Iris Kanera

6 133 Long-term effects of the Kanker Nazorg Wijzer BACKGROUND Cancer represents a large global health problem, with approximately 14.1 million new cases of cancer in 2012, worldwide (World Health Organization, 2017; Cancer Research UK, 2016). Due to aging and improvements in treatment, the number of cancer survivors is growing. As a consequence of primary cancer treatment, cancer survivors’ quality of life (QoL) can be reduced by physical and psychosocial health problems, such as pain, fatigue, anxiety, depression, and work-related issues (Aaronson et al., 2014; Deckx et al., 2015). Moreover, survivors are at risk of disease recurrence, and comorbid chronic conditions (Kenzik, Kent, Martin, Bhatia, & Pisu, 2016). In particular, survivors who smoke, are physically inactive, or overweight are at increased risk for mortality, morbidity, and disability (Bruno et al., 2016; Schmid & Leitzmann, 2014; Tsilidis et al., 2016). A healthy dietary pattern has been associated with a lower risk of obesity, hypertension, and unfavorable cholesterol and glucose blood levels, which in turn may be related to a lower risk of cancer recurrence (Bruno et al., 2016). Particularly, the consumption of vegetables has been associated with a lower risk of cancer recurrence among breast cancer survivors (Thomson et al., 2011). Moreover, a growing body of evidence has shown that cancer survivors’ QoL can be improved by adopting and maintaining a healthy lifestyle (Baena Ruiz & Salinas Hernandez, 2013; Bruno et al., 2016; Carmack et al., 2011; Husson et al., 2015; Koutoukidis et al., 2015; Schmid & Leitzmann, 2014; Smits et al., 2015; Thomson et al., 2011). For example, physical activity (PA) has been shown to improve psychological outcomes, fatigue, body composition, walking distance, aerobic fitness, strength, and QoL domains (Fong et al., 2012; Mishra et al., 2014; Van Dijck et al., 2016). In particular, aerobic exercise with moderate-intensity appeared to be a strong positive factor affecting fatigue, walking endurance, and cancer mortality (Dennett, Peiris, Shields, Prendergast, & Taylor, 2016; Inoue-Choi et al., 2013). According to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and the American Cancer Society (Blanchard et al., 2008; Inoue-Choi et al., 2013; World Cancer Research Fund, 2009; Rock et al., 2012), adult cancer survivors should avoid inactivity. It is recommended that cancer survivors engage in at least 150 minutes per week (min p/w) of moderate PA, spread throughout at least 5 days of the week, or perform 75 min p/w of vigorous PA (or an equivalent combination). A healthy diet should include at least five servings of fruit and vegetables daily (Rock et al., 2012). Despite the beneficial effects of recommended PA and healthy diet, the great majority of cancer survivors fail tomeet the lifestyle recommendations (Blanchard et al., 2008; DeNysschen et al., 2015; Kanera et al., 2016a; Mowls et al., 2016). Meeting the individual needs of a growing number of cancer survivors, including the promotion of a healthy lifestyle, is challenging. Therefore, fully automated web-based interventions may be appropriate for providing a large population with easily accessible and low-cost support that can be personalized by applying computer tailoring (Chou et al., 2011; de Vries & Brug, 1999; Kohl et al., 2013; Noar et al., 2007). Moreover, web-based interventions