The paper reviews published studies focused on disparities in receipt of cancer treatments and supportive care services in countries where cancer care is free at the point of access. We map these studies in terms of the equity stratifiers they examined, the countries in which they took place, and the care settings and cancer populations they investigated. Based on this map, we reflect on patterns of scholarly attention to equity and disparity in cancer care. We then consider conceptual challenges and opportunities in the field, including how treatment disparities are defined, how equity stratifiers are defined and conceptualized and how disparities are explained, with special attention to the challenge of psychosocial explanations.