With cancer incidence increasing over time worldwide, attention to the burden of psychiatric and psychosocial consequences of the disease is now mandatory for both cancer and mental health care professionals. Psychiatric disorders have been shown to affect at least 30-35% of cancer patients during all phases of the disease trajectory, and differ in nature according to stage and type of cancer. Other clinically relevant distressing psychosocial and existential conditions (e.g. demoralisation, health anxiety, loss of meaning and existential distress) not included as 'disorders' in the usual diagnostic and nosological systems (i.e. meta-diagnostic conditions) have also been shown to be present in another 15-20% of cancer patients. In this editorial, we will present a summary of the extensive literature regarding the epidemiology of the several psychosocial disorders affecting cancer patients as a cause of distress and burden to be taken into consideration and addressed in cancer care through evidence-based intervention.