Diagnostic Value of Positron Emission Tomography-Computed Tomography (PET/CT) in Detection of Recurrence after Curative resection for Colorectal Cancer

Abstract

Introduction : Accurate detection of recurrent colorectal cancer remains a diagnostic challenge. The purposes of this study were to evaluate the diagnostic value of Positron Emission Tomography-Computed Tomography (PET/CT) using fluor-18-deoxyglucose (FDG) in Detection of Recurrence after Curative resection for Colorectal Cancer. Material and Methods : We performed a retrospective review of 248 patients who underwent PET/CT for surveillance of colorectal cancer after curative resection between June 2008 and April 2011. Recurrence of colorectal cancer was validated by histopathologic examination or serial imaging study follow-up. Results : Of the 248 patients (149 males) included in the study, thirty-six patients (14.5%) were confirmed as recurrence. Liver was the most common site of recurrence (n=13). A total 472 PET/CT were conducted in 248 patients during follow-up period. The sensitivity and specificity of PET/CT were 0.921(95% CI 0.908-0.934) and 0.981(95% CI 0.975-0.987) for detecting tumor recurrence. The sensitivity and specificity of contrast enhanced computed tomography (CECT) were 0.902(95% CI 0.888-0.916) and 0.952(95% CI 0.942-0.952). CEA elevation was shown in only 13 cases (36.1%) of patients with recurrence. The treatment plans of 26 cases (10.5%) were altered by PET/CT findings. The curative surgical tumor resection procedure was performed in 15 out of 36 patients. In 3 cases which CECT showed negative findings, PET/CT had detected unexpected metachronous cancer (one colon, two bladders). Conclusions : Additional PET/CT on CECT seems to provide high detection rate of tumor recurrence after curative resection for colorectal cancer and other critical information such as unexpected secondary malignancy.