Temporal validation of a risk prediction model for breast cancer‐related lymphoedema in European population: A retrospective study

To perform temporal validation of a risk prediction model for breast cancer-related lymphoedema in the European population.Temporal validation of a previously developed prediction model using a new retrospective cohort of women who had undergone axillary lymph node dissection between June 2018 and June 2020.We reviewed clinical records to identify women who did and did not develop lymphoedema within 2 years of surgery and to gather data regarding the variables included in the prediction model. The model was calibrated by calculating Spearman's correlation between observed and expected cases. Its accuracy in discriminating between patients who did versus did not develop lymphoedema was assessed by calculating the area under the receiver operating characteristic curve (AUC).The validation cohort comprised 154 women, 41 of whom developed lymphoedema within 2 years of surgery. The value of Spearman's coefficient indicated a strong correlation between observed and expected cases. Sensitivity of the model was higher than in the derivation cohort, as was the value of the AUC.The model shows a good capacity to discriminate women at risk of lymphoedema and may therefore help in developing improved care pathways for individual patients.Identifying risk factors for lymphoedema secondary to breast cancer treatment is vital given its impact on women's physical and emotional well-being.What problem did the study address? Risk of BCRL. What were the main findings? The prediction model has a good capacity to discriminate women at risk of lymphoedema. Where and on whom will the research have an impact? In clinical practice with women at risk of BCRL.STROBE checklist. WHAT DOES THIS PAPER CONTRIBUTE TO THE WIDER GLOBAL CLINICAL COMMUNITY?: It presents a validated risk prediction model for BCRL.There was no patient or public contribution in the conduct of this study.