Discussion of Procedures by Variant Variant 1: Initial staging of pretreatment endometrial cancer; assessment of local tumor extension for all tumor grades. Currently there is little consensus on the role of pelvic imaging in the preoperative staging of EC, with practices differing widely across centers [36]. However, when assessment of local tumour extent during initial staging is clinically indicated, this variant addresses the evidence regarding the appropriate use of the different imaging modalities. The NCCN 2020 guidelines advise MRI for initial workup as follows: to establish the origin of the tumor (endocervical versus endometrial), assess local disease extent, and exclude myometrial invasion for fertility sparing treatment [23]. In 2016, a European multidisciplinary expert panel consensus meeting on EC suggested that MRI may be useful to assess myometrial invasion in centers in which the need for lymph node dissection is based on the preoperative stratification into low-, intermediate-, or high-risk groups [37]. Preoperative risk stratification is important, because currently there is no imaging modality that can replace surgical staging, given the inability of preoperative imaging to identify small lymph node metastases, which if present will require adjuvant therapy. However, MRI is accurate at identifying two surrogate markers of lymph node metastases (eg, deep myometrial invasion and cervical stromal involvement) [38]. In the absence of these and with low-grade tumors, the risk of lymph node metastases is low [39]. In the presence of these surrogate markers, the likelihood of lymph node metastases is high enough for full surgical staging by gynecological surgeons even for low-grade tumors [9]. The role of sentinel lymph node sampling versus complete lymphadenectomy in this subgroup of patients requires further investigation [13].
Pretreatment Evaluation and Follow Up of Endometrial Cancer. Discussion of Procedures by Variant Variant 1: Initial staging of pretreatment endometrial cancer; assessment of local tumor extension for all tumor grades. Currently there is little consensus on the role of pelvic imaging in the preoperative staging of EC, with practices differing widely across centers [36]. However, when assessment of local tumour extent during initial staging is clinically indicated, this variant addresses the evidence regarding the appropriate use of the different imaging modalities. The NCCN 2020 guidelines advise MRI for initial workup as follows: to establish the origin of the tumor (endocervical versus endometrial), assess local disease extent, and exclude myometrial invasion for fertility sparing treatment [23]. In 2016, a European multidisciplinary expert panel consensus meeting on EC suggested that MRI may be useful to assess myometrial invasion in centers in which the need for lymph node dissection is based on the preoperative stratification into low-, intermediate-, or high-risk groups [37]. Preoperative risk stratification is important, because currently there is no imaging modality that can replace surgical staging, given the inability of preoperative imaging to identify small lymph node metastases, which if present will require adjuvant therapy. However, MRI is accurate at identifying two surrogate markers of lymph node metastases (eg, deep myometrial invasion and cervical stromal involvement) [38]. In the absence of these and with low-grade tumors, the risk of lymph node metastases is low [39]. In the presence of these surrogate markers, the likelihood of lymph node metastases is high enough for full surgical staging by gynecological surgeons even for low-grade tumors [9]. The role of sentinel lymph node sampling versus complete lymphadenectomy in this subgroup of patients requires further investigation [13].