an apt term for this would be health demotion. The sorts of things I am thinking about are: 

• antibiotic prescribing when there is known to be no benefit (e.g. irreversible pulpitis) that leads to short term side effects and long term resistance that potentially demotes our long term health
• crowns or veneers for cosmetic reasons only on vital teeth that increase the risk of demoting a healthy tooth to a carious, or worse, non-vital tooth

As with health promotion there will not be health demotion in all cases but the risk of this increases. Of course, particularly with the cosmetic treatments, patients have a right to choose a treatment they think may be beneficial but I wonder, if they were given the risks of harm as part of a decision aid, if they might choose the less health demoting route and, by consequence, promote their chance of retaining healthy teeth for a lifetime. If we don't enable patients by communicating evidence in impartial ways they won't be able to take control over their oral health and will be at greater risk of health demotion.

Decision aids and option grids in undergraduate teaching

Communicating evidence to patients

There are always obstacles to using best research evidence with our patients to help them make decisions that are right for them. One of these is the actual conversation and decision-making process we engage in with patients. Assuming we have identified research to help quantify the relative benefits and harms of different treatments how do we communicate these? Given that dentists themselves often struggle to use the data they encounter, what hope is there for our patients?

Integrate evidence into practice

My driving force in the programme of evidence-based dentistry that I have developed and sought to integrate in the 5 year undergraduate dental programme at Queen Mary University of London is that evidence has to be taken beyond critical appraisal and incorporated into the clinical decision-making process. As the students enter their third year and find themselves on clinic, engaging with patients in discussions about treatment options, therefore, seemed like the ideal time in our new curriculum to get them to move their learning about EBD in years one and two onto the clinic.

Shared decision-making

The concept of evidence-based practice for me is one that integrates our own clinical experience, the research and the values of our patients. These are made within a particular context that either facilitates or prevents the use of best evidence (limited resources on the part of patients or the healthcare system will always limit what is actually available). Shared decision making is an approach to care that involves communicating the probabilities of positive and negative outcomes associated with different management options (including doing nothing) (Ref). So how do we communicate the risks and benefits of different treatment options in a relatively objective way?

Decision aids and option grids

There is now quite a large body of research looking at the use of decision aids (Ref) that suggests they can improve several aspects of the decision-making process for patients. From this recent Cochrane review:

"There is high-quality evidence that decision aids compared to usual care improve people's knowledge regarding options, and reduce their decisional conflict related to feeling uninformed and unclear about their personal values. 

There is moderate-quality evidence that decision aids compared to usual care stimulate people to take a more active role in decision making, and improve accurate risk perceptions when probabilities are included in decision aids, compared to not being included.

There is low-quality evidence that decision aids improve congruence between the chosen option and the patient's values."

Engaging undergraduates with decision aids

So we got our third year undergraduates to create their own decision aids relating to various clinical scenarios using the best available research they could. Sometimes this means there was systematic review level evidence to help, for others it was at the level of primary studies. We then had them role play using the decision aids with "patients" (this year it was fellow dental students but we plan to employ actors next year). An example of an option grid (see a brief video describing these below) is here:

The process of using these aids in their discussions with the patients seems to have really caught hold. The ease of use - and confidence it gave them in being able to demonstrate the evidence - were seen as very positive.

We had the students in one seminar not give the decision aids they created to their patients beforehand and in the others they did. By the "patients" reviewing the aids beforehand created a very different dynamic that was led much more by the patients' concerns as they picked up the issues they felt were most important to them and the dental student could then explore these in greater detail.

There is a really nice video showing how option grids (very similar to some decision aids and what most of the students created) can be used here:



What is great is that the day after the seminar students were using their option grids with patients they saw on clinic. Now that's getting evidence into practice!