[The accuracy of FDG-PET/CT in early-stage cervical and vaginal cancers]

18F-FDG PET/MRI and 18F-FDG PET/CT for the Management of Gynecological Malignancies: A Comprehensive Review of the Literature

OBJECTIVE

Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro- D-glucose integrated with computed tomography (18F-FDG PET/CT) or magnetic resonance imaging (18F-FDG PET/MRI) has emerged as a promising tool for managing various types of cancer. This review study was conducted to investigate the role of 18F- FDG PET/CT and FDG PET/MRI in the management of gynecological malignancies.

SEARCH STRATEGY

We searched for relevant articles in the three databases PubMed/MEDLINE, Scopus, and Web of Science.

SELECTION CRITERIA

All studies reporting data on the FDG PET/CT and FDG PET MRI in the management of gynecological cancer, performed anywhere in the world and published exclusively in the English language, were included in the present study.

DATA COLLECTION AND ANALYSIS

We used the EndNote software (EndNote X8.1, Thomson Reuters) to list the studies and screen them on the basis of the inclusion criteria. Data, including first author, publication year, sample size, clinical application, imaging type, and main result, were extracted and tabulated in Excel. The sensitivity, specificity, and diagnostic accuracy of the modalities were extracted and summarized.

MAIN RESULTS

After screening 988 records, 166 studies published between 2004 and 2022 were included, covering various methodologies. Studies were divided into the following five categories: the role of FDG PET/CT and FDG-PET/MRI in the management of: (a) endometrial cancer (n = 30); (b) ovarian cancer (n = 60); (c) cervical cancer (n = 50); (d) vulvar and vagina cancers (n = 12); and (e) gynecological cancers (n = 14).

CONCLUSIONS

FDG PET/CT and FDG PET/MRI have demonstrated potential as non-invasive imaging tools for enhancing the management of gynecological malignancies. Nevertheless, certain associated challenges warrant attention.

A Review of Nuclear Medicine Approaches in the Diagnosis and the Treatment of Gynecological Malignancies

Nuclear medicine is defined as the diagnosis and the treatment of disease using radiolabeled compounds known as radiopharmaceuticals. Single-photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/computer tomography (PET/CT) based radiopharmaceuticals have proven reliable in diagnostic imaging in nuclear medicine and cancer treatment. One of the most critical cancers that also relies on an early diagnosis is gynecological cancer. Given that approximately 25% of all cancers in developing countries are a subset of gynecological cancer, investigating this cancer subtype is of significant clinical worth, particularly in light of its high rate of mortality. With accurate identification of high grade distant abdominal endometrial cancer as well as extra abdominal metastases, 18F-Fluorodeoxyglucose ([18F]FDG) PET/CT imaging is considered a valuable step forward in the investigation of gynecological cancer. Considering these factors, [18F]FDG PET/CT imaging can assist in making management of patient therapy more feasible. In this literature review, we will provide a short overview of the role of nuclear medicine in the diagnosis of obstetric and gynecological cancers.

Evaluation of Positron Emission Tomography and Contrast-Enhanced Computed Tomography Scan in Nodal Staging of Early Operable Uterine Cancers

Introduction:

In early operable stages of cervical an endometrial malignancies, surgical staging of lymph nodes is advocated as contrast-enhanced computed tomography (CECT) has limited sensitivity and accuracy. Although fluorine-18 (F-18) fluorodeoxyglucose (FDG)/positron emission tomography (PET)-CT has potential to identify subcentimeter-sized nodal metastases, higher prevalence of pelvic inflammatory disease in developing countries could result in lower accuracy. The present study was undertaken to assess the incremental value of PET scan over CECT for nodal staging before radical surgery.

Methods:

Forty-four patients with the International Federation of Gynecology and Obstetrics (FIGO) Stage IA2–IIb carcinoma cervix and 28 patients of FIGO Stage I–II carcinoma endometrium underwent F-18 FDG-PET-CECT scan. A SUV_max value >2.5 g/ml based on body weight was considered as positive. An enhancing node with >1 cm size in the shortest dimension, with loss of fatty hilum was considered positive on CT images. The histological findings were considered the gold standard against which the two modalities were compared.

Results:

All 1226 pelvic nodes were dissected, of which 65 were found to be metastatic (i.e., 5.3%). Of the 72 patients, 15 (20.83%) had pelvic nodal metastases. The overall accuracy of PET and CECT for assessment of pelvic nodal metastases was comparable (i.e., 86% vs. 85%).

Conclusion:

PET and CECT scans have similar accuracy in pelvic nodal staging of operable uterine malignancies. Granulomatous inflammation may not be a major cause of false-positive results. The sensitivity and negative predictive values are not high enough to obviate need of surgical nodal staging.

Fluorodeoxyglucose positron emission tomography-computed tomography in evaluation of pelvic and para-aortic nodal involvement in early stage and operable cervical cancer: Comparison with surgicopathological findings

Introduction:

Nodal metastases in cervical cancer have prognostic implications. Imaging is used as an adjunct to clinical staging for evaluation of nodal metastases. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has an advantage of superior resolution of its CT component and detecting nodal disease based on increased glycolytic activity rather than node size. But there are limited studies describing its limitations in early stage cervical cancers.

Objective:

We have done meta-analysis with an objective to evaluate the efficacy of FDG PET/CT and its current clinical role in early stage and operable cervical cancer.

Materials and Methods:

Studies in which FDG PET/CT was performed before surgery in patients with early stage cervical cancers were included for analysis. PET findings were confirmed with histopathological diagnosis rather than clinical follow-up. FDG PET/CT showed lower sensitivity and clinically unacceptable negative predictive value in detecting nodal metastases in early stage cervical cancer and therefore, can not replace surgicopathological staging. False negative results in presence of microscopic disease and sub-centimeter diseased nodes are still the area of concern for metabolic imaging. However, these studies are single institutional and performed in a small group of patients. There is enough available evidence of clinical utility of FDG PET/CT in locally advanced cervical cancer. But these results can not be extrapolated for early stage disease.

Conclusion:

The current data suggest that FDG PET/CT is suboptimal in nodal staging in early stage cervical cancer.