Psychometric properties and responsiveness of the EORTC quality of Life Questionnaire (QLQ-C30) in patients with breast, ovarian and lung cancer.

The QLQ-C30, a health-related quality of life questionnaire developed for use in patients with cancer, has been previously validated in patients with lung cancer and head and neck cancer. In this study, further validation was carried out for 535 patients, including patients with breast cancer (n = 143) and ovarian cancer (n = 111) for whom there is no previously published validation, as well as patients with lung cancer (n = 160) and a heterogeneous group of other cancers (n = 121). All patients were entered in one of two trials of anti-emetics to prevent chemotherapy-induced emesis. The QLQ-C30 was completed before chemotherapy and on day 8 after chemotherapy. The factor structure in patients with breast and ovarian cancer was similar to that previously described. Interdomain correlations, in the entire group, were strongest for the physical and role function domains and the fatigue, pain and global quality of life domains before and after chemotherapy. In addition, after chemotherapy, social function was also strongly correlated with fatigue and global quality of life. These correlations were not always of equal strength in the breast, ovarian and lung groups, suggesting that there may be differences between these groups. The responsiveness of the QLQ-C30 in the presence of widely metastatic, as compared with locoregional, disease showed changes in the expected directions (i.e., diminished function in physical and social role functions and in global quality of life, with greater fatigue and pain in patients with metastatic disease). Eight days after chemotherapy, decreases were seen in physical, role and social functioning and in global quality of life, and there was greater fatigue, nausea and vomiting compared with before chemotherapy. Patients with breast cancer had better physical, role and social functioning and less fatigue and pain than patients with ovarian cancer. This result is expected, since many of the patients with breast cancer had early stage disease, whereas those with ovarian cancer had advanced stage disease. Mean scores for patients with lung cancer were between the other two groups, in keeping with the mixture of early and advanced stage disease in these patients. There was a strong correlation between ECOG performance status scores and several domains of the QLQ-C30; these were all in the expected directions. The results of this study confirm those in earlier studies on patients with lung cancer, and provide new information on patients with breast and ovarian cancer. In addition, the QLQ-C30 is responsive to the effects of chemotherapy and of metastatic disease.