Background: The emotional functioning (EF) dimension of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C33) and the Hospital Anxiety and Depression Scale (HADS) evaluate anxiety and depression. We wanted to compare cancer patients' responses to EF with those to HADS, as well as the impact of anxiety and depression on the quality of life (QL) dimensions of the EORTC QLQ C33.
Method: A total of 568 cancer patients completed both the EORTC QLQ C33 and HADS at the same occasion. The association between the patients' EF scorings and their HADS scores was analyzed by multiple linear regression. Gender and age were included as covariates.
Results: Statistically significant negative relations were found between EF and HADS-A (anxiety), HADS-D (depression) and HADS-T (total score), respectively, with the highest correlation coefficient for HADS-A. Older patients and males reported less emotional distress assessed by the EF scale than younger ones and females with comparable HADS-T or HADS-D scores. Both HADS-A and HADS-D were significantly related to other QL dimensions, and depression was a stronger predictor for reduced QL than anxiety.
Conclusion: The EF dimension of EORTC QLQ C33 predominantly assesses anxiety, whereas depression is rated to a lesser degree. Combined with significant age and gender relations, this implies a risk of underdiagnosed depression, if the EORTC QLQ C33 is used as the only instrument to screen for psychological distress in cancer patients. As depression has a stronger impact on global QL of cancer patients than anxiety, the use of an additional instrument is recommended for assessment of depression.