Introduction
Cervical cancer is a common gynecological malignancy with around 569,847 new cases and 311,365 deaths annually worldwide, and a significant proportion of patients are diagnosed at a locally advanced stage.1 For locally advanced cervical cancer (LACC), concurrent chemoradiotherapy (CCRT), using cisplatin-based chemotherapy in association with pelvic external-beam radiotherapy and subsequent brachytherapy is considered the standard treatment.2Although the contribution of CCRT toward an improvement in survival outcomes and reduction in recurrence has been well confirmed, the complete clinical response of these patients is 70%–90%, and about one-third of patients with CC experience recurrence.3, 4
Accurate prediction of recurrence is of great significance. Several traditional clinical and pathological factors are identified as poor prognostic factors, which include advanced International Federation of Gynecology and Obstetrics (FIGO) stage, presence of lymph node metastasis, parametrial invasion, histological tumor type, and a large tumor diameter.5-7 However, there are still no satisfactory parameters sufficient to predict prognosis accurately.
Computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission CT (FDG PET/CT) are the most commonly used imaging modalities. Compared to CT or MRI, FDG PET/CT could show metabolic information on tumors and more accurate assessment of lymph node involvement, distant metastasis, and recurrent disease.8 Therefore, FDG PET/CT has been widely used in staging, therapeutic strategy, and treatment response assessment of patients with CC.9
With the technology developed, imaging has provided the potential of a prognostic biomarker.10 Except for the aforementioned roles, quantitative parameters derived from FDG-PET/CT, including maximum standardized uptake value (SUVmax), average SUV (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), have recently been proposed as prognostic biomarkers for patients with LACC who are treated with CCRT, but the results of studies show some extent differences. For example, Im et al. detected that the patients with high SUVmax measurement on tumor tissue had a higher risk of recurrence or progression than those with low SUVmax (HR= 2.14, 95%CI=1.08-4.22, P=0.029) ,11 but Chong et al. draw the opposite conclusion (HR=0.673, 95%CI=0.5-4.0, P=0.412) .12Therefore, we performed this meta-analysis to synthetize the relevance of FDG PET/CT parameters as prognostic biomarkers for patients with LACC who are treated with CCRT.