Colorectal cancer (CRC) is one of the leading causes of cancer morbidity and mortality in the industrialized world [
1]. Most cases (93%) occur in persons aged 50 years or more [
2] and it often co-exists with other chronic diseases related to health behaviours including obesity, type 2 diabetes mellitus and cardiovascular disease [
3,
4]. Behavioural risk factors including physical inactivity [
5], diet [
6-
8] and obesity [
9-
11] play a pivotal role in the aetiology of CRC, and it has been estimated that at least 70% of CRC may be prevented with moderate behavioural changes [
12]. In particular, reductions in the consumption of alcohol and red and processed meat, weight loss and increased levels of physical activity may translate into significant reductions in the incidence of CRC [
12]. Importantly, these lifestyle changes also decrease risk of other cancers as well as type 2 diabetes mellitus and cardiovascular disease [
13,
14], therefore behavioural improvements result in overall health benefits.
Individuals with a family history of CRC have a significantly elevated risk of developing CRC [
15]. Epidemiological studies indicate that first degree relatives of CRC survivors (parents, siblings, or offspring) have a 1.6 to 8-times higher life time risk of CRC than those without a family history, the strength of the relationship varying according to age at diagnosis in the index case, type of relative, and the number of relatives affected [
15]. Furthermore, a combination of familial predisposition and unhealthy behaviours increases risk of CRC considerably [
16].
Despite the evidence, research has shown that most people are unaware of the association between behavioural risk factors and CRC risk [
17], and individuals identified at high risk of CRC do not generally make voluntary behavioural changes [
18]. One study found that first degree relatives of CRC survivors attributed their risk of CRC to physiology (27%) or family history (25%), whilst only 16% believed behavioural risk factors were of importance [
19]. As such, it is important to educate people about the importance of their health behaviours and to support those at high risk of CRC to make improvements to reduce their risk of the disease. To our knowledge, there are no programs routinely available to support individuals considered at increased risk of CRC. The absence of specific programs for this population group remains a missed opportunity as national policy supports cancer reduction and the evidence suggests that behaviour change programs targeting high risk groups may be more effective than those targeting the population at large [
20,
21].
There is also a paucity of research investigating educational or supportive interventions specifically for those at high risk of CRC with, to our knowledge, just two published studies in the field specifically targeting those with colorectal adenomas [
20,
21].
Bowel health to better health was a trial of a three month minimal contact intervention (one face to face session followed by three personalised mailings; n=74). The intervention included lifestyle advice, goal setting and social support to promote increases in physical activity, fibre, fruit and vegetable intake. However, the study was limited by a low response rate (51%), and intervention effects were observed for fibre intake alone [
20]. Project PREVENT was a trial of a tele-based counselling intervention based on Social Cognitive Theory [
22] to improve multiple risk factors (red meat, fruit, vegetable, multivitamin and alcohol intake, smoking, and physical activity; n=1247). Intervention effects were observed for multiple risk factors (including multivitamin and red meat intake), and intervention participants tended to have a lower rate of regression in their levels of physical activity than usual care participants. However, there were no direct intervention effects on smoking, alcohol, fruit or vegetable intake, and the study was limited by the inclusion of participants who were highly educated [
21].
Behavioural risk factors for CRC are interrelated in terms of the psychological, social and environmental factors that reinforce them [
23] (for example, those who eat high-fat diets are more likely to be sedentary and to be cigarette smokers) [
22,
24,
25]. Also, previous investigations [
24,
26] have shown that change in one behavioural risk factor may serve as a stimulus or gateway for change in other health behaviours. However, few CRC studies have intervened on multiple behaviours simultaneously. It represents a challenge from an intervention perspective, but provides an important opportunity to maximise the potency of cancer prevention interventions as the complex and multifactorial process of carcinogenesis suggests that several behavioural changes may be needed to significantly reduce risk. Thus multiple risk factor interventions warrant further study [
21].
Theory-based behavioural interventions have been shown to be most effective and Social Cognitive Theory is widely used [
22,
27]. In contrast, the CanPrevent intervention used specific strategies from Acceptance Commitment Therapy (ACT), which is an empirically based third generation cognitive behavioural approach that uses acceptance and mindfulness strategies, and commitment and behaviour change strategies to produce psychological flexibility: the ability to defuse from difficult thoughts and accept difficult feelings while persisting in values-based action [
28-
31]. This provided an alternative to existing intervention approaches by overcoming internal barriers to making lifestyle improvements by emphasizing the role of emotions and thoughts in the maintenance of good self-management of lifestyle factors [
32]. To date, ACT interventions have been successfully used to enhance quality of life and promote positive lifestyle behaviours for a range of health conditions (chronic pain [
33], diabetes [
34], epilepsy [
35], smoking [
36], and obesity or weight management [
37-
39]) but this approach has not previously been used for those at high risk of CRC.
Previous researchers have investigated a range of delivery modes for behavioural interventions (face to face, telephone, internet and paper-based delivery) and telephone-delivered interventions have been shown to be highly acceptable [
40], improve behavioural outcomes in the short term [
41,
42] for cancer survivors, and there is a solid evidence base supporting the efficacy of telephone based interventions for physical activity and dietary behaviour change [
43,
44]. Importantly, in Australia, approximately 96% of the population live in a household with at least one telephone connection, hence this approach appeared viable for the current study [
45].
This is the first pilot study of the acceptability and short-term effectiveness of a novel theory-based telephone-delivered multiple risk factor intervention to improve behavioural risk factors, health-related quality of life (HRQoL) and perceived risk of CRC for first degree relatives of CRC survivors.