The Japan National Committee for the Union for International Cancer Control (UICC) and UICC-Asia Regional Office (ARO) organized an international session as part of the official program of the 72nd Annual Meeting of the Japanese Cancer Association to discuss the topic "What is cost-effectiveness in cancer treatment?" Healthcare economics are an international concern and a key issue for the UICC. The presenters and participants discussed the question of how limited medical resources can be best used to support life, which is a question that applies to both developing and industrialized countries, given that cancer treatment is putting medical systems under increasing strain. The emergence of advanced yet hugely expensive drugs has prompted discussion on methodologies for Health Technology Assessment (HTA) that seek to quantify cost and effect. The session benefited from the participation of various stakeholders, including representatives of industry, government and academia and three speakers from the Republic of Korea, an Asian country where discussion on HTA methodologies is already advanced. In addition, the session was joined by a representative of National Institute for Health and Care Excellence (NICE) of the United Kingdom, which has pioneered the concept of cost-effectiveness in a medical context. The aim of the session was to advance and deepen understanding of the issue of cost-effectiveness as viewed from medical care systems in different regions.