Electronic patient-reported outcome (ePRO) monitoring for patients undergoing cancer chemotherapy may provide qualified and early detection of adverse events or disease-related symptoms, leading to improved patient care. The aim of this study is to examine whether addition of ePRO monitoring to routine medical care contributes to improved overall survival and quality of life of cancer patients undergoing chemotherapy. Patients with unresectable advanced cancers or metastatic/recurrent solid tumors receiving systemic chemotherapy will be randomized to an ePRO monitoring group and a usual care group. The ePRO group will conduct weekly symptom monitoring using an electronic device after study enrollment until the end of the study. Monitoring results will be returned to medical personnel and used as information for patient care. The primary endpoints are overall survival and health related quality of life. The initial target sample size for the study was 1500 patients. However, due to delays in enrollment, the target was readjusted to 500 patients. Enrollment has been completed, and the study is now in the follow-up phase.