Diagnostic value of 18F-FDG PET/CT as first choice in the detection of recurrent colorectal cancer due to rising CEA

Abstract

BackgroundThe diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) as the first imaging approach in the evaluation of rising carcinoembryonic antigen (CEA) is not clear. The objective of this study was to investigate the value of 18F-FDG PET/CT in patients with colorectal cancer (CRC) and suspected recurrence based on rising CEA.MethodsA total of 73 patients with CRC were referred to PET/CT after radical surgery. Generally, all patients were scheduled to follow a CT-based post-surgical follow-up regimen. In the case of rising CEA, 18F-FDG PET/CT was performed in most patients with contrast-enhanced CT. The PET/CT images were independently reviewed by two readers. The presence or absence of recurrence was based on histology and/or standardized clinical follow-up.ResultsAmong 35 patients who had confirmed recurrence of CRC, PET/CT demonstrated recurrence with a sensitivity of 85.7 %, a specificity of 94.7 %, a positive predictive value of 93.8 %, and a negative predictive value of 87.8 %. The SUVmax ranged from 1.3 to 19.9. The mean time since the last postoperative imaging and PET/CT was 8 months (median 4 months). CEA values at referral ranged from 1.5 to 164.0 μg/L (median 5.6 μg/L). The diagnostic properties of PET/CT were analyzed in subgroups of patients with a single rising CEA sample (30 patients, 41 %), 31 patients (43 %) with two or more consecutive increases, and 12 patients (16 %) with persistently elevated values.Conclusions18F-FDG PET/contrast-enhanced CT has high diagnostic accuracy in the diagnosis of recurrent CRC, even in patients in a conventional CT-based follow-up program.

Evaluation of recurrent disease in the re-staging of colorectal cancer by 18F-FDG PET/CT: Use of CEA and CA 19–9 in patient selection

“…As a last aspect, in addition to the absolute CEA and CA 19-9 levels, the pattern of rise of these biomarkers over time appears as a relevant index in patient selection (12). A recent study concluded that patients with a single large increase in CEA may be referred directly for PET, whereas a minor increase led to referral only when the increasing trend had been confirmed in further assays (12).…”

“…A recent study concluded that patients with a single large increase in CEA may be referred directly for PET, whereas a minor increase led to referral only when the increasing trend had been confirmed in further assays (12). The use of serum biomarkers kinetics indexes such as 'velocity' and 'doubling time' has proven to be a significant advance in the selection of patients undergoing PET/CT in the restaging of other oncological diseases, such as prostate cancer (28).…”

“…Therefore, in common clinical routine, fl uorodeoxyglun common clinical routine, fluorodeoxyglucose (2-deoxy-2-( 18 F)fluoro-D-glucose; 18 F-FDG) positron emission tomography/computed tomography (PET/CT) has a major role in the assessment of recurrent CRC (8)(9)(10)(11)(12). PET/CT has the ability to detect cancer via the evaluation of tissue metabolism, which is pathologically increased prior to the appearance of morphological changes.…”

Survival Outcomes in Asymptomatic Patients With Normal Conventional Imaging but Raised Carcinoembryonic Antigen Levels in Colorectal Cancer Following Positron Emission Tomography-Computed Tomography Imaging

“…Although an individual series suggested that FDG PET-CT had high diagnostic accuracy, with sensitivity and specificity of 85.7% and 94.7% respectively, FDG PET-CT was used as a primary imaging tool in that study when patients were found to have raised CEA levels [27]. This study therefore had two major limitations: (a) The superiority of FDG PET-CT over conventional investigations could not be established, and (b) there was limited information on patients with occult disease and normal results on conventional investigations.…”

SNMMI Comment on the 2016 Society of Surgical Oncology “Choosing Wisely” Recommendation on the Use of PET/CT in Colorectal Cancer

“…In particular, in a retrospective study by Choi et al on 245 colorectal cancer patients who underwent CE CT and PET/CT as part of routine follow-up after resection with curative intent, PET/CT was found to detect more sites of recurrent disease than CE CT (12). Further, Gade et al, Mittal et al, and Metser et al found that in patients with previously resected colorectal cancer and clinically suspected recurrence, lesion detection was significantly higher with PET/CT (on the order of 15%-30%) than with CE CT (13)(14)(15).…”