Genetic test to stop smoking (GeTSS) trial protocol: randomised controlled trial of a genetic test (Respiragene) and Auckland formula to assess lung cancer risk
© Nichols et al.; licensee BioMed Central Ltd. 2014
Received: 27 September 2013
Accepted: 26 March 2014
Published: 1 May 2014
A gene-based estimate of lung cancer risk in smokers has been shown to act as a smoking cessation motivator in hospital recruited subjects. The objective of this trial is to determine if this motivator is as effective in subjects recruited from an NHS primary care unit.
Subjects will be recruited by mailings using smoking entries on the GP electronic data-base (total practice population = 32,048) to identify smokers who may want to quit. Smoking cessation clinics based on medical centre premises will run for eight weeks. Clinics will be randomised to have the gene-based test for estimation of lung cancer risk or to act as controls groups. The primary endpoint will be smoking cessation at eight weeks and six months. Secondary outcomes will include ranking of the gene-based test with other smoking cessation motivators.
The results will inform as to whether the gene-based test is both effective as motivator and acceptable to subjects recruited from primary care.
Registered with Clinical Trials.gov, Registration number: NCT01176383.
KeywordsSmoking cessation Genetic test Lung cancer
Gene testing in primary care is no longer limited by their exorbitant cost. The prices of genetic tests are dropping faster than Moore’s law for computing costs . This leads the focus to shift from cost of genetic testing to the clinical value of individual gene tests. The recent development of gene-based tests that predicts the risk of lung cancer in smokers is an important example .
Respiragene study in Auckland NZ (n = 43)
Cancer susceptibility scale (compared with normal lifetime risk)
Cancer susceptibility score
Estimated lifetime risk of lung cancer
Initial intention to quit
Proportion that stopped smoking at 2-4 weeks
Proportion still not smoking at 6 months
Expected result for telephone counselling (Figure 2)
Telephone counselling + Respiragene test
1-2.3 (10-35% risk) 2.3-6.7 (35-65% risk) 6.7-8 (65%-80% risk)
27 had average risk score
16 had high or very high risk score
30-50% (4-10 times average risk)
A large hospital trial using Respiragene for calculating lung cancer susceptibility is currently underway in the USA , but there are no planned UK investigations. This study fills that gap and uses the NHS framework for smoking cessation. Other studies have taken place looking at how lung functioning testing in COPD might motivate smokers to quit, suggesting that it is feasible to conduct this sort of study [13, 14, 20]. This protocol describes a trial to evaluate a gene-based risk test (using genetic and clinical data) as a smoking cessation motivator, in smokers wishing to participate in an NHS primary care smoking cessation clinic (in the action stage of change), alongside the usual counselling and prescribing protocol. It will differ from previous studies using gene testing as a motivator, however, in that the NHS primary care counselling and prescribing protocol will include several other motivators (CO breath testing, saliva cotinine testing and intensive counselling) whereas the Auckland trial, using the same gene test, had none of these. Also, the method of recruitment will differ in that primary care subjects will, of necessity, be different from the Auckland hospital outpatient cohort [15, 16].
Can the Respiragene test combined with an estimation of lung cancer susceptibility be used to increase the uptake, adherence to and success rate in an established smoking cessation programme in subjects who want to quit in a National Health Service, United Kingdom (NHS UK) setting?
Genetic testing and estimation of lung cancer susceptibility should increase “smoking cessation outcomes” at six months to >30% (or 1.5-2 fold greater than usual care) irrespective of the risk scores assigned to subjects .
This protocol has been approved by Surrey Research Ethics Committee at the Royal Surrey County Hospital, Guildford, Surrey, UK.
A number of focus groups of different aged smokers will be held to enable them to contribute to the design of the study
Mailing 2. The principal investigator mails patient with Letter 2 to ask him/her if they would like to attend an 8-week smoking cessation clinic and asks if they would be willing to have a test for genetic susceptibility to development of lung cancer and encloses SAE for reply.
Mailing 3. The principal investigator mails Group B subjects and Group A test-concordant subjects to confirm dates of the smoking cessation sessions and full patient information leaflet and consent form enclosed. The information sheet will be slightly different for group A and B. Non-test concordant subjects within group A will be invited to attend the practice nurse for smoking cessation.
3/Inclusion and exclusion criteria
Inclusion criteria: Aged 20-70 years, smoking more than 10 cigarettes daily.
Exclusion criteria: Aged under 20 years or over 70 years, smoking less than 10 cigarettes daily, history of major depression and other psychiatric conditions, dementias and serious or terminal illness (cancers etc.). Patients on warfarin would be excluded due to interactions between warfarin and varenicline as varenicline will be used as the modern treatment of choice for smoking cessation. Patients who smoke less than 10 cigarettes/day and patients who did not wish to have a genetic test or do not wish to take part in a research study will be referred to the practice nurse for smoking cessation.
4/Smoking cessation clinics
For group A subjects, only subjects who have expressed an interest in having a genetic test and gene-based estimation of susceptibility to lung cancer in mailing 2 will be invited to participate (see referral for decliners above). For group B subjects, all subjects willing to participate are invited to do so. Uptake into smoking cessation programme (i.e. proportion of invitees who accept invitation and attend clinic of those mailed invitation) will be recorded. All subjects who attend the first session of the research clinic will be asked by the principal investigator, JN, to sign a consent form and will be invited to raise any concerns about the protocol (as explained in the full information sheet). The consent form will then be countersigned by JN.
Group A clinics and Group B clinics will be held on different weekdays at the same health centre premises.
Test Subjects who attend Clinic A will be offered a fact sheet on the health risks of smoking (including lung cancer) and the option of the gene-based test for calculation of lung cancer susceptibility whilst subjects who attend Clinic B will be given the same fact sheet on the health risks of smoking (including lung cancer) but without any reference to the gene-based test. The principal investigator will be responsible for handing out the fact sheets and administering the gene-based test in Clinic A and for handing out and explaining the fact sheet in Clinic B.
NHS Surrey’s Smoking Cessation Practitioners will lead in-house smoking cessation clinics A and B using the NHS smoking cessation guidelines  under the supervision of the principal investigator at the medical centre. There will be:
Introductory session which includes a new near patient test for salivary cotinine (nicotine metabolite) – trade name SmokeScreen .
At session 2, patients will be given advice on therapies for smoking cessation. We expect that most patients will opt for a course of varenicline and they will be advised to contact their GP for a prescription.
This is followed by seven more weekly sessions and a follow-up session at six months (Figure 4). Uptake and adherence to smoking cessation will be monitored by weekly carbon monoxide exhalation measurements (breath test). The principal investigator will be involved in clinic A administering the gene-based test and determining if subjects have COPD from practice records and history in session 1. Participants who are heavy smokers, have a smokers cough and use a salbutamol inhaler can be judged to have COPD even if this is not entered in their GP records (all Group A & B subjects will have spirometry at their 6-month follow-up). Subsequently the principal investigator will report back to clinic A patients with estimated lung cancer risks (session 3). To ensure balance in the control clinic the principal investigator will also attend Clinic B sessions 2 and 3 (see Figure 5 flow charts).
At the eight week clinic and the 6-month follow-up clinic smoking cessation status and carbon monoxide breath test score will be recorded and a feedback questionnaire used to assess efficacy of various components will be administered.
for further details see Figure 5: flow charts
We anticipate good attendance at the eight week free smoking cessation clinic, as would be expected if it were a regular NHS smoking cessation clinic but the attendance at the 6-month follow-up clinic may be more challenging. We consider this attendance essential and as attendance will take up an evening of their time, study participants should be paid for their travel expenses (£20) and will receive up to three reminders. Group B subjects attending at the 6-month follow up who have been unable to quit will be offered the gene-based test at this stage.
Technique for taking the respiragene test
Open buccal swab package at the handle end and carefully remove the swab.
Holding handle end of swab stick, scrape the collection tip firmly against the inside of the cheek 5-6 times (about 10 seconds), being careful not to press the plunger that ejects the tip.
After taking the sample, eject the swab tip into a labelled 2 ml microcentrifuge tube by firmly pressing the plunger at the end of the handle.
Complete and affix the sample tube label onto the microtube. The sample label requires the anonymised trial code for the subject.
Storage of the respiragene test
After sample collection, tips can be kept at room temperature if they are posted immediately. If storage is necessary, freeze the tubes containing the tips at -20°C.
Packaging instructions for return of samples to Lab21 Ltd
Place absorbent material around the tube and then place tube in the plastic bag provided with the kit. Seal the plastic back as per the instructions on the bag
Place the plastic bag containing the sample tube into the shipping box.
Seal the box with the security seal supplied.
Using the Freepost service provided, send the samples to: Lab 21, 184 Cambridge Science Park, Cambridge CB4 0GA.
Patients will be asked to sign a disclaimer form that explains clearly that this test can only give an estimation of cancer risk and is a test that is still under development (one copy of form for investigators and one for patient).
Interpretation of result of respiragene test
Lung cancer susceptibility is calculated using the Respiragene test Auckland formula :
Lung cancer score = (number of susceptible genotypes) - (number of protective genotypes) + 3 (for positive family history) + 4 (for past history of COPD) + 4 (for age > 60 years old).
The laboratory reports include the scores with an explanation of how the scores relate to a risk category (see Table 1). When the subject is aged <60 years, the report will also include the score and risk category that would apply if the subject is still a smoker at age 60 years or over.
The questionnaires will be slightly different for groups A (questionnaire 2a) and B (questionnaire 2b) as only 2a will contain a direct reference to the gene-based test. Patients who fail to attend at eight weeks and six months will be contacted by telephone to remind them to complete their questionnaires and hand them in to the practice manager. They are designed to determine which subjects have quit smoking or cut down and which subjects who have failed to quit still plan to do so. There is a section that asks about general motivators and components of the smoking cessation programme. The subjects will be asked to score these motivators and smoking cessation aids for their efficacy in helping them to quit. The questions in this section are almost identical to a validated questionnaire . There are also further questions on whether the subject would recommend the Respiragene test to a relative or friend and an open ended question for subjects to add their own comments about the concept of a test that predicts susceptibility to lung cancer in a smoker.
Data quality assurance
The study has been designed and will be reported in accordance with CONSORT (Consolidated Statement of Reporting Trials) . Data will be controlled in accordance with data protection legislation, institutional protocols of Sussex NHS Research Consortium, and NHS policies for research and information governance for ensuring patient confidentiality . Data will be analysed in SPSS (Statistical Package for Social Sciences) version 15 using an intention to treat approach.
Comparison of smoking cessation rates (7 day point abstinence and continuous abstinence) in Clinic A and Clinic B at 8 weeks and six months.
Number of smokers still smoking who state that they still plan to stop.
Daily cigarette consumption of those still smoking.
Mean scores for ranking of smoking cessation aids (gene-based test - Clinic A only, salivary cotinine, lung cancer facts - controls in Clinic B only and general counselling from NHS smoking counsellors).
Analyse questions about whether subjects would recommend the test to a member of family or a friend.
Analyse last (open ended) question using qualitative research methodology.
Primary end point
The difference between smoking cessation between Clinic A and Clinic B will be estimated from the four week and six month follow up for the primary endpoint (smoking status confirmed by carbon monoxide breathalyser and salivary cotinine tests). If there is the expected higher rate of smoking cessation for Clinic A compared with Clinic B, statistical significance will be demonstrated by the χ2 test.
Since there are, as yet, no case-control studies that compare quit rate following the gene-based test versus quit rate without the test, the expected difference in quit rate between Clinic A and Clinic B is difficult to estimate. Two case-control studies showing only a 5-10% increase in smoking cessation involved just a single gene of small effect [11, 12]. In a randomised control trial patients were given either a full explanation of the results of spirometry testing, including an estimation of lung age or just the FEV1, without explanation (control group). The group of patients who were given the full explanation had a 7.2% higher quit rate than the control group. However, data from Auckland suggest a larger uplift of quit rate with Respiragene. This can be explained by the superior predictive power of a 20-gene test combined with clinical history (personal history of COPD and family history of lung cancer) to give a rather more impressive estimate of cancer risk than anything previously available.
The adequacy of sample size was tested using data from smoking cessation trials that showed:
A 48% quit rate at 2-4 weeks in subjects with high and very high lung cancer risk scores but this difference shrinks to 27% at 6 months.
Summary of values from which the power of the study are estimated
Control group expected quit rate as %ge
Respiragenegroup expected quit rate as %ge
χ2calculated from four-some table
P value based on χ2
Sample size 30/30*
Sample size 60/60*
Sample size 30/30**
Sample size 60/60**
Secondary outcome measures
Similarly, the significance of secondary endpoints on intention to stop smoking, cigarette consumption, uptake of invitation to cessation, adherence to cessation course and self-reported smoking cessation will be calculated by the χ2 test but the p value for the ranking scores for information on lung cancer risk and other smoking cessation aids and motivators will be estimated from the unpaired student t-test.
The open ended question: “How do you feel now about having had a genetic test that estimates the probability that you will develop lung cancer at some future date?” will have to be analysed by qualitative analysis to determine the main recurrent themes in responses.
Smoking cessation is one of the most cost effective interventions that can be achieved in primary care . However many smokers are very reluctant to commit to a smoking cessation programme (precontemplative and contemplative) and about half of those that attend for smoking cessation intervention (action stage of change) are likely to drop out or give up trying. Therefore, any methodology that increases motivation in both unmotivated and motivated smokers could be very valuable. The gene-based test we are offering has shown promise as a smoking cessation motivator in precontemplative-contemplative smokers in a hospital outpatient setting [15, 18] and now needs to be tested out as a motivator for improving adherence in a primary care smoking cessation clinic using a randomised controlled study.
The main strengths of this study are that it is being carried out on subjects from a large primary care population and should therefore be more representative of the general population than previous studies recruited from hospital patients and other special groups. We also have the advantage of being able to carry out this research within the established framework of the local stop smoking service.
Limitations and assumptions
Although we have estimated, based on previous smoking cessation work using this gene-based test, that the primary endpoint will show that having the test improves quit rate by 20-25%, this was based on a cohort of hospital outpatients in Auckland, New Zealand and subjects recruited from primary care may respond differently. Although we plan to recruit a minimum of 60 subjects, this may not be enough to balance unexpected and unknown confounding factors.
What we might find
We aim to recruit a minimum of 60 subjects to randomise 30 into group A (test group) and 30 into Group B (control group). The normal experience in NHS smoking cessation clinics is a drop-out rate of 40-50% [30–32]. We need, therefore, to attempt to recruit about 120 subjects in order to get a statistically significant result, based on the assumptions in our power calculations. We may, however, have underestimated the 6-month quit rate using the NHS local stop smoking guidelines  which typically involves a multi-interventional programme which includes combinations of varenicline prescriptions, breath carbon monoxide monitoring and intensive counselling giving a quit rate of 70-80% at 6-weeks.There are however no Surrey data for 6-month quit rate which we assume, on the basis of similar smoking cessation data to be about half the 6-week figure  ≅ 35%.
An unknown and unpredictable factor, that could skew results significantly, is the possibility that our multi-interventional approach could help to reinforce the health risk message equally for subjects in both groups. Also, the Auckland study design involved recruitment of precontemplative-contemplative smokers from a hospital outpatient setting, compared to this study that will involve primary care subjects who have volunteered to participate in a smoking cessation programme (ie smokers in the action stage of quitting). This population, therefore, could be sufficiently different to give unexpected results. However, the results of this trial will inform as to the acceptability of this approach as well as its effectiveness.
PG is a Visiting Professor of Primary Care at The University of Surrey. SdeL is Professor of Health Care and Clinical Informatics at The University of Surrey. JN is a primary care physician and visiting research fellow at The University of Surrey. WK is a visiting research fellow at The University of Surrey and an experienced smoking cessation nurse. PW is a Statistics Consultant in the Department of Mathematics at The University of Surrey.
Consolidated statement of reporting trials
Chronic obstructive pulmonary disease
National health service UK
Single nucleotide polymorphism
Stamped addresses envelope.
We are grateful for the help of Aino Telaranta-Keerie and the staff of Lab 21 for their support and for carrying out the Respiragene tests. We are also indebted to Kevin Murphy of Synergenz for his encouragement and support. Professor Robert Young, and his team, of Auckland, New Zealand developed the Respiragene test and the risk score formula. His advice and guidance has been invaluable.
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