The aim was to describe the patient attitudes, behaviours, and other factors, considered by doctors when estimating cancer patients' worry about how the disease may develop and the desire for information about the disease and its treatment. Data was gathered through semi-structured interviews with 19 doctors regarding 29 patients within endocrine oncology and haematology care, and the data were analysed by content analysis. The doctors considered the patients' verbal expressions, verbal behaviours, questions, body language, and facial expressions together with their own professional knowledge and experience, when estimating the patients' worry and desire for information. The doctors also considered contextual factors, patients' demographical factors, and medical situation when estimating the patients' worry, and also when estimating the patients' desire for information. The findings illustrate that estimating patients' worry and desire for information is a multifaceted and complex task, and that doctors consider not only the patients' verbal and nonverbal cues, but also factors, such as their own professional knowledge and experience, contextual factors, and patients' demographical variables. The findings should be communicated to doctors who meet cancer patients in medical consultations in order to illuminate the complexity of the medical consultation. The awareness of potentially important patient cues and other factors may aid doctors in their efforts to gain insight about their patients' emotions and informational needs.