Diagnostic Accuracy of 18F-FDG PET/CT in Detection of Local Recurrence in Rectal Cancer and the Added Value of Dual Time Point Scanning | ||||
| Egyptian Journal Nuclear Medicine | ||||
| Article 3, Volume 8, Issue 8, December 2013, Page 15-29 PDF (589.56 K) | ||||
| Document Type: Original Paper, Oncology | ||||
| DOI: 10.21608/egyjnm.2013.5457 | ||||
 View on SCiNiTO | ||||
| Author | ||||
Husssien Farghaly  
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| Professor of Nuclear Medicine, Faculty of Medicine, Assuit University. | ||||
| Abstract | ||||
| Objectives: To assess diagnostic accuracy of FDG PET/CT and the added value of dual time point PET/CT (DTP) in detection of local recurrence (LR) in patients with rectal cancer (RC). Methods: Patients (n = 50, 41 males and 9 female, mean age 52 ± 11 years). All patients underwent resection ± chemotherapy and/or radiotherapy. 37 patients were suspicious for LR on contrast enhanced CT (ce CT). All patients underwent whole body FDG PET/CT scan. In 18 patients 2 hours delayed pelvic PET/CT images were done. SUVmax cut off of 3.0 was set to differentiate benign from malignant lesions based on ROC analysis. Suspicious pelvic lesions were correlated with biopsies in 28 patients (56%) and with clinical and/or imaging follow-up (FDG PET/CT, CT or MRI) in 22 patients (44%). Sensitivity, specificity, positive and negative predictive values, and accuracy in detection of LR using ce CT data and following PET/CT were calculated. Results: Nine patients had LR (18%). SUV max was higher in all patients with LR. Sensitivity specificity, PPV, NPV, and accuracy for detecting recurrent lesions were significantly higher for PET/CT and PET/CT with tumor markers versus ce CT (p<0.05). Delayed pelvic PET/CT revealed increase in delayed SUV max (ΔSUV max >0) in 4/18 patients with confirmed LR (true positive) and revealed increase in delayed SUV max (ΔSUV max >0) 4/18 with no evidences of LR (false positive) while 10/18 showed decrease in SUV max (ΔSUV max ≤0) in delayed images with confirmed no LR (true negative). The combined early SUVmax and delayed increase in SUVmax revealed improvement in overall accuracy compared to either parameter alone. Conclusions: PET/CT has an excellent sensitivity and a higher overall accuracy for detection of local rectal cancer recurrence when compared to ce CT. Delayed PET/CT when performed is capable of improving the specificity, PPV and accuracy of the PET/CT study. | ||||
| Keywords | ||||
| FDG PET/CT- rectal cancer- local recurrence | ||||
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