This study was conducted to elucidate the prognostic value of patient-assessed quality-of-life (QL) scores in cancer patients. QL was assessed in 47 consecutive patients with advanced or end-stage breast cancer using the Quality of Life Questionnaire for Cancer Patients Treated with Anticancer Drugs (QOL-ACD). The data collected from 19 of the 47 patients, who completed QL questionnaires more than twice before dying of cancer, were analyzed. The relationships between the QL scores and subsequent survival were examined at two assessment points, being the first and last assessment points of each of the 19 patients; corresponding respectively to median survival times of 14 and 4 months. The prognostic significance of the changes in QL scores that occurred over 3 months before the last assessment point was also examined. At the last assessment point, the scores of the physical aspects of QL were significantly related to survival. The change in scores of both overall QL and the physical aspects of QL were also significant predictors of survival. On the other hand, neither the scores nor the change in scores of the psychological and social aspects of QL was significant. This study indicates that both QL scores and changes in QL scores are promising prognostic predictors.