Sentinel lymph node biopsy in extramammary Paget disease: A 13-year institutional experience.

Whether sentinel lymph node biopsy status is a prognostic factor or effective in determining treatment strategies in extramammary Paget disease remains unclear. This study aimed to investigate the significance of sentinel lymph node biopsy in extramammary Paget disease. We retrospectively reviewed the clinical information of previously untreated patients with invasive extramammary Paget disease who underwent wide local excision of the primary tumor and sentinel lymph node biopsy at our hospital between April 2008 and March 2021. Clinical data including the baseline neutrophil-to-lymphocyte ratio and recurrence-free survival were analyzed. Sentinel lymph node metastases were classified as macrometastases and micrometastases, with a cut-off value for sentinel lymph node tumor burden of 2 mm. Univariate and multivariate analyses of factors affecting sentinel lymph node biopsy positivity and recurrence-free survival rates were performed. Overall, 85 patients were included in the analysis. Patients in the sentinel lymph node biopsy-positive group (n = 26) had a significantly higher invasion level and neutrophil-to-lymphocyte ratio. According to multivariate analyses, invasion level and a high neutrophil-to-lymphocyte ratio were independent predictive factors for sentinel lymph node biopsy positivity, and the sentinel lymph node biopsy status was an independent prognostic factor for recurrence-free survival. In conclusion, sentinel lymph node biopsy provides an accurate risk classification and clinical indication for postoperative follow-up in patients with invasive extramammary Paget disease.