Elsevier

Gynecologic Oncology

Volume 128, Issue 2, February 2013, Pages 300-308
Gynecologic Oncology

MRI, PET/CT and ultrasound in the preoperative staging of endometrial cancer — A multicenter prospective comparative study

https://doi.org/10.1016/j.ygyno.2012.11.025Get rights and content

Abstract

Objectives

The aim of this prospective multicenter study was to evaluate and compare the diagnostic performance of PET/CT, MRI and transvaginal two-dimensional ultrasound (2DUS) in the preoperative assessment of endometrial cancer (EC).

Methods

318 consecutive women with EC were included when referred to three Danish tertiary gynecological centers for surgical treatment. Preoperatively they were PET/CT-, MRI-, and 2DUS scanned. The imaging results were compared to the final pathological findings. This study was approved by the National Committee on Health Research Ethics.

Results

For predicting myometrial invasion, we found sensitivity, specificity, PPV, NPV, and accuracy for PET/CT to be 93%, 49%, 41%, 95% and 61%, for MRI to be 87%, 57%, 44%, 92%, and 66% and for 2DUS to be 71%, 72%, 51%, 86% and 72%. For predicting cervical invasion, the values were 43%, 94%, 69%, 85% and 83%, respectively, for PET/CT, 33%, 95%, 60%, 85%, and 82%, respectively, for MRI, and 29%, 92%, 48%, 82% and 78% for 2DUS. Finally, for lymph node metastases, the values were 74%, 93%, 59%, 96%, and 91% for PET/CT and 59%, 93%, 40%, 97% and 90% for MRI. When comparing the diagnostic performance we found PET/CT, MRI and 2DUS to be comparable in predicting myometrial invasion. For cervical invasion and lymph node metastases, however, PET/CT was the best.

Conclusions

None of the modalities can yet replace surgical staging. However, they all contributed to important knowledge and were, furthermore, able to upstage low-risk patients who would not have been recommended lymph node resection based on histology and grade alone.

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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