Nodal staging contributes to risk group definition and the indication to adjuvant treatment in endometrial cancer (EC) patients. However, the role of nodal assessment evolved and requires redefinition.

Primary outcome of the study was to assess the impact of surgical nodal staging in defining HR EC. Secondary outcome was to evaluate the contribution of nodal assessment to the decision for adjuvant treatment in both HR and HIR patients submitted to surgery.

Clinical stage I-II EC patients with postoperative diagnosis of HR and HIR disease were included. The contribution of nodal staging in prognostic groups allocation was assessed by reviewing HR patients to identify those without any other feature of such class (non-endometrioid histology, p53abn immunohistochemistry, post-operative T3-T4 disease) and HIR cases to assess how nodal staging affected adjuvant treatment indication. Descriptive statistics were conducted to describe the two populations.

Fifty-seven patients were included, 46 with HR and 11 with HIR disease. Chemotherapy and external-beam radiotherapy (EBRT) were proposed in 40 HR patients. Considering histology, immunohistochemical profile and FIGO stage, high risk classification was exclusively relied on nodal involvement in 2/46 cases (4.3%). Omitting retroperitoneal staging, one of them would have been classified in the intermediate risk group and the other as HIR: without nodal staging, chemotherapy and EBRT would have been omitted in 1/40 (2.5%) case.

Among HIR patients, chemotherapy was proposed in 7/11 cases and EBRT in all cases. Adjuvant chemotherapy was indicated in 5/6 (83.3%) and omitted in 1/6 (16.7%) pN0 patient (stage Ib G2, substantial LVSI). In HIRpN0 patients, omitting nodal staging could have changed adjuvant treatment indication in 1/6 (16.7%) case. In HIRpNx patients, adjuvant chemotherapy was omitted in one patient (stage II, grade 2 and LVSI negative): nodal staging unavailability might have changed indication to chemotherapy in 1/5(20%) case, without changing indication to EBRT.

Unavailable nodal staging could globally be related to omission of chemotherapy in 2/57 (3.5%) patients and of EBRT in 1/57 (1.8%) patients.