Clinical Usefulness of a PET Scan in the Diagnosis of a Recurrent Colorectal Carcinoma

ABSTRACT

PURPOSE: The aim of this study was to evaluate the potential efficacy of positron emission tomography using 2- [18F]-fluoro-2-deoxy-D-glucose in detecting recurrent colorectal carcinomas. METHODS: Seventy patients suspected of having recurrent colon cancer were evaluated using PET from January 2001 to March 2003. The PET results were compared with those of computed tomography and clinical examination over 6 months. RESULTS: Among the 70 patients, 17 patients had abnormal CEA levels and no abnormal findings with conventional radiologic methods (group 1), 29 had equivocal findings on computed tomography and other radiologic studies (group 2), and 24 were proven to have recurrent colorectal carcinoma (group 3) respectively. The sensitivity and the specificity of the PET scan, which were proved to be higher then those of CT (93% vs. 72.2%, 88% vs. 48.5%), were 85.7%, and 80%, respectively, in group 1, 86.7%, and 85.7% in group 2 and both 100% in group 3. The interval between diagnosis using PET and conventional studies was 1.9 months. CONCLUSIONS: Positron emission tomography is more sensitive than computed tomography in detecting recurrent colorectal carcinomas. When conventional studies show no abnormal findings except for CEA levels, PET can be a valuable imaging tool in detecting recurrent colorectal cancer and can prevent other unnecessary exploratory procedures.