Little is known about the behavioral determinants that underlie cancer patients' intention to express concerns during a consultation. This information can be relevant to developing effective interventions for cancer patients. In this study, the integrative model of behavioral prediction (IMBP) is used as a framework to unravel the determinants of patients' intention to express concerns. The objectives of this study are to examine which of the IMBP determinants (attitude, perceived social norm, and=or self-efficacy) are significantly related to intention and what content of these determinants can be targeted to effect a change in patients' intention. An online survey based on the IMBP determinants was distributed. A total of 236 cancer patients and cancer survivors participated. The results of the survey showed that patients' attitudes and perceived social norm were the most important determinants of their intention to express concerns. The largest change in patients' intention might be achieved by targeting the affective attitude, referring to the extent to which patients believe that expressing concerns is (un)pleasant, and the social norm, referring to the extent to which patients feel (un)supported by significant others in expressing concerns.A life-threatening disease such as cancer can evoke many concerns in patients (Farrell, Heaven, Beaver, & Maguire, 2005). A concern is defined as ''a clear and an unambiguous expression of an unpleasant current or recent emotion where the emotion is explicitly verbalized ('I am worried', 'I am upset')'' (Zimmermann et al., 2011, p. 144). Concerns that are experienced by patients include medical concerns (e.g., patients are worried about the possible side effects of their treatment), psychosocial concerns (e.g., patients are anxious that they might not survive cancer), and practical concerns (e.g., patients are concerned about whether they can keep their jobs; Chaturvedi, Shenoy, Prasad, Senthilnathan, & Premlatha, 1996;Hill, Amir, Muers, Connolly, & Round, 2003).Studies have indicated that many cancer patients do not express these concerns sufficiently. For example, patients often express their concerns indirectly with cues (i.e., unclear verbal or nonverbal hints of experienced concerns) rather than directly (Grimsbø, Ruland, & Finset, 2012;Heyn, Ruland, & Finset, 2012). Health care providers often do not notice those cues and indicate that they better detect concerns when these concerns are expressed explicitly (Butow et al., 2008). When concerns are explicitly verbalized by patients, it is easier for health care providers to respond adequately. Receiving adequate information to address concerns has been associated with positive outcomes for patients, such as better psychological well-being (de Haes & Bensing, 2009;Street, Makoul, Arora, & Epstein, 2009). In contrast, when patients do not explicitly express concerns, and these concerns remain undetected, they can worsen and possibly lead to depression (Chochinov, 2001;Ryan et al., 2005). Thus, it is important to suppor...