Patient's Choice in the Reduction of Their Treatment in Women Over 65 Year With Breast Cancer

Current demographic trends lead to an increasing number of breast cancers among 70+ women. In this population, adjuvant whole-breast radiation therapy (WBRT) after breast conserving surgery has proven its advantage on local control, but does not improve survival. Some experts are thus advocating WBRT omission. In this context of limited life expectancy and of frequent comorbidities, therapeutic de-escalation (DE) might be proposed. Two options of de-escalation have been considered: (1) omission of adjuvant breast irradiation and (2) limiting the breast irradiated volume through a single-dose targeted intraoperative radiotherapy (IORT). As each of the three options (standard WBRT, IORT or no irradiation at all) has significant harms and benefits, treatment decision-making should not rely on the physician's opinion only. A recent study has shown that in this context older women desire information and have more agency and input in the decision-making process than prior literature would suggest. The impact of therapeutic de-escalation on objective indicators and on patient reported outcomes must be investigated in current clinical practice, as uncertainties and doubt are likely to affect the decision-making process. When there is no definitive evidence to favour a treatment decision, assessing the patients' values and preferences appear to be of great relevance and value. Thus, the impact of therapeutic de-escalation on objective indicators and on patient reported outcomes (PROs) and experience (PRE) must be investigated, as uncertainty is likely to affect the decision-making process. We therefore propose to study the women's choice and experience of de-escalation of radiotherapy. An encounter decision aid will be used to standardize the information provided about the three options and their outcomes. A prospective multicentre study using self-administered questionnaires before and after treatment decision making will then examine: * the patient's choice and the impact of medical and patients' characteristics on this choice, * the reason for the therapeutic choice from the patient's point of view, * the experience of DE (patient-reported outcomes), and its medical effects (including care trajectories). This study will document the rate and reasons of DE choice among French elderly early breast cancer patients. The results should facilitate the physician's reasoning at the time of treatment decision, and will also help patients (and their relatives) become better informed of the potential consequences of their choices. Developing a patient decision aid might also promote higher quality choices and shared decision-making in this context.