Introduction: PIntroduction: 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 (e.g. walking, music and art therapy, mindfulness training, cooking courses). Methods: A mixed methods study was held among 20 CBSC’s, including 24 visitors about the meaning of their HQoL. In a digital survey at two timepoints (T-1, a few months after the first visit) and again after 3 months-5 months (T-2), the HQoL was studied using three questions of the standardized EORTC measure, beside validated questions on the medical condition, fatigue, sleeping, pain, short-breathing, and perceived prognosis. All measures are very reliable showed by Cronbach alpha coefficients between 0.72 and 0.96. Results: The studies confirmed that visiting CBSCs enable their well-being and the communication about HQoL. In total 203 visitors responded at both time points, revealing that between T1-T2, the HQoL decreased (p<0.05) from 5.3 to 5.1 (seven-point scale). In multivariate analysis the influence of eight confounding factors was studied to explain this result: Social and medical characteristics, medical condition, morbidities, being an (ex) patient or relative with/without cancer, changes in health, stressful life events, number of visits, and perceived meaning of the visits. Only the severity of the medical condition plaid a role in the decrease of HQoL. For visitors with a better medical condition at T-1 the HQoL decreased, while for visitors with a rather worse medical condition at T1, the HQoL did not change. Conclusion: The results confirm the hypothesis that a psychosocial intervention (visiting CBSCs) decreases the HQoL over 3 months-5 months as part of their adaptation process. However, for visitors with a poorer medical condition, the HQoL remained stable over time. This implies that psychosocial interventions (e.g. visiting a CBSC) are functioning as a buffer against decreasing HQoL for those in a poor medical condition only.