Considering population ageing and its association with the estimated growth cases of cancer in Brazil for years 2016 and 2017, being the elderly the most susceptible to that disease, to rethink the perceptions about old age and autonomy by that population is important. This work analyzes the perception that elderly people with cancer have on their participation in decisions of treatments, as seen by patients, relatives, and health care team, and more specifically analyzes intervenient aspects in the participation of elderly people with cancer in decisions about their own treatments. Data were collected through semi-structured interviews with five older patients under cancer treatment, three family members and four health professionals during the hospital stay. Content analysis and interpretation was developed, allowing the elaboration of the categories: autonomy (shared autonomy and the delegation of autonomy); loss of autonomy, approaching dependence; health and disease in old age, approaching the perceptions between disease and aging and the terminologies used to designate the elderly and the old age; autonomy and finitude, approaching the Advance Healthcare Directives and the relationship between the elderly and the health team. This study reveals nuances between the effectiveness of the elderly autonomy and the ideal perception presented by the participants of the research; autonomy can be configured in a self-centered, shared way or delegated, according to context and needs.