The role of ultrasound in primary workup of cervical cancer staging (ESGO, ESTRO, ESP cervical cancer guidelines)
Abstract
Objective: In 2018 three European societies have joined to create clinically relevant guidelines on the diagnosis and management of cervical cancer. The European Society of Gynaecological Oncology (ESGO), the European Society for Radiotherapy and Oncology (ESTRO), and the European Society of Pathology (ESP) agreed on diagnostic approaches in cervical cancer staging.
Design: Review article. Setting: Department of Obstetrics and Gynecology, First Faculty of Medicine, Charles University and General University Hospital in Prague.
Methods: A literature review of published data on cervical cancer staging. Results: Physical examination with biopsy still has its place in histological confirmation of malignancy but doesn't offer much information on the extent of the disease.
It is historically the first time when transvaginal/transrectal ultrasound (TVS/TRS) is recommended as an alternative to the magnetic resonance (MRI) in a primary workup. Both imaging modalities offer excellent soft tissue contrast resolution, which is crucial in tumour detection and evaluation of local extent of tumour, including the depth of tumour infiltration in the bladder and rectal wall.
These new advances in imaging rendered the use of cystoscopy and rectoscopy redundant. Similarly, with the implementation of modern imaging in pretreatment staging, intravenous urography has lost its role in the staging.
Apart from the local extent of the disease, it is necessary to accurately evaluate the lymph node status in order to plan optimal treatment. The detection rate of imaging reflects the prevalence of lymph node metastases depending on tumor stage and size of metastasis.
In the early stage disease (T1a, T1b1, T2a1) with negative lymph nodes on TVS/TRS or MRI, surgicopathological staging of pelvic lymph nodes is a method of choice for detection of small volume metastases. Both imaging modalities might not detect small metastatic lesions within non-enlarged lymph nodes, but by identifying the characteristic changes of the infiltrated lymph nodes they have very low rate of false positives.
In locally advanced cervical cancer (T1b2 and higher, except T2a1) or early stages with positive lymph nodes detected on ultrasound or MRI, computed tomography (CT) or CT in combination with positron emission tomography (PET-CT) are recommended to assess distant spread including paraaortic lymph nodes and chest. PET-CT is the preferred option in cases indicated for primary chemoradiation.
Unfortunatelly no imaging method is accurate enough to exclude small volume metastasis in paraaortic nodes. In the cases with negative paraaortic lymph nodes on CT or PET-CT, surgicopathological staging with dissection of the paraaortic lymph nodes may be considered.
In order to reduce false positive findings by imaging methods, it is recomended to obtain an ultrasound or CT-guided tru-cut biopsy from any equivocal extrauterine lesion to avoid inappropriate treatment.