Psychosocial treatments may prevent the decrease of the perceived HQoL of cancer patients with a good medical condition. However, contrarily, psychosocial support may not prevent the decrease their HQoL, but only stabilized it, in case of a bad medical condition. The explanatory factor of the effect of psychosocial support may be the severity of the medical condition of patients. This hypothesis was tested in an intervention among Dutch cancer patients visiting a Community Based Support Centre (CBSC), offering contacts with fellow patients, psychological treatment, and participation in supportive activities.