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Imaging in endometrial cancer

https://doi.org/10.1016/j.bpobgyn.2014.04.007Get rights and content

The prognosis for women with endometrial cancer is generally good. This is because the disease is often diagnosed at an early treatable stage, as women seek care owing to postmenopausal bleeding. The prognosis is, however, worse for women with high-risk endometrial cancer. These women may benefit from more extensive surgery, including pelvic- and para-aortic lymph-node dissection, whereas such surgery is of no benefit for women with low-risk cancer. It is, therefore, important to correctly identify women with high-risk cancer before surgery. No consensus has been reached on how and when to use imaging to assess local extension of the disease. Nevertheless, evidence shows that imaging will improve the identification of women with high-risk cancer. The primary aim of this review is to present the examination technique, accuracy, imaging findings, benefits, and shortcomings of ultrasound and magnetic resonance imaging in the assessment of local tumour extension, in women with endometrial cancer. A secondary goal is to discuss the role of positron emission tomography and computed tomography, diagnostic modalities that primarily are used to detect lymph node and distant metastasis.

Section snippets

Epidemiology

Endometrial cancer is the most common gynaecological malignancy in industrialised countries [1]. Incidence differs between rural and urban populations and across countries, indicating that lifestyle has an effect [2]. Excess weight alone is estimated to cause around 50% of all endometrial cancer cases in Europe and the USA [3].

Peak incidence is around 65 years, 90% of the cases being diagnosed in postmenopausal women, and most women seeking care owing to postmenopausal bleeding (PMB). Prognosis

Examination technique and the use of different ultrasound modalities in the assessment

To properly assess all aspects related to tumour evaluation in women with endometrial cancer, a high-end ultrasound system should preferentially be used, with a two-dimensional or three dimensional 3–5 to 9–10 MHz transvaginal transducer. In some women with endometrial cancer, the image quality is simply too poor for any assessment, even for a skilled examiner using high-end ultrasound equipment. Poor image quality is often related to adiposity, which is a common finding in women with

Objective measurement techniques

Only a few studies have been published on objective measurement techniques to assess myometrial invasion. Two studies concluded that the tumour–uterine anterio–posterior ratio is the most favourable objective measurement *[22], [43] to predict deep myometrial invasion, with an optimal cut-off of 0.5–0.53, and an accuracy similar to that of subjective assessment [22]. In another study [19], tumour-free minimal margin was measured on the saved three-dimensional volume, using a 9-mm cut-off (i.e.

Computed tomography and positron-emission tomography combined with computed tomography in the assessment of endometrial cancer

Computed tomography is widely available and less expensive than MRI, and provides fast reproducible image acquisition. It has a high mutiplanar spatial resolution, which uses multi-detector equipments that are standard today. A clear advantage of using computed tomography is the ability to completely survey the entire pelvis, abdominal cavity, and thorax for local and distant tumour staging. Intravenous contrast improves the evaluation of vascularised structures and the detection of lesions in

Magnetic resonance imaging in the assessment of endometrial cancer

Magnetic resonance imaging is a unique imaging modality in the way multi-planar images are generated. These images can be acquired with high temporal, contrast and spatial resolution of any part of the body, including the pelvis, using radio-frequency waves, a shielded room, and a scanner with a strong and homogeneous magnetic field. The challenge when using MRI is to use the wide capacity of the technique optimally, which allow images to be created based on an unlimited number of combinations

Dynamic contrast-enhanced magnetic resonance imaging

At the end of the magnetic resonance examination, a contrast agent is administered intravenously. This contrast agent is a gadolinium-based chelate that will enhance the signal intensity in perfused tissues. Imaging of the same body part after injection is repeated at pre-defined intervals is usually referred to as dynamic contrast-enhanced MRI (DCE-MRI). The rationale behind the contrast-enhanced sequence in uterine cancer is to improve delineation of the tumour to the myometrium based on

Diffusion-weighted imaging

A magnetic resonance imaging technique that has become widely and increasingly used in oncology during the past decade is diffusion-weighted MRI. Diffusion-weighted imaging is based on magnetic resonance measurement of random extra- intra- and transcellular movement of water molecules in the body. As some tissues in the body have more restricted diffusion than others, this offers a way of receiving information about tissues on a cellular level. Many solid tumours tend to have more restricted

Lymph-node metastases

The major limitations with imaging for detecting lymph-node metastases includes the limitations of using size criteria alone as thresholds for identifying metastatic nodes based on enlargement of lymph nodes infiltrated by cancer. A common threshold for retroperitoneal lymph nodes is where those greater than 10 mm in shortest transverse diameter are considered as metastatic. These size criteria were also use in three out of the four studies that showed similar diagnostic accuracy for MRI and

Conclusion

Despite lack of consensus, imaging today is increasingly used for preoperative identification of women who are at high risk of endometrial cancer, so that surgery can be individually tailored, and healthcare resources optimally used. High-risk cancer is defined as the presence of deep myometrial invasion, cervical stromal invasion, or high grade tumours. The final assessment of tumour extension is by histological assessment of the hysterectomy specimen. Several studies have shown that

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