MRI, PET/CT and ultrasound in the preoperative staging of endometrial cancer — A multicenter prospective comparative study
Highlights
► PET/CT and MRI are equal in predicting myometrial invasion, cervical involvement and lymph node metastases in endometrial cancer patients. ► Transvaginal ultrasound has high specificity and accuracy in predicting myometrial invasion and cervical involvement in endometrial cancer patients. ► Imaging cannot replace surgical staging yet. However, the modalities may be valuable in the multidisciplinary treatment planning.
Introduction
Imaging is important in the multidisciplinary management of uterine malignancy and includes characterization and staging of tumor, treatment planning, and subsequent follow-up. Endometrial cancer (EC) is the most common uterine malignancy. The treatment of EC is primarily surgical, and the extent of surgery relies on the estimated stage and risk of extra-uterine disease. The most important risk factors for extra-uterine disease and poor outcome are depth of myometrial invasion (MI), cervical involvement (CI), tumor grade and histological sub-type, and lymph node metastases (LNM). A major obstacle is that these factors cannot be revealed by clinical examination alone. Therefore, the clinical challenge is the optimal selection of patients for more extensive surgical procedures (i.e. lymph node dissection or optimal debulking) in patients with high risk of advanced disease and relapses, while avoiding overtreatment in low-risk patients, as studies have shown that lymphadenectomy can induce complications and may not increase survival of low-risk EC patients [1], [2]. A non-invasive technique that identifies LNM and tumor-extent would be beneficial. However, optimal imaging modality and practice varies among centers and results are not in agreement [3].
Magnetic resonance imaging (MRI) is considered the most accurate imaging technique for preoperative assessment of EC because of its excellent soft-tissue contrast-resolution [4], [5]. Unlike ultrasound, MRI is not operator dependent and unlike computed tomography (CT) it has no radiation burden [6].
2-[Fluorine 18] flouro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) is a functional method based on the increased glucose-metabolism of malignant tumor cells. The potential value of PET/CT for staging of EC has not yet been established.
In expert hands, transvaginal two-dimensional ultrasound (2DUS) has shown good accuracy in local staging of EC, comparable to that of MRI performed by radiologists specialized in gynecological imaging [7].
The aim of this prospective multicenter study was to evaluate and compare the diagnostic performance of PET/CT, MRI and 2DUS in preoperative staging of EC with special focus on MI, CI and LNM.
Section snippets
Methods
Patients with a histological diagnosis of EC or atypical endometrial hyperplasia (AEH) were consecutively invited to participate in the Danish endometrial cancer study (ENDOMET). They were referred to the gynecologic clinics at University Hospitals in Copenhagen (Rigshospitalet), Odense, and Aalborg for surgery between September 1, 2009 and January 1, 2012. All participants gave informed oral and written consent. Patients with a preoperative diagnosis of AEH were included because we previously
Results
A total of 464 women with EC or AEH were referred in the inclusion period. Twenty-seven patients did not participate and 122 patients had an exclusion criterion leaving 318 patients eligible for the study. A total of 269 patients were PET/CT-scanned, 240 patients had MRI and 209 had 2DUS. 133 patients went through all three imaging modalities (Fig. 1). Median age was 65 years (range 29–94), and 282 (88.7%) were postmenopausal. Clinical characteristics are listed in Table 1. Hysterectomy was
Discussion
A non-invasive preoperative technique that accurately stages EC patients would be beneficial in improving tailored treatment and minimizing costs. The knowledge of tumor-extension influences the decision whether to perform a more radical hysterectomy with pelvic and/or paraaortic lymphadenectomy.
To our knowledge, this study is the first to compare PET/CT, MRI and 2DUS in the preoperative evaluation of EC patients. We found PET/CT and MRI to be equally good in predicting MI. 2DUS was not as
Conflict of interest statement
There are no financial disclosures or conflict of interest from any author.
Funding
Arvid Nilssons Foundation, Doctor Agnethe Løvgreens Foundation, The Danish Cancer Society, Hørslev Foundation, Harboe Foundation, Aase og Ejnar Danielsens Foundation, King Christian X Foundation, Augustinus Foundation, Dagmar Marshalls Foundation, Manufacturer Einar Willumsens Memorial Grant, Beckett Foundation & Hede Nielsens Family Foundation.
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