Clinical impact of second radiotracer injection after failed lymphoscintigraphy in breast cancer sentinel lymph node biopsy: a retrospective cohort study

Abstract

Abstract Background Sentinel lymph node biopsy (SLNB) is the standard method for axillary staging in breast cancer. To ensure the identification of sentinel lymph nodes (SLNs), lymphoscintigraphy (LS) is often used. However, failure of LS remains a clinical challenge. A second tracer injection has been shown to help improve the success of SLNB, but its association with surgical outcomes has been insufficiently studied. In this study, the effect of a second isotope injection on SLNB outcomes was investigated. Methods This retrospective study included 2,466 patients undergoing LS with peritumoral radiotracer injection between 2010 and 2022. Second tracer injection was administered if initial LS was unsuccessful. Factors associated with failed initial LS were analyzed using univariable and multivariable methods. Propensity score matching (3:1) was performed to assess differences between patients with successful and failed initial LS. SLNB outcomes were evaluated. Results Initial LS failed in 397 (16.1%) of patients. In multivariable analysis, older age, higher body mass index, tumor location and tumor multifocality were associated with LS failure. Tumors located in the upper medial quadrant were overrepresented among failed LS cases, whereas central tumors were underrepresented. SLNB was technically equally successful after failed and successful LS (97.5% in both groups). Patients with failed LS had a higher proportion of sentinel node-negative disease (OR 0.42, p < 0.0001). Conclusions Second subareolar radiotracer injection after failed initial LS appears to be an effective salvage strategy for maintaining SLNB technical success. The observed lower nodal positivity rate among failed-LS patients may reflect altered lymphatic drainage patterns or patient selection and requires further validation.