False negative rate at 18F-FDG PET/CT in para-aortic lymphnode involvement in patients with locally advanced cervical cancer: impact of PET technology

Marie Terroir,Cyrus Chargari,Philippe Morice,Catherine Genestie,Alexandra Leary,Sebastien Gouy,Patricia Pautier,Amandine Maulard,Anna Ilenko,Veronika Seebacher,Désirée Deandreis,Serena Grimaldi

doi:10.1186/s12885-021-07821-9

Abstract

BackgroundThe identification of factors responsible for false negative (FN) rate at 18F- Fluorodeoxyglucose (FDG) Positron Emission Tomography /Computed Tomography (PET/CT) in para-aortic (PA) lymph nodes in the presurgical staging of patients with locally advanced cervical cancer (LACC) is challenging. The aim of this study was to evaluate the impact of PET/CT technology.MethodsA total of 240 consecutive patients with LACC (International Federation of Gynecology and Obstetrics, FIGO, stage IB2-IVA) and negative Magnetic Resonance Imaging (MRI) and/or Computed Tomography (CT) and negative 18F-FDG PET/CT in the PA region, undergoing laparoscopic PA lymphadenectomy before chemoradiotherapy were included. The FN rate in patients studied with Time of flight (TOF) PET/CT (TOF PET) or non-Time of flight PET/CT (no-TOF PET) technology was retrospectively compared.ResultsPatients presented with FIGO stage IB (n = 78), stage IIA-B (n = 134), stage III (n = 18) and stage IVa (n = 10), squamous cell carcinoma (n = 191) and adenocarcinoma (n = 49). 141/240 patients were evaluated with no-TOF PET/CT and 99/240 with TOF PET/CT. Twenty-two patients (9%) had PA nodal involvement at histological analysis and considered PET/CT FN findings. The FN rate was 8.5% for no-TOF PET and 10% for TOF PET subgroup respectively (p = 0.98). Ninety patients (38%) presented with pelvic node uptakes at PET/CT. The FN rate in the PA region was 18% (16/90) and 4% (6/150) in patients with and without pelvic node involvement at PET/CT respectively (19 vs 3% for no-TOF PET and 17 vs 5% for TOF PET subgroup).ConclusionsIn LACC, FN rate in PA lymph nodes detection is a clinical issue even for modern PET/CT, especially in patients with pelvic uptake. Surgical lymphadenectomy should be performed in case of negative PET/CT at PA level in these patients, while it could be discussed in the absence of pelvic uptake.

Highlights

The identification of factors responsible for false negative (FN) rate at 18F- Fluorodeoxyglucose (FDG) Positron Emission Tomography /Computed Tomography (PET/CT) in para-aortic (PA) lymph nodes in the presurgical staging of patients with locally advanced cervical cancer (LACC) is challenging
The aim of this study is to determine the impact of Time of Flight (TOF) PET/CT vs no-TOF PET/CT technology on false negative rate in PA lymph node detection in the presurgical staging of patients with LACC
TOF vs no-TOF PET/CT analysis In relation to PET tomograph technology, 141/240 patients were evaluated with no-TOF PET/CT (73 at Gustave Roussy (GR) and 68 in other centers) and 99/240 with TOF PET/CT (45 at GR and the remaining 54 in other centers)

Summary

Introduction

The identification of factors responsible for false negative (FN) rate at 18F- Fluorodeoxyglucose (FDG) Positron Emission Tomography /Computed Tomography (PET/CT) in para-aortic (PA) lymph nodes in the presurgical staging of patients with locally advanced cervical cancer (LACC) is challenging. In patients with LACC, high false negative rate for PET/CT in detecting metastatic PA lymph nodes has been reported in several published studies [7,8,9,10,11]. For this reason, surgical staging is still considered in patients with negative presurgical 18F-FDG PET/CT at PA level [12]. The introduction of Time of Flight (TOF) technique using crystal materials with relatively high time resolution should theoretically increase the sensitivity and lesion detectability [13,14,15]

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