Risk factors for nonvisualization of the sentinel lymph node on lymphoscintigraphy in breast cancer patients

Background: Accurate sentinel lymph node (SLN) staging is essential for both prognosis and treatment in patients with breast cancer. However, the preoperative lymphoscintigraphy may fail to visualize the SLN in some patients. The purpose of this retrospective study was to identify risk factors associated with SLN nonvisualization on lymphoscintigraphy. For this single-center retrospective study, all data of lymphoscintigraphy of SLN procedures from March 2011 to April 2021 were collected and reviewed from the Amsterdam UMC database. Results: A total of 1886 SLN procedures were included in this study. The SLN nonvisualization rate was 25.1% on lymphoscintigraphy at 4 h post-injection. The SLN nonvisualization rate decreased to 9.4% after reinjection. Multivariable analysis showed that age ≥ 70 years (P < 0.001; OR: 2.27; 95% CI: 1.46–3.53), BMI ≥ 30 kg/m ² (P = 0.031; OR: 1.48; 95% CI: 1.04–2.12) and nonpalpable tumors (P = 0.004; OR: 1.54; 95% CI: 1.15–2.07) were independent predictors of SLN nonvisualization. Tumor location, brand of radiopharmaceutical, injected dose and volume, experience of preparer and administrator were not associated with SLN nonvisualization. None of the patient, tumor or tracer characteristics were associated with SLN nonvisualization after radiotracer reinjection. Conclusions: This study shows that risk factors for SLN nonvisualization in breast cancer patients during preoperative lymphoscintigraphy are age ≥ 70 years, BMI ≥ 30 kg/m ² and nonpalpable tumors. Our results support the notion that SLN lymphoscintigraphy is a very robust technique that does not depend on the experience of the preparer or administrator of the radiotracer.