Abstract
Background: Colorectal cancer (CRC) is the third most common cancer in men and the second in women worldwide, the current treatment for localized CRC is curative complete surgical resection after exclusion of distant metastases, Unfortunately, high recurrence rate was recorded post-operatively within 5 years. Early detection of recurrent CRC has become more important, as the treatment options for localized recurrence disease have improved significantly. Objective: to evaluate the role of PET/CT in postoperative evaluation of suspected recurrence or metastases in CRC patients in comparison with CECT. Methods: Between December 2018 and December 2019, twenty patients with histopathologically proven colorectal primary malignancy were evaluated for suspected local recurrence and metastasis. No age predilection and both sexes were included, medical, clinical history, any other follow up images, tumor markers (CEA), and pathological reports were reviewed for gold standard. Results: Local recurrence detected in 10 patients by PET/CT with 90% sensitivity, 90% specificity, 90% accuracy, 90% PPV and 90% NPV and detected in 9 patients by CECT with sensitivity 72.7%, specificity 88.8%, accuracy 80.0%, PPV88.8% and NPV 72.7%. While distant metastasis to different organs detected in 15 patients by PET/CT with sensitivity 87.5%, specificity 75%, accuracy 85%, PPV93.3%, NPV 60 % and detected in 12 patients by CECT with sensitivity 68.7%, specificity 75%, accuracy 70 %, PPV 91.6% and NPV 37.5%. PET/CT imaging detected 1 recurrent and 12 metastatic lesions that were missed by CECT. Conclusion: PET/CT is an advanced diagnostic imaging technique in detecting loco-regional recurrence and metastasis.