Abstract PS1-06-03: Lymph Node Evaluation in Breast Cancer: A Comparative Study of CNB and FNA

Abstract Background: accurate lymph node evaluation is essential for breast cancer staging, treatment planning and diagnosis of recurrent disease. Fine-needle aspiration (FNA) and core needle biopsy (CNB) are the two main percutaneous techniques used, but they differ in diagnostic yield, complication rates and associated healthcare costs. Objectives: to compare the diagnostic performance and economic impact of FNA versus CNB for lymph node evaluation in breast cancer patients within the Brazilian public healthcare system, emphasizing the relevance of cost-effective strategies in low- and middle-income countries (LMICs). Methods: a retrospective cohort study was conducted, including women with suspicious lymph nodes who underwent FNA or CNB between 2015 and 2023. A 1-year budget impact model nested with a decision tree model was used as economic model. Probabilities from the cohort study were used as clinical inputs. Costs were obtained from Sigtap (Brazilian listing of procedures reimbursement). The economic analysis considered only the procedural cots, assuming that each patient could undergo either FNA or CNB as the initial approach. In cases of inconclusive results, the patient could then undergo CNB or surgery. All analyses were reported as American dollar (USD), using an exchange rate of 6 brazilian reais to 1 USD. Results: the 300 women included in the study had similar ages (FNA: 53 vs CNB: 54 years old, average). The overall rate of inconclusive results in the sample was 15%. The rate of inconclusive results in procedures performed with CNB was lower than FNA (2.7% vs. 50.7%, p