Elsevier

Gynecologic Oncology

Volume 108, Issue 3, March 2008, Pages 486-492
Gynecologic Oncology

Comparison of the validity of magnetic resonance imaging and positron emission tomography/computed tomography in the preoperative evaluation of patients with uterine corpus cancer

https://doi.org/10.1016/j.ygyno.2007.11.044Get rights and content

Abstract

Objective.

To compare positron emission tomography/computed tomography (PET/CT) with magnetic resonance imaging (MRI) in the preoperative detection of primary lesions and lymph node (LN) and distant metastases in patients with uterine corpus cancer.

Methods.

The patient cohort consisted of 53 women with uterine corpus cancer who underwent preoperative workup, including both MRI and PET/CT scans, and underwent surgical staging, including pelvic and/or paraaortic LN dissection, between October 2004 and June 2007 at Asan Medical Center, Seoul, Korea. Pathologic data from surgical staging were compared with the preoperative MRI and PET/CT results. For area specific analysis, LNs were divided into paraaortic, right pelvic and left pelvic areas.

Results.

In detecting primary lesions, MRI and PET/CT showed no differences in sensitivity (91.5% vs. 89.4%), specificity (33.3% vs. 50.5%), accuracy (84.9% vs. 84.9%), positive predictive value (PPV) (91.5% vs. 93.3%) and negative predictive value (NPV) (33.3% vs. 37.5%). With MRI, the sensitivity, specificity, accuracy, PPV and NPV for detecting metastatic LNs on LN area-by-area analysis were 46.2%, 87.9%, 83.9%, 28.6% and 94.0%, respectively; With PET/CT, those were 69.2%, 90.3%, 88.3%, 42.9%, and 96.6%, respectively. PET/CT showed higher sensitivity, but it did not reach statistical significance (p = 0.250). There were also no differences in specificity, accuracy, PPV and NPV. In detecting distant metastasis, the sensitivity, specificity, accuracy, PPV and NPV of PET/CT were 100%, 93.8%, 92.5%, 62.5% and 100%, respectively.

Conclusion.

In patients with uterine corpus cancer, PET/CT had moderate sensitivity, specificity and accuracy in detecting primary lesions and LN metastases, indicating that this method cannot replace surgical staging. The primary benefit of PET/CT is its sensitivity in detecting distant metastases. Because of its high NPV in predicting LN metastasis, PET/CT may also have advantages in selected patients who are poor candidates for surgical staging.

Introduction

Uterine corpus cancer is a common malignancy of the female genital tract, which is staged using the surgical staging system of the International Federation of Obstetrics and Gynecology (FIGO) [1]. The routine use and extent of lymphadenectomy has not yet been established in all patients with uterine corpus cancer. Among the methods used to preoperatively assess the presence of pelvic and paraaortic lymph nodes (LNs) are imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), but the results of these methods are not satisfactory [2], [3]. Positron emission tomography (PET), which measures the increased metabolic activity of malignant cells rather than anatomic alterations, has been expected to have higher sensitivity than MRI or CT. In cervical, ovarian and vulvar cancer, many studies defining the validity of PET in diagnosing and staging patients have been published [4]. However, the role of PET in uterine corpus cancer is less defined because of the lack of published data in the literature [4]. To overcome the lower spatial resolution of PET compared with MRI or CT, a more advanced technique, fused positron emission tomography/computed tomography (PET/CT) was introduced [5], [6]. This method combines the anatomic detail provided by CT with PET metabolic information [5], [6]. To our knowledge, however, there have been no studies of PET/CT in the preoperative evaluation of patients with uterine corpus cancer. We therefore assessed the validity of PET/CT in the preoperative evaluation of patients with uterine corpus cancer and we compared the validity parameters of PET/CT with those of MRI.

Section snippets

Study population

This clinicopathologic comparative study involved 53 patients with uterine corpus cancer who underwent a preoperative workup that included both MRI and PET/CT scans and who underwent surgical staging that included pelvic and/or paraaortic lymph node dissection between October 2004 and June 2007 at Asan Medical Center, Seoul, Korea. Their medical records were retrospectively reviewed, and surgical staging results were compared with preoperative findings on MRI and PET/CT. Initially, MRI was

Results

The patient population consisted of 53 women with uterine corpus cancer, who were diagnosed by endometrial biopsy and underwent preoperative evaluation, including both MRI and PET/CT, between endometrial biopsy and staging operation. Median patient age was 52 years (range, 27–68 years) and median body mass index was 24 kg/m2 (range, 18–40 kg/m2). Ten patients were nulliparous. The median time from endometrial biopsy to both MRI and PET/CT was 8 days (range, 1–27 days), and the median time from

Discussion

PET is a molecular imaging technique that uses radiolabeled molecules to image molecular interactions of biologic processes. Among several PET compounds available, the radiolabeled glucose analog FDG is the only tracer approved by the US Food and Drug Administration (FDA) for routine clinical use [7]. Tumor cells are associated with increased glycolysis and this metabolic property leads to increased uptake of radiolabeled FDG [8]. Although enhanced FDG uptake is not specific to malignant cells,

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