Cancer patients suffer from a variety of problems, somatically, socially and psychologically. Somatically, the illness and treatment threaten physical integrity. Cancer is an insidious disease, in which the patient is severely ill before he notices any symptoms. The (mostly) invasive treatment often results in the patient feeling worse after treatment than before. This means that the confidence the patient has in his own body is diminished. Socially, the illness, treatment and its consequences (tiredness, lack of energy, feeling ill) may result in social isolation. This can be increased by the fear and uncertainty of by-standers how to approach the patient, what to say to him, and what to expect from him. Psychologically, the patient has to cope with the emotional consequences of the illness, such as changes in life perspective, mourning his lost health, and anxiety and uncertainty about the future. The literature on the prevalence of psychological distress in cancer patients is equivocal. The percentages of depressed and/or anxious patients reported in the literature vary widely from 0% to 49% (cf. Bulman, 1992; Omne-Ponten, Holmberg, Burns, Adami & Bergstrom, 1992; Devlen, Maguire, Phillips, Crowther & Chambers, 1987). It is worthwhile to solve the lack of clarity on this point. This leads to the first research question of this thesis: what is the prevalence and course of psychological distress in cancer patients?