Lymph node assessment in endometrial intraepithelial neoplasia: A comparison between Mayo criteria and sentinel lymph node biopsy (599)

Abstract

<b>Objectives:</b> To determine whether the Mayo Criteria or sentinel lymph node biopsy is a better method of lymph node assessment by comparing intraoperative complications, postoperative complications, operative times, and cancer recurrence rates in those with a pre-hysterectomy diagnosis of EIN. <b>Methods:</b> A single institutional retrospective chart review of patients was identified between January 2014 and July 2021 who had a diagnosis of EIN on endometrial biopsy (EMB) or dilation and curettage (D&C) and subsequently underwent management with hysterectomy. Patients were divided into three groups based on the type of lymph node sampling received: complete lymphadenectomy (complete LND), sentinel lymph node biopsy (SLNB), no lymphadenectomy (no LND). The key characteristics compared included EMB/D&C pathology, frozen section pathology, hysterectomy pathology, surgical route, operative time, estimated blood loss (EBL), postoperative complications, and cancer recurrence rates. Statistical significance was determined through Fischer's exact test and Chi-square test calculations. <b>Results:</b> The cohort consisted of 76 patients with a mean age of 56 years and body mass index (BMI) of 43. The majority of the cohort was White (38.2%), Gravida 1 or more (51.6%), and post-menopausal (55.3%). Among the patients, 77.6% had EIN solely on EMB/D&C, and 47.3% were noted to have endometrial cancer on hysterectomy pathology. Of those with endometrial cancer, 34.2% were Stage IA, and 26.3% were FIGO Grade 2. About 51.3% received no LND, 36.8% SNLB, and 11.8% complete LND; 11.1% of patients who had a complete LND developed lymphedema, whereas no SNLB patients had lymphedema (p-value 0.023). Mean EBL of 322 mL for complete LND was greater than the mean EBL of 163 mL for SNLB (p-value 0.035). Among the patients in the no LND group, 5.1% had cancer recurrence compared to zero patients with recurrence in the complete LND and SNLB groups. <b>Conclusions:</b> SNLB should be considered for all patients with EIN on pre-hysterectomy pathology. SNLB balances the risk of postoperative complications with the benefit of allowing for adequate surgical staging.