A randomised controlled trial of postoperative radiotherapy following breast-conserving surgery in a minimum-risk older population. The PRIME trial.

OBJECTIVES: To assess whether omission of postoperative radiotherapy in women with 'low-risk' axillary node negative breast cancer (T0-2) treated by breast-conserving surgery and endocrine therapy improves quality of life and is more cost-effective. DESIGN: A randomised controlled clinical trial, using a method of minimisation balanced by centre, grade of cancer, age, lymphatic/vascular invasion and preoperative endocrine therapy, was performed. A non-randomised cohort was also recruited, in order to complete a comprehensive cohort study. SETTING: The setting was breast cancer clinics in cancer centres in the UK. PARTICIPANTS: Patients aged 65 years or more were eligible provided that their cancers were considered to be at low risk of local recurrence, were suitable for breast-conservation surgery, were receiving endocrine therapy and were able and willing to give informed consent. INTERVENTIONS: The standard treatment of postoperative breast irradiation or the omission of radiotherapy. MAIN OUTCOME MEASURES: Quality of life was the primary outcome measure, together with anxiety and depression and cost-effectiveness. Secondary outcome measures were recurrence rates, functional status, treatment-related morbidity and cosmesis. The principal method of data collection was by questionnaire, completed at home with a research nurse at four times over 15 months. RESULTS: The hypothesised improvement in overall quality of life with the omission of radiotherapy was not seen in the EuroQol assessment or in the functionality and symptoms summary domains of the European Organisation for Research in the Treatment of Cancer (EORTC) scales. Some differences were apparent within subscales of the EORTC questionnaires, and insights into the impact of treatment were also provided by the qualitative data obtained by open-ended questions. Differences were most apparent shortly after the time of completion of radiotherapy. Radiotherapy was then associated with increased breast symptoms and with greater fatigue but with less insomnia and endocrine side-effects. Patients had significant concerns about the delivery of radiotherapy services, such as transport, accommodation and travel costs associated with receiving radiotherapy. By the end of follow-up, patients receiving radiotherapy were expressing less anxiety about recurrence than those who had not received radiotherapy. Functionality was not greatly affected by treatment. Within the randomised controlled trial, the Barthel Index demonstrated a small but significant fall in functionality with radiotherapy compared with the no radiotherapy arm of the trial. Results from the non-randomised patients did not confirm this effect, however. Cosmetic results were better in those not receiving radiotherapy but this did not appear to be an important issue to the patients. The use of home-based assessments by a research nurse proved to be an effective way of obtaining high-quality data. Costs to the NHS associated with postoperative radiotherapy were calculated to be of the order of 2000 pounds per patient. In the follow-up in this study, there were no recurrences, and the quality of life utilities from EuroQol were almost identical. CONCLUSIONS: Although there are no differences in overall quality of life scores between the patients treated with and without radiotherapy, there are several dimensions that exhibit significant advantage to the omission of irradiation. Over the first 15 months, radiotherapy for this population is not a cost-effective treatment. However, the early postoperative outcome does not give a complete answer and the eventual cost-effectiveness will only become clear after long-term follow-up. Extrapolations from these data suggest that radiotherapy may not be a cost-effective treatment unless it results in a recurrence rate that is at least 5% lower in absolute terms than those treated without radiotherapy. Further research is needed into a number of areas including the long-term aspects of quality of life, clinical outcomes, costs and consequences of omitting radiotherapy