Diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the postoperative clinical management of patients with colorectal cancer

Abstract

Objective: Colorectal cancer (CRC) is a well-known, surgically curable type of cancer if detected early. Survival rate increase depends on the early detection of the recurrent lesions. In this present study, we aimed to emphasize the value of the F-18 FDG PET/CT imaging modality to evaluate the postoperative treatment response of patients with CRC, based on our clinical experience.
 Methods: Between January 2016 and January 2020, 168 colorectal cancer patients underwent F-18 FDG PET/CT to evaluate residue/recurrence cancer in our institution. Patients enrolled in this study were operated on for primary colon tumors. Before and after systemic therapy, all patients underwent pre and post-treatment F-18 FDG PET/CT to assess treatment response. The images were analyzed retrospectively.
 Results: Patients were classified according to primary tumor localization. Of 168 patients, the primary tumor localized in the ascending colon (n=55), the descending colon (n=33), the transverse colon (n=14), the rectosigmoid (n=61), and the caecum in the other five patients. Recurrence of primary tumor site was detected in 57 patients; 33 of them were male (57.9%) and 24 female (42.1%). The mean SUVmax of the local recurrent lesion was 8.97 ± 3.42 g/ml. In addition, from the ascending colon group, two patients had new foci of tumoral lesions (1.20%). 
 Conclusion: Resection of the colonic segments with tumor, if possible, is the first step in the treatment of patients with colorectal cancer. After the curative operation, recurrence can be seen in approximately 40% of patients within the first two years. Early detection of recurrence improves the survival rate.