Ian Zajac, Ingrid Flight, Carlene Wilson, Tess Gregory, Deborah Turnbull, Steve Cole, Graeme Young

Testing the efficacy of internet-based personalised decision support for colorectal cancer screening

Impact of Colorectal Cancer

Colorectal Cancer is the second most commonly diagnosed cancer and is the second leading cause of cancer-related death in Australia. In 2005, 7,181 males and 5,895 females were diagnosed with CRC.

Personalised Decision Support Trial

So –Why use the web??

• Rapidly increasing usage of Internet amongst the ‘Silver Surfers’

• Users can interact with information in ways that have no precedents in paper documents

• Print is static in nature; while they may contain both text, graphics and images, they may not contain video, animation or sound, which may reinforce the educational message

• Ability to avoid procrastination

So –Why tailor??

• Catch attention• Be read and remembered• Be saved for later reference• Be discussed with others• Be perceived as interesting• By perceived as personally relevant• By perceived as having been written especially for

the reader

Personalised Decision Support Trial

Preventive Health Model (PHM) Constructs*

Salience and Coherence (4 items)“Colorectal cancer screening makes sense to me”Cancer Worries (2 items)“I am afraid of having an abnormal colorectal cancer screening result”Response Efficacy (2 items)“When colorectal cancer is found early, it can be cured”Social Influence (4 items)“My doctor/family thinks I should have colorectal cancer screening”Perceived susceptibility (4 items)“Compared with other persons my age, I am at lower risk for colorectal

cancer”

*Tiro et al (2005), Cancer Epidemiol Biomarkers Prev 14:2855-2861

Personalised Decision Support Trial

Creating a library of tailored messages

FACTOR RESPONSE EFFICACY

Stagesignificanc

e

Not considering; Decided to do

Statement

When colorectal polyps are found, colorectal cancer can be prevented.

Stronglyagree

[Name], you’ve told us that colon cancer screening is effective. You’re absolutely right. That is why the Australian Cancer Council recommends yearly screening for people over 50 who are of average risk. It’s an important step to take to protect your health for the future, and could save your life.

Agree [Name], you’ve told us that you believe colon cancer screening is effective. You’re right. That is why the Australian Cancer Council recommends yearly screening for people over 50 who are of average risk. It’s an important step to take to protect your health for the future, and could save your life.

Not sure [Name], you’re not sure that colon cancer screening is effective. It’s very effective—that’s why the Australian Cancer Council recommends yearly screening for people over 50 who are of average risk. As you are [age], It’s an important step to take to protect your health for the future, and could save your life.

Disagree [Name], you don’t think that colon cancer screening is effective. In fact it’s very effective—that’s why the Australian Cancer Council recommends yearly screening for people over 50 who are of average risk. As you are [age], screening could save your life by finding early, curable cancer.

StronglyDisagree

[Name], you really don’t believe that colon cancer screening is effective. In fact it’s very effective—that’s why the Australian Cancer Council recommends yearly screening for people over 50 who are of average risk. As you are [age], screening could save your life by finding early, curable cancer.

Reinforcing

Motivating

Web based, tailored decision aid for CRC screening

Primary Hypotheses:

1) Access to Tailored PDS improves participation in CRC screening relative to Non-tailored and Control conditions

2) Access to PDS moves people to a higher decision-stage for screening when compared to non-tailored PDS and control groups.

Personalised Decision Support Trial

• Eligibility Criteria:

• 1 Access to the Internet at some location (i.e., home, library

etc)

• 2 Absence of FOBT screening in preceding 12 months

• 3 Absence of Colonoscopy in preceding 5 years

• 4 No clinical diagnosis of Bowel Cancer

Personalised Decision Support Trial

RECRUITMENT

• N=25,000 invitational surveys sent out (N=25,500 in Total)

• Current Stats• N=10,464 returned surveys (41%)• N=8,762 completed the ES (84%)

• N=3421 Eligible... About 40%

• Males: 49%• Females: 51%

• Aged <60: 56.5%• Aged 60 – 70: 36%• Aged 70+: 11.5%

Personalised Decision Support Trial

RANDOMISATION

• Tailored PDS: N=1,137

• Non-Tailored: N=1,136

• Control: N=1135

FOBT INVITATIONS

• Tailored PDS: N=720

• Non-Tailored: N=712

• Control: N=815

Personalised Decision Support Trial

*Stratification levels; State, Sex, Age

75%

82%

81%

0% 20% 40% 60% 80% 100%

Control

Non-Tailored

Tailored PDS

Preliminary Results

Current Participation Rates

Tailored x Control, p=.02;

Non-Tailored x Control, p=.002

Personalised Decision Support Trial

0% 10% 20% 30% 40% 50%

50-54

55-59

60-64

65-69

70-74

Control Non-tailored Tailored

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Control

Non-tailored

Tailored

Female Male

X2(8) = 3.63, p=.88

X2(2) = 0.85, p=.65

• Why does PDS result in improved screening uptake?

• The answer is unknown at the moment:• Follow up behavioural measurements still underway• In-depth qualitative interviews yet to be undertaken• Complex website user data yet to be analysed

Possibilities?

PDS provides instant access to relevant, well organised information prior to receipt of the FOBT kit. Does this help participants move through decision stages easier/faster than otherwise?

Personalised Decision Support Trial

ian.zajac@csiro.au

Questions?