Diagnostic Role Of¹⁸F-FDG PET/CT In Monitoring The Response Of Locally Advanced Breast Cancer To Neo-Adjuvant Chemotherapy: A Meta-Analysis

Background: Neoadjuvant chemotherapy is often used in the management of large,locally advanced breast cancers. Because of the difficulty in differentiating fibrosis fromresidual tumor, clinical examination, mammography and other conventional imagingmodalities are of limited use for monitoring the treatment response. PET being a metabolicimaging modality is a useful tool to demonstrate changes in tumor metabolism beforemorphologic changes occur, so unresponsive tumors can be identified quickly.Objective: To evaluate the diagnostic accuracy of¹⁸F-FDG PET in the monitoringresponse of locally advanced breast to neoadjuvant chemotherapy, a meta-analysis wasconducted from February,2011to June2011.Methods: By systematic MEDLINE and EMBASE searches supplemented by manualsearches of the references listed in original and review articles, relevant articles publishedin medical and oncologic journals between January2000and April2011were identified.The last article was searched onApril31st,2011.Selection criteria included studies that used FDG as a radiopharmaceutical, those withsufficient data to allow for the calculation of specificity and sensitivity and studies whichused an FDG-PET dedicated camera.Articles were independently reviewed by two reviewers and data on the clinicalinformation of the study patients, quality and technicality of FDG-PET imaging, PET testinterpretation, and the number of true positive and negatives and false positives andnegatives were extracted. Meta analytic methods were used to compute the summarysensitivity and specificity, false positive rate, and the maximum joint sensitivity andspecificity. Results: Eleven studies were included in the study after meeting the inclusion criteria.The total number of patients was526. Histopathology was used as the Gold standard in alleleven studies. The pooled sensitivity and specificity before exclusion of the outliers was73.0%（95%confidence interval,61.0%-72.2%） and75.2%（95%confidence interval,77.1%-88.1%）; and after exclusion of the outliers, the pooled sensitivity and specificitywas78.0%（95%CI,72.0%–86.3%） and80.0%（95%CI,72.4–86.3%）, respectively. Thepositive predictive and negative predictive values before exclusion of the outliers were86.1%and69.6%, respectively and the positive and negative likelihood ratios, anddiagnostic odd ratio were3.34,2.84and16.34, respectively. The maximum joint sensitivityand specificity, Q*, which measures the diagnostic performance of¹⁸F-FDG-PET was78.5%. After one course of chemotherapy, the pooled true positive rate and false positiverate were68.6%（95%confidence interval,58.8%–77.3%） and9.9%, respectively; andafter two courses of chemotherapy, the pooled sensitivity and false positive rate were74.8%（95%confidence interval,65.2%-82.8%） and22.5%, respectively.Conclusion: The findings suggest that¹⁸F-FDG PET is an important clinical tool inthe early detection of responders from non-responders, and clinicians should consider itsapplication in the evaluation of response to neoadjuvant chemotherapy in patients withlocally advanced breast cancer.