Announcing a cancer diagnosis, but also a relapse, a progression of the disease, or transition towards palliative care constitute particularly difficult communication issues for the patient as well as for the clinician, during the trajectory of care. The objectives of this article is to present the clinical stakes of these situations, to describe the difficulties in establishing a "good" doctor-patient relationship, to provide indications or even recommendations on the ways to facilitate communication in order to ensure a optimal quality of care, responding to patients needs and ensuring the continuity of the care. Communication relates to the relation and the information delivered between patient and clinician, but also within the medical team. We analyse here the essential components of the process of "diagnosis consultation", organised in many cancer centers around France. In addition, we present the diverse training programs on communication skills that have been developed and tested in the setting of oncology, open to all professionals. Its specificity relates to its multidisciplinary character; the quality of the doctor-patient communication also depends on the quality of the communication and coordination within the team. This dimension is the subject of specific attention carried by supportive care teams.