Choosing observers for evaluation of aesthetic results in breast cancer conservative treatment.

PURPOSE The subjective evaluation of aesthetic results in conservative breast cancer treatment has largely been used without questioning the observer's skills. The aim of this study was to evaluate interobserver agreement of the aesthetic results of breast cancer conservative treatment in three groups of observers with different levels of experience. METHODS AND MATERIALS Photographs were taken of 55 women who had undergone conservative unilateral breast cancer treatment and 5 control women with no breast disease. The images were then distributed to 13 observers who were divided into three groups according to their experience in breast cancer treatment: experienced, medium experienced, and inexperienced. They were first asked to distinguish the patients from the controls and for the patients to identify the operated side. Subsequently, they were asked to classify the aesthetic result as excellent, good, fair, or poor. The accuracy in identifying controls, patients, and side of treatment was calculated individually for all observers. The interobserver agreement for the aesthetic result was calculated using observed agreement and multiple kappa statistic (kappa) in each of the three groups. RESULTS Inexperienced observers performed significantly worse than experienced observers in identifying controls, patients, and the side of treatment. Agreement of the aesthetic result was significantly greater in the group of experienced observers (kappa = 0.59) than in the medium experienced (kappa = 0.35) and inexperienced (kappa = 0.33) observers. CONCLUSION Previous experience in breast cancer conservative treatment should be considered a prerequisite for the evaluation of the aesthetic results.