In gastric cancer patients with normal CEA level, which has better clinical impact on detection of recurrence, F-18 FDG-PET/CT or contrast enhanced abdominal CT?: According to serial pattern of CEA

Abstract

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Objectives: We aimed to assess the validity of F-18 FDG-PET/CT (PET/CT) and contrast-enhanced abdominal MDCT (CECT) for detecting recurred gastric cancer patients with normal serum CEA level (<5ng/ml) according to serial CEA patterns.

Methods: One hundred-thirty-five patients (Male 83, mean age; 59.2 y) had undergone surgery for gastric cancer and performed CEA, PET/CT and CECT for restaging. Seventy-nine patients, who had serially normal CEA level before imaging studies, were included. According to serial CEA pattern, patients were divided into 2 groups; upward pattern (UP), downward pattern (DP). Recurrence was confirmed by pathology or by clinical follow-up.

Results: Among the 79 patients, the final diagnosis of recurred gastric cancer was established in 39 lesions in 24 patients (30.4%). The diagnostic accuracy of PET/CT and CT were 83.5% and 73.4%, respectively. In each group, tumor recurrence was finally diagnosed in 48.2% (UP:27/56), 31.6% (DP: 12/38). Tumor recurrence was found more commonly in UP group. In UP group, sensitivity, specificity and diagnostic accuracy of PET/CT and CECT were 84%, 92.3%, 88.2% and 72.0%, 69.0%, 70.6%. In DP group, 50.0%, 86.2%, 74.4% and 92.8%, 75.8%, 81.4%. In UP group, the validity of PET/CT was significantly higher than CECT (p=0.03), but in DP group, there was no significant difference between PET/CT and CECT (p=0.38). In addition, PET/CT was revealed 2 distant bony metastase, 1 lung metastasis, 1 synchronous malignancy.

Conclusions: PET/CT was valuable imaging tool to detect recurrence in gastric patient with normal CEA. Specially in UP group, PET/CT revealed more higher diagnostic accuracy than CECT. In these patients, PET/CT must be recommended.