18FDG-PET/CT versus Contrast enhanced CT in detection of loco-regional Breast Cancer Recurrence Alnouby. A, 2Ali. I, 3Nasr. I, 4Rezk. M, 5Elwan. A, 6Abdelkader H. 1Nuclear Medicine-Unit, International Medical Center. 2Radiology Department, Faculty of Medicine , Zagazig University,, 2,5Oncology and Nuclear Medicine Department, Faculty of Medicine , Zagazig University, ,4Radiology Department, National Cancer Institute, Cairo University, 6Oncology and Nuclear Medicine Department, Faculty of Medicine , Helwan University Egyptian J. Nucl. Med., Vol. 15, No. 2, December 2017 Abstract Background: Among women cancer, cancer breast represents the most common type and the second cause of death related to malignancy. During the first 2 to 3 years after treatment the loco-regional recurrence rate is highest and then it decreases gradually. FDG PET/CT has high sensitivity and specificity in detection of breast cancer recurrence. Aim: Evaluation of the role of PET/CT compared to CECT in detection of loco regional recurrence in breast cancer patients during restaging and follows up. Material and Methods: Fifty seven female patients with treated breast cancer were included in this study. All patients underwent estimation of breast tumor markers levels, whole body FDG PET–CT and contrast enhanced CT (CECT). Correlation with the histopathological examination of the loco regional lesions was done. Results: Fourteen patients 14/57 (24.56%) had loco-regional recurrences most of them were hormone receptor positive and had high levels of tumor markers out of them, 2/14 patients (14.28 %) had regional recurrence, 2/14 patients (14.28%) had local recurrence (LR) with distant metastases (DM) and 10/14 patients (71.42%) had both local and regional recurrence. PET-CT detected loco-regional recurrence in 13/14 patients versus 6/14 patients for CECT. The sensitivity, specificity, PPV, NPV of both PET-CT and CECT were 92.9%, 93.0%, 81.25%, and 97.5% versus 42.9%, 100%, 100% and 84.3% respectively. PET-CT had higher sensitivity than CECT with statistically significant difference (P value 0.00001), while CECT had higher specificity with no statistically significant difference (P value 0.61). Conclusion: FDG-PET/CT is very sensitive compared to CECT in the detection of loco- regional recurrence of breast cancer. It has higher detection rate of metastatic lymph nodes. Key words: Breast cancer, local recurrence, FDG PET/CT, CECT.