| Chapter 1 Comparison of the value of 18F-NOTA-FAPI-04 PET/CT and enhanced CT for pre-radiotherapy evaluation of patients with locally advanced esophageal squamous carcinoma based on pathologyBackground:Accurate pre-treatment evaluation,including tumor length and lymph node metastasis,is of great significance for the treatment of locally advanced esophageal squamous carcinoma(ESCC).Objective:To compare the diagnostic value of 18F-NOTA-FAPI-04 PET/CT with that of enhanced CT in assessing lesion length and lymph node metastasis in patients with locally advanced ESCC.Methods:Eleven patients with locally advanced esophageal squamous carcinoma who received surgery were enrolled from June to August 2021.All patients underwent 18F-NOTA-FAPI-04 PET/CT imaging and enhanced CT imaging one week before treatment.The lesion length was measured directly on enhanced CT,and the primary foci were outlined at SUVmax thresholds of 20%,30%,40%,50%,60%,and 70%on 18F-NOTA-FAPI-04 PET images and the lengths were measured separately.The length of the primary foci measured on 18F-NOTA-FAPI-04 PET and enhanced CT were compared with the pathologic length,which was regarded as the gold standard.In addition,the sensitivity and specificity of 18F-NOTA-FAPI-04 PET/CT versus enhanced CT in the diagnosis of metastatic lymph nodes in esophageal cancer were compared.Results:The length measured on CECT was also consistent with the pathological length(Spearman rho=0.745,P=0.009).The length of esophageal cancer outlined on 18F-NOTA-FAPI-04 PET using 20%or 30%SUVmax as a threshold was not significantly different from the pathological length(P=0.159,0.689)with correlation coefficients of 0.560 and 0.723.The sensitivity,specificity and accuracy of 18F-NOTA-FAPI-04 PET/CT for the diagnosis of lymph node metastasis were 36.36%,99.20%and 96.54%compared with 54.55%,98.39%and 96.54%for enhanced CT,respectively.No significant differences were seen in the diagnostic efficacy of the two methods for detecting metastatic lymph nodes.In terms of lymph node staging,the accuracy of 18F-NOTA-FAPI-04 PET/CT was 63.64%,which was slightly better than that of enhanced CT at 54.55%,but not statistically different.Conclusion:On 18F-NOTA-FAPI-04 PET/CT,30%SUVmax can be used as the optimal threshold for assessing the length of esophageal cancer lesions.In the diagnosis of metastatic lymph nodes,18F-NOTA-FAPI-04 PET/CT had no significant advantage over enhanced CT,but was slightly better than enhanced CT in N staging.Chapter 2 Use of 18F-NOTA-FAPI-04 PET/CT to predict pathologic response to neoadjuvant chemoradiotherapy in esophageal squamous carcinomaBackground:In esophageal squamous carcinoma(ESCC),a pathologic complete response(pCR)to neoadjuvant chemoradiotherapy(nCRT)was related to long-term survival and might influence the following decision of esophagectomy or organ-preserving strategy.The role of 18F-NOTA-FAPI-04 PET/CT in predicting pathologic response after nCRT remains unclear.Objective:This study aims to evaluate whether 18F-NOTA-FAPI-04 PET may predict the pathologic complete response to neoadjuvant chemoradiotherapy(nCRT)in esophageal squamous cell carcinoma(ESCC).Methods:16 patients with ESCC who received nCRT were enrolled in this prospective study.All patients underwent an 18F-NOTA-FAPI-04 PET/CT scan before nCRT.A total of 14 patients received surgery.The primary tumor was semi-automatically delineated using a threshold of 30%maxim standardized uptake value(SUVmax).Parameters of PET imaging were extracted and compared between the complete pathologic response(pCR)group and the non-pCR group.The usefulness of significant features in predicting pathologic tumor response to nCRT was evaluated using the area under the receiver operating characteristic curve(AUC).Result:Histopathologic evaluation of surgical samples after neoadjuvant radiotherapy revealed that six of fourteen patients had a pCR.The pCR group showed statistically significantly higher TBRmax and TBRmean than the non-pCR group(TBRmax:19.34±6.13 vs.11.49±4.89,P=0.02;TBRmean:10.91±3.46 vs.6.35±2.68,P=0.017).In receiver operating characteristic analysis,TBRmax and TBRmean were significant predictors for pCR with the AUC of 0.875 or 0.896(cut-off value:12.44 or 6.9,respectively).Conclusion:18F-NOTA-FAPI-04 PET/CT might predict the pathologic tumor complete response to neoadjuvant chemoradiotherapy in patients with ESCC and TBRmax,TBRmean be valuable predictors. |
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