The extent of information to cancer patients is, in general, culture-dependent. Information mainly refers to three aspects, namely diagnosis (Dx), prognosis (Px) and treatment (Rx), but the relative contribution of each domain to the information given overall is not available. To address this issue, we e-mailed a questionnaire to 9893 members of the American Society of Clinical Oncology (ASCO) asking whether they agree that information about Dx, Px and Rx contribute differently to the information given to the cancer patient overall and, if so, to what extent, both in the adjuvant and advanced settings. 857 questionnaires were evaluable. There was no statistically significant difference between the contribution of these 3 domains in the adjuvant setting (33%, 34% and 33%, respectively). In subgroup analysis, medical oncologists and haematologists attributed a significantly higher contribution of Px information compared with other specialists (P<0.05). In the advanced setting, respondents estimated a higher contribution of Px (41%) to patient information overall compared with Dx and Rx (28% and 31%, respectively; P<0.05). This finding was more pronounced in North America than in Europe (P<0.0001), and in Germanic-language than in Romance-language countries (P=0.005). In conclusion, information on Dx, Px and Rx are believed to contribute differently to the information delivered to cancer patients overall, depending on the stage of disease, the cultural environment and the specialty of the physician.