The aim of this study was to investigate the beliefs that patients with advanced cancer held about the curability of their cancer, their use of alternatives to conventional medical treatment, and their need to have control over decisions about treatment. Of 149 patients who fulfilled the criteria for participation and completed a self-administered questionnaire, 45 patients (31%) believed their cancer was incurable, 61 (42%) were uncertain and 39 (27%) believed their cancer was curable. The index of need for control over treatment decisions was low in 53 patients (35.6%) and high in only 17 patients (11.4%). Committed users of alternatives to conventional medical treatments were more likely to believe that their cancer was curable (P<0.001) and to have a higher need for control over decisions about treatment (P<0.004). The mean need for control scores were highest in patients who believed that their cancer was curable, or who were uncertain about the curability of their cancer, but who acknowledged that their oncologist had reported that the cancer was incurable. The diverse beliefs, attitudes and actions of these patients were consistent with a range of psychological adaptations to a life-threatening illness, some realistic and others illusory. Illusory responses influence what communication can achieve in daily oncology practice.