Introduction
Preface
Purpose of the study and analyses
Study aims and outcome measures
Aims
Primary
Secondary
Outcome measures
Primary outcome measure
Secondary outcome measures
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Was this usually a high-protection sunscreen (SPF 30 or more)? (yes/no)
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How often on average have you used sunscreen in the past month? (less than once a week, 1–2 days a week, 3–5 days a week, 6–7 days a week)
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On days that you have used sunscreen in the past month, how often did you apply it? (open response restricted to numbers)
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Did you usually apply sunscreen (select one of the following): to all parts of your body exposed to the sun OR only to parts of your body that are prone to sunburn.
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I believe that melanoma is easy to cure
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I believe that melanoma can have very severe consequences
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Getting melanoma would be a big health threat for me
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It is important to check my skin for skin cancer even if I have no symptoms
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Checking my skin regularly is a priority for me
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I think I could find something suspicious on my skin if it was there
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If I saw something suspicious on my skin, I’d go to the physician straight away
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I am confident in a physician’s ability to diagnose skin cancer
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I am confident that I can take up examining my own skin even if I have not looked at my skin the past few months
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I am able to examine my own skin regularly, even if I have no one to help me
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If I regularly examine my skin, then I am helping to look after my own health
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I feel more healthy with a suntan
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A suntan makes me feel better about myself
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A suntan makes me feel more attractive to others
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This summer I intend to sunbathe regularly to get a suntan
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Most of my close family think that a suntan is a good thing
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Most of my friends think a suntan is a good thing
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A suntan protects you against melanoma and other skin cancers
Psychological outcomes
Distress (6 items) | Feeling upset about my risk information |
Feeling sad about my risk information | |
Feeling anxious or nervous about my risk information | |
Feeling guilty about my risk information | |
Feeling a loss of control | |
Having problems enjoying life because of my risk information | |
Uncertainty (9 items) | Worrying about my risk of getting cancer (or getting cancer again if you have already been diagnosed with cancer) |
Being uncertain about what my risk information means about my cancer risk | |
Being uncertain about what my risk information means for my child(ren) and/or family’s cancer risk | |
Having difficulty making decisions about cancer screening or prevention (e.g. having preventive surgery or getting medical tests done) | |
Feeling frustrated that there are no definite cancer prevention guidelines for me | |
Thinking about my risk information has affected my work or family life | |
Feeling concerned about how my risk information will affect my insurance status | |
Having difficulty talking about my risk information with family members | |
Worrying that the genetic counselling and testing process has brought about conflict within my family | |
Positive experiences (4 items – reverse scaled) | Feeling relieved about my risk information |
Feeling happy about my risk information | |
Feeling that my family has been supportive during the genetic counselling and testing process | |
Feeling satisfied with family communication about my genetic risk information |
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I felt I could talk about my reaction to my risk information with the genetic counsellor
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The genetic counsellor helped me to understand my risk information and make decisions about my health care
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I felt better about my health after talking to the genetic counsellor
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The length of the phone call was appropriate
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The genetic counsellor was truly concerned about my well being
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Talking to the genetic counsellor was valuable to me
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Understanding of genetic risk information, and amount read by participants
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Recall of personal genetic risk category
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Communication of result with family, friends and health professionals
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Motivations and barriers to family communication about genetic risk [33]
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Satisfaction, understanding and amount read of the personal genetic risk booklet
Methods
General study design and plan
Eligibility criteria
Randomisation and blinding
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Traditional phenotypic risk score (low vs. high) [36],
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Sex (male vs. female),
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State or territory of residence within Australia, and
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Age group (18–44 years vs. 45–69 years)
Study variables
Study period | |||||
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Screening/consent | Baseline/randomisation | Intervention delivery | Follow-upa | ||
Time point | -1 | 0 | T1 | F1 | F2 |
Enrolment: | |||||
Eligibility screen | X | ||||
Informed consent | X | ||||
Allocation | X | ||||
Group allocation: | |||||
Intervention arm: | |||||
Saliva sample | X | ||||
Personalised melanoma genetic risk booklet | X | ||||
Phone call from genetic counsellor | X | ||||
Educational booklet on melanoma preventive behaviours | X | ||||
Control arm: | |||||
Educational booklet on melanoma preventive behaviours | X | ||||
Assessments (control and intervention patients): | |||||
Demographics | X | ||||
Melanoma risk factors | X | ||||
Sun exposure (objective measure) | X | Xb | X | ||
Sun exposure (self-report) | X | X | X | ||
Sun-protection behaviours | X | X | X | ||
Skin examination behaviours | X | X | X | ||
Intentions, beliefs and attitudes towards sun-protection behaviours and skin examinations | X | X | X | ||
Discussion about sun protection and skin examinations with family | X | X | X | ||
Perceived social norms about sun protection and skin examination | X | ||||
Perceived melanoma risk | X | X | X | ||
Skin-cancer related worry | X | X | X | ||
Perceived control over the development and early detection of future melanomas | X | X | X | ||
Risk taking behaviours (Domain-Specific Risk-taking scale (DOSPERT)) | X | ||||
Psychological distress and well-being (MHI-5) | X | X | X | ||
Confidence in completing medical forms | X | ||||
General health | X | ||||
Satisfaction with educational booklet on melanoma preventive behaviours, and amount read by participants | X | X | |||
Out-of-pocket costs for sun-protection items | X | X | |||
Visits to health care professionals | X | X | |||
Private health insurance | X | X | |||
Use of medications that may increase risk of melanoma or skin sensitivity to sunlight | X | X | X | ||
Importance of health | X | ||||
Confidence in understanding medical information | X | ||||
Reasons for participating in the study | X | ||||
Receiving advice from health professional regarding sun protection and skin checks | X | X | X | ||
Information seeking about skin cancer and genetics | X | X | X | ||
Use of the study website | X | X | X | ||
Use of applications related to sun protection or skin examinations | X | ||||
Measures related to receiving genetic risk information (intervention participants only): | |||||
Recalling personal genetic risk | X | X | |||
Communication with family, friends and health professionals about genetic risk | X | X | |||
Motivation and barriers to communication about genetic risk | X | X | |||
Satisfaction with genetic risk booklet and genetic counselling | X | X | |||
Understanding of genetic risk information, and amount read by participants | X | X | |||
Multidimensional impact of cancer risk assessment | X | X |
Sample size
General considerations for statistical analysis
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All analyses will be conducted on an intention-to treat basis. All randomised participants will be analysed in the group to which they were assigned
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The primary analyses will stratify by phenotypic risk category (high, low)
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Statistical hypothesis tests will be evaluated at a nominal two-sided 5% level of significance
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Intervention effect estimates (i.e. difference in means, odds ratio or relative risk) and their 95% confidence interval (CI) will be reported for all outcomes
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The assessment of the overall intervention effect on outcome measures will be adjusted for baseline scores and randomised stratification factors
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Subgroup analyses will be carried out irrespective of whether there is a significant effect of intervention on outcome
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P values will not be adjusted for multiple comparisons.
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P values will be reported to three decimal places unless the P value is less than 0.001, in which case it will be reported as ‘ < 0.001’. The mean, standard deviation (SD) and any other statistics other than quantiles will be reported to one decimal place greater than the original data. Quantiles, such as median, or minimum and maximum will use the same number of decimal places as the original data. Estimated parameters, not on the same scale as raw observations (e.g. regression coefficients), will be reported to three significant figures
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Analyses will be conducted primarily using SAS, version 9.4 or later and R 3.6.1 or later
Timing of analyses
Analysis populations
Covariates and subgroups
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Sex: male/other vs. female
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Age: 18–44 vs. 45–69 years
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State or territory of residence (based on latitude): QLD, NT, WA, NSW, ACT vs. SA, VIC, TAS
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Health literacy and numeracy: higher vs. lower [28]
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Family history of melanoma or a personal history of non-melanoma skin cancer: yes vs. no
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Education: school-only vs. higher education
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Socio-Economic Indexes for Areas (SEIFA) using the Index of Relative Socio-Economic Advantage and Disadvantage (IRSAD) based on postcode of residence and categorised into five groups using quintile cut-points
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Children: yes vs. no
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Risk taking propensity: risk-averse vs. risk-seeking (see the Domain-specific Risk-taking (DOSPERT) scale below [37])
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Taking medications such as immuno-suppressants that may increase their sensitivity to sunlight (yes, no, don’t know)
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Genetic determinism, measured as How much do you think genetic make-up, that is characteristics that are passed down from one generation to the next, determine whether or not a person will develop melanoma? [38] on a 5-point Likert scale and categorised as 4 or 5 (completely/moderately) vs. 1, 2, or 3 (not at all, slightly, somewhat)
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Genomic risk category (available for the intervention group only): higher than average vs. average vs. lower than average risk
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Discordant genotype/phenotype groups (available for the intervention group only):
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◦ low-risk phenotype but high-risk genotype
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◦ high-risk phenotype but low-risk genotype
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◦ concordant combinations
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Risk-taking – participants were asked to indicate ‘The likelihood that you would engage in the described activity’, from extremely unlikely to extremely likely on a 7-point scale
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Risk perception – participants were asked to indicate ‘How risky you perceive the described situations’ from not at all risky to extremely risky on a 7-point scale
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Risk attitude – participants were asked to indicate ‘The benefits that you would obtain from each situation’, from no benefits at all to great benefits
Domain subscale | Item text |
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Health/safety | Drinking heavily at a social function |
Engaging in unprotected sex | |
Driving a car without wearing a seat belt | |
Riding a motorcycle without wearing a helmet | |
Sunbathing without sunscreen | |
Walking home alone at night in an unsafe area of town | |
Social | Admitting that your tastes are different from those of a friend |
Disagreeing with an authority figure on a major issue | |
Choosing a career that you truly enjoy over a more prestigious one | |
Speaking your mind about an unpopular issue in a meeting at work | |
Moving to a city far away from your extended family | |
Starting a new career in your mid-thirties |