ABSTRACT: BACKGROUND:The application of game-based learning in clinical practice has shown potential advantages in previous studies. However, there have been little efforts to use smartphone-based mobile games in the management of adult patients with cancer. OBJECTIVE:The objective of our study was to evaluate if patient education using a mobile game may increase drug compliance, decrease physical side effects of chemotherapy, and improve psychological status in breast cancer patients. METHODS:A total of 76 patients with metastatic breast cancer who were planned to receive cytotoxic chemotherapy were enrolled in this trial. Study participants were randomly assigned to a mobile game play group (game group, n=36) or a conventional education group (control group, n=40) in a ratio of 1:1. The patients were unblinded and followed prospectively for 3 weeks. Outcome measures included time spent for education, compliance to medication, physical side effects, and psychological side effects including quality of life (QoL). RESULTS:Overall, 72 out of 76 patients completed the study after 3 weeks (95%). The subjects in the game group showed high levels of satisfaction with the app. The time spent playing the mobile game in the game group was longer than that spent for self-education in the control group (mean 22.2, SD 6.1 vs mean 5.5, SD 4.0 minutes a day; P<.001). The mobile game group showed better drug adherence (Korean version of the Medication Adherence Rating Scale; mean 7.6, SD 0.7 vs mean 6.5, SD 0.5; P<.001). The use of the mobile game was associated with lower rates of chemotherapy-related side effects, such as nausea, fatigue, numbness of hand or foot, and hair loss, than the control group. The game group exhibited better QoL during chemotherapy (mean 74.9, SD 3.5 vs mean 72.2, SD 5.3; P=.01). However, there were no significant differences in terms of depression and anxiety scales. CONCLUSIONS:This study suggests the feasibility and potentiality of the use of smartphone mobile games for patients with breast cancer receiving chemotherapy. Education using a mobile game led to better patient education, improved drug compliance, decreased side effects, and better QoL compared with conventional education. Mobile games can be used as easy, fun, and effective measures for patient education and have the potential to improve treatment outcomes. TRIAL REGISTRATION:ClinicalTrials.gov NCT03205969; http://clinicaltrials.gov/ct2/show/NCT03205969 (Archived by WebCite at http://www.webcitation.org/71jfSBOq9).