Background & Problems: The return-to-treatment rate is an important indicator of treatment outcome and care effectiveness in cancer patients. The return-to-treatment rates for patients at National Taiwan University Hospital (NTUH) in 2011 and 2012 were 38.5% and 33.3%, respectively. In order to improve the quality of care that is provided to patients, we reviewed NTUH's current clinical case management protocols for handling patients who refused treatment and then identified and resolved the potential problems in these protocols. Purpose: To raise the return-to-treatment rate above 45% by 2013. Resolution: We developed four new interventions to improve the return-to-treatment rate. Firstly, we assembled a quality care team that monitored the rates of patient return to treatment on a monthly basis and reminded case managers to follow up with patients regularly. Secondly, we introduced new protocols for case managers that facilitated the ongoing analysis of the reasons that patients elect not to return to treatment. Thirdly, we delivered regular education programs for case managers addressing good quality and quantity care for cancer patients. Finally, we developed an interdisciplinary liaison care program for patients. Result: After implementing these four interventions, the return-to-treatment rate improved to 48% in 2013. Conclusion: This improvement project demonstrated that integrating an interdisciplinary team, assembling a quality care team, implementing new protocols to help cancer patients who refuse to commence / continue treatment, providing regular education to clinical case managers, and enacting an interdisciplinary care program were all helpful to improving the effectiveness of cancer care services and the return-to-treatment rate of cancer patients.