Diagnostic accuracy of frozen section and patterns of nodal spread in high grade endometrial cancer: A secondary outcome of the SENTOR prospective cohort study

• Published in: Gynecologic oncology 2023-06, Vol.173, p.41-48
• Main Authors: Marchocki, Zibi, Cusimano, Maria C., Vicus, Danielle, Pulman, Katherine, Rouzbahman, Marjan, Mirkovic, Jelena, Cesari, Matthew, Maganti, Manjula, Zia, Aysha, Ene, Gabrielle, Ferguson, Sarah E.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Cohort study; Endometrial Neoplasms - pathology; Endometrial Neoplasms - surgery; Female; Frozen section; Frozen Sections; High grade endometrial cancer; Humans; Lymph Node Excision - methods; Lymph Nodes - pathology; Lymph Nodes - surgery; Middle Aged; Neoplasm Staging; Nodal spread; Prospective; Prospective Studies; Sentinel Lymph Node - pathology; Sentinel Lymph Node - surgery; Sentinel Lymph Node Biopsy - methods; SENTOR
• ISSN: 0090-8258; 1095-6859
• DOI: 10.1016/j.ygyno.2023.04.004

The study aimed to define the accuracy of intraoperative frozen section (FS) for the detection of metastases in sentinel lymph node biopsy (SLNB) and describe the pattern of lymph node (LN) spread and relation to molecular classifiers in patients with high-grade endometrial cancer (EC). We performed a secondary outcome of clinicopathologic data from the Sentinel Lymph Node Biopsy versus Lymphadenectomy for Intermediate- and High-Grade Endometrial Cancer Staging (SENTOR) prospective cohort study evaluating SLNB in patients with clinical stage I high-grade EC (ClinicalTrials.gov ID: NCT01886066). The primary outcome was the sensitivity of FS of the sentinel lymph node (SLN) specimen, compared to a standardized ultrastaging protocol. Secondary outcomes included the pattern and characteristics of LN spread. There were 126 patients with high-grade EC with a median age of 66 years (range:44–86) and a median Body Mass Index (BMI) of 26.9 kg/m2 (range:17.6–49.3). FS was performed on surgical specimens from 212 hemipelves; SLNs were identified in 202 specimens (95.7%) and fatty tissue alone was identified in 10 specimens (4.7%). Of the 202 hemipelves in which SLNs were identified, 24 were positive for metastatic disease on final pathology. Initial FS correctly identified only 12, yielding a sensitivity of 50% (12/24, 95% CI 29.6–70.4) and a negative predictive value of 94% (178/190, 95% CI 89–96.5). A total of 24 patients (19%) had LN metastases: 16 (13%) had isolated pelvic metastases, 7 (6%) had both pelvic and para-aortic metastases and 1 (0.8%) had an isolated para-aortic metastasis. Intraoperative FS of SLNs in high-grade EC patients has poor sensitivity. Since isolated para-aortic metastases are rare, para-aortic lymphadenectomy may be omitted in patients in which SLNs were successfully mapped to the pelvis. •Sensitivity of intraoperative frozen section of the SLNB in high-grade EC is 50% (95% CI 29.6–70.4).•The rate of occult LN metastases in clinical stage I high-grade EC is 19% (95% CI 12.6–27).•The rate of occult isolated para-aortic metastases in high-grade EC is 0.8% (95% CI 0–4.3).