| PART ONE: Restaging, Therapeutic strategy and Prognosis of postoperative colorectal cancer: The value of 18F-FDG PET/CTObjective To evaluate the value of 18F-FDG PET/CT in restaging, therapeutic strategy and prognosis in postoperative colorectal cancer.Methods From May 2010 to June 2014, Ninty-one patients with postoperative colorectal cancer were retrospectively studied. All patients were evaluated with 18F-FDG PET/CT, the same time, sixty-six patients have CT scan. Diagnostic criteria of recurrence and metastases was the pathological diagnosis, clinical long-term follow-up(≥6 months)results combined the results of conventional imaging. The diagnostic efficiency of18F-FDG PET/CT and CT in detecting recurrence and metastases of postoperative colorectal cancer were calculated. In fifty-three patients, the results of PET/CT were true positive, and the clinical value of 18F-FDG PET/CT in restaging, therapeutic strategy and prognosis were analyzed, Kaplan-Meier survival analysis was conducted based on the results of PET/CT and the changes of therapeutic strategy before and after PET/CT.Results In fifty-five patients, recurrence and metastases were confirmed by pathology or clinical follow-up.(1)The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 18F-FDG PET/CT were 96.36%, 83.33%, 91.21%,89.93%, 93.75%, and CT were 75.00%, 84.62%, 78.79%, 88.24% and 68.75%, The sensitivity and accuracy of PET/CT were higher than CT. In PET/CT true negative group,median survival time was 10.00 years and five years survival rate was 84%, respectively,in true positive group was 6.33 years and 53%, overall survival and progression free survival time have a significant difference between two groups(Kaplan-Meier, χ2=7.753,P<0.01; χ2=8.933, P<0.01).(2) In fifty-three true-positive patients, clinical restaging was raised in thirty-two patients after PET/CT imaging, down-regulated in two patients andtherapeutic strategy were changed in thirty-three patients. Progression free survival time of patients with treatment changed were longer than that of without changed(χ2=4.905,P<0.05).Conclusion 18F-FDG PET/CT imaging has highly sensitive and accuracy in the diagnosis of recurrence and metastasis of postoperative colorectal cancer, and revise the clinical restaging and therapeutic strategy timely, and has important value for improve outcome.PART TWO: Correlation study of 18F-FDG PET/CT and CEA, CA199 in recurrence and metastases of postoperative colorectal cancerObjective To study the correlation of 18F-FDG PET/CT and CEA, CA199 in recurrence and metastases of postoperative colorectal cancer.Methods From May 2010 to June 2014, Seventy-nine patients with postoperative colorectal cancer were retrospectively studied. All patients have performed 18F-FDG PET/CT imaging and CEA, CA199 at the same period. Diagnostic criteria of recurrence and metastases was the pathological diagnosis, clinical long-term follow-up(≥6 months)results combined the results of conventional imaging. The diagnostic efficiency of18F-FDG PET/CT and CEA, CA199 in detecting recurrence and metastases postoperative colorectal cancer were calculated and contrastive analysed. Patients were divided into elevated and normal group according to the CEA, CA199 level, and the difference between two groups and the relationship between SUVmax and CEA, CA199 level were analyzed.Results In fifty patients, recurrence and metastases were confirmed by pathology or clinical follow-up. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 18F-FDG PET/CT and CEA, CA199 were 96.00%, 82.76%,91.14%, 90.57%, 92.31% and 54.00%, 96.55%, 69.92%, 96.45%, 54.90%, respectively.The sensitivity, accuracy and positive predictive value of CEA, CA199 elevated group were 100.00%, 96.43% and 96.43%%, The specificity, accuracy and negative predictive value of CEA, CA199 normal group were 100.00%, 54.90% and 54.90%. The sensitivity,specificity, accuracy, positive predictive value and negative predictive value of 18F-FDG PET/CT in CEA, CA199 elevated and group normal were 92.31%, 50.00%, 89.29%,96.00%, 33.33%, 100.00% and 85.19%, 92.16%, 85.71%, 100.00%. The detection rate of PET/CT for recurrence and metastases were 85.71%(24/28) in CEA, CA199 elevated group and 47.06%(24/51) in CEA, CA199 normal group, and has a difference between two groups(χ2=12.21,P<0.01). In CEA, CA199 elevated group, there was no correlation between CEA level and SUVmax(rs=0.216, P=0.346), and there was correlation between CA199 level and SUVmax(rs=0.861,P=0.000).Conclusion PET/CT has highly sensitive and accuracy in the diagnosis of recurrence and metastasis of postoperative colorectal cancer, and the detection rate of recurrence and metastasis in CEA, CA199 elevated group was higher than that in the normal group. CEA, CA199 elevated level has highly sensitivity and accuracy in the diagnosis of recurrence and metastasis of postoperative colorectal cancer, and CA199 elevated level has correlation with SUVmax. However, CEA, CA199 normal level can not except for recurrence and metastasis, and PET/CT should be taken into consideration in order to improve diagnostic accuracy. |
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