PROMs following breast-conserving therapy for breast cancer: results from a prospective longitudinal monocentric study

Background Treatment of breast cancer includes many options and shared decision making is becoming standard practice. Within the context of treatment individualization, the omission of radiotherapy (RT) can be considered. It is thereby of great importance to correctly foresee the side effects attributed to RT. Data from longitudinal studies with contemporary techniques however are sparse. The purpose of the present study was to evaluate patient-reported outcome measures (PROMs) and long-term aesthetic outcome (AO) related to RT in the breast-conserving therapy (BCT) setting for breast cancer over time. Methods Patients treated with BCT between April 2015 and April 2016 were prospectively included in the cohort. Evaluations were made at six time points: at baseline (before RT), during and at the end of RT, between 3 and 6 months, 1 year and 2 years after RT. AO was scored by the patient and by the BCCT.core software. Further PROMs were measured with the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire QLQ-C30/-BR23 and the Body Image after Breast Cancer Questionnaire BIBCQ. Patients were evaluated over 2 years. First, we assessed the evolution in time. Second, we tested the differences in mean scale scores of the PROMs between patients with a favourable and an unfavourable AO. Results One hundred seventy-five patients were included in the analysis. At baseline, unsatisfactory levels were already present for several scales. Most unsatisfactory PROMs improved up to 1 year after RT. Complaints of fatigue increased at the start but decreased up to a lower level than that at baseline up to 1 year after RT (mean difference (MD) 7.6, - 12.3, respectively). Cognitive functioning showed a small decrease at the start with no further significant decrease (MD - 4.73, - 0.21, respectively). Breast symptoms significantly increased during RT but decreased afterwards up to 2 years after RT to lower values than those at baseline and were then considered satisfactory (MD 15.6, - 19.7, - 4.1, respectively). AO scored as PROM associated with BCCT.core and with the body image measures. Conclusions The study suggests that quality of life and body image are temporarily impaired due to RT. Around one third of patients score their long-term AO as unfavourable. These results should be discussed with the patient and could help in the decision making of the treatment plan and in the clarification of the patient's expectations.