[18F]FDG-PET or PET/CT in the evaluation of pelvic and para-aortic lymph nodes in patients with locally advanced cervical cancer: A systematic review of the literature

Purpose: Imaging is essential in detecting lymph node metastases for radiotherapy treatment planning in locally advanced cervical cancer (LACC). There are not many data on the performance of [18F]FDG-PET(CT) in showing lymph node metastases in LACC. We pooled sensitivity and specificity of [18F]FDG-PET(CT) for detecting pelvic and/or para-aortic lymph node metastases in patients with LACC. Also, the positive and negative posttest probabilities at high and low levels of prevalence were determined. Methods: MEDLINE and EMBASE searches were performed and quality characteristics assessed. Logit-sensitivity and logit-specificity estimates with corresponding standard errors were calculated. Summary estimates of sensitivity and specificity with corresponding 95% confidence intervals (CIs) were calculated by anti-logit transformation. Positive and negative likelihood ratios (LRs) were calculated from the mean logit-sensitivity and mean logit-specificity and the corresponding standard errors. The posttest probabilities were determined by Bayesian approach. Results: Twelve studies were included with a total of 778 patients aged 10–85 years. For pelvic nodes, summary estimates of sensitivity, specificity, LR+ and LR- were: 0.88 (95%CI: 0.40–0.99), 0.93 (95%CI: 0.85–0.97), 11.90 (95%CI: 5.32–26.62) and 0.13 (95%CI: 0.01–1.08). At the lowest prevalence of 0.15 the positive predictive value (PPV) and negative predictive value (NPV) were 0.68 and 0.98, at the highest prevalence of 0.65, 0.96 and 0.81. For the para-aortic nodes, the summary estimates of sensitivity, specificity LR+ and LR- were: 0.40 (95%CI: 0.18–0.66), 0.93 (95%CI: 0.91–0.95), 6.08 (95%CI: 2.90–12.78) and 0.64 (95%CI: 0.42–0.99), respectively. At the lowest prevalence of 0.17 the PPV and NPV were 0.55 and 0.88, at the highest prevalence of 0.50, 0.86 and 0.61. Conclusion: The PPV and NPV of [18F]FDG-PET(CT) showing lymph node metastases in patients with LACC improves with higher prevalence. Prevalence and predictive values should be taken into account when determining therapeutic strategies based on [18F]FDG-PET(CT).