BACKGROUND: Several prognostic tools have been developed to aid clinicians in survival prediction. However, changes in symptoms are rarely included in established prognostic systems. We aimed to investigate the influence of changes in symptoms and quality of life (QOL) on survival time in outpatients with advanced cancer. METHODS: Study subjects included a subgroup of those with longitudinal symptom and QOL data within a larger, single-site parent study. We assessed patients' symptoms and QOL at enrollment and follow-up at an approximately 3-month interval. Patients' symptoms were evaluated by the Korean version of the Edmonton Symptom Assessment System (K-ESAS). QOL was checked by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Participants were categorized into three groups by changes in symptoms or QOL. These groups were: improved (having at least a one level of improvement in the response scale), stable (no change), or worsened (at least a one level of worsening in the scale). We compared survival time in the improved plus stable vs. worsened groups, using a log-rank test. RESULTS: We analyzed 60 patients, with a median survival time of 346 days. In the Worsened group, depression (P<0.01) and sleep disturbance (P<0.01) by K-ESAS, and dyspnea (P<0.03) per the EORTC QLQ-C30, were statistically significantly related to shorter survival time compared to 'improved and stable' group. There was no relationship between changes in other symptoms, overall QOL, and survival. CONCLUSIONS: Longitudinal assessment of depression, sleep disturbance and dyspnea may be useful in prognostication of patients with advanced cancer. Further studies are needed to confirm our findings with more consecutive assessments in diverse populations.