2017 Section 7 Green Book

Cheung et al

Figure 6. Forest plots of sensitivity and specificity for positron emission tomography and positron emission tomography/computed tomo- graphy in the diagnosis of distant metastases in recurrent head and neck squamous cell carcinomas.

Timing before 12 weeks versus after 12 weeks. Studies that had scans performed both before and after the 12-week cutoff were excluded from the subgroup analysis. The speci- ficity was significantly higher for scans performed more than 12 weeks after treatment for both local and nodal recurrence ( P = .009 and P = .0043, respectively). There was no significant difference found in the sensitivity of scans ( Table 2 ). Discussion The aim of our meta-analysis was to evaluate the diagnostic accuracy of PET and PET/CT for the detection of residual and/or recurrent disease in the post-(chemo)radiotherapy set- ting. We found that PET and PET/CT were highly accurate in the detection of residual and/or recurrent disease at local, nodal, and distant sites, although the timing of the scan did have an impact on the accuracy of such scans. PET/CT was more specific than PET alone in the detection of disease at the primary site. However, no difference was found between scans that were interpreted visually compared with those ana- lyzed semiquantitatively using standard uptake values. While there have been previous meta-analyses summariz- ing the diagnostic accuracy of PET and PET/CT in the detection of recurrences at locoregional 38,39 and distant 40 sites, these reviews have included retrospective as well as prospective studies, and this may overestimate the diagnos- tic test accuracy by introducing bias. Moreover, the meta- analysis by Gao et al 40 included patients with head and neck cancers, not specifically SCCs, while the study by Isles et al 39 included data on dual-head gamma detection systems that have inferior resolution compared with dedi- cated full-ring PET scanners.

69.82; Figure 7 ). The AUC was 0.93 (standard error 0.02) with a Q * index of 0.86 (standard error 0.02). Meta-regression Analysis On univariate meta-regression analysis, sample size, QUADAS score, imaging type, timing of posttreatment scan, and method of image interpretation did not affect the diagnostic odds ratio for detection of local, nodal, or overall tumor recur- rence (all P values . .05). There were insufficient data to assess the impact of the initial tumor site and clinical pre- sentation at recurrence on test accuracy. Because of the limited number of studies reporting on the detection of dis- tant recurrences, the effect of these factors on test accuracy could also not be assessed. Subgroup Analysis Subgroup analysis could not be performed for studies evalu- ating the detection of distant metastases as there were insuf- ficient studies. PET versus PET/CT. PET/CT was found to be more specific than PET alone in the detection of residual/recurrent disease at the primary site ( P \ .001). No significant difference in sensitivity was noted between the 2 modalities for local recurrence ( P = .07). There was no statistical difference in the sensitivity or specificity between studies using PET to detect residual/recurrent disease at neck sites compared with those using PET/CT ( Table 2 ). Visual vs semiquantitative analysis. No statistical difference was found in the sensitivity or specificity between visual and semiquantitative analysis of scans for the detection of disease at the primary site or in the neck ( Table 2 ).

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