Usefulness of FDG-positron emission tomography in diagnosing peritoneal recurrence of colorectal cancer

Background: Accurate detection of peritoneal recurrence in colorectal cancer remains a diagnostic challenge. We retrospectively examined sensitivity and accuracy of fluorine-18-2-fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) in the diagnosis of peritoneal recurrence. Methods FDG-PET and computed tomography (CT) were performed on 23 patients with colorectal cancer suspected of having a recurrence based on clinical symptoms, a tumor marker (CEA), and so forth. The final diagnosis was compared with the results of FDG-PET and CT. Results: Peritoneal recurrence was suspected in 6 patients with FDG-PET, and 5 of them were finally diagnosed as recurrences. The sensitivity of FDG-PET was 88% and its diagnostic accuracy was 78%, whereas those of CT were 38% and 44%, respectively. A lesion as small as 15 mm in diameter was diagnosed by FDG-PET. Conclusions FDG-PET is an effective method for diagnosing peritoneal recurrence of colorectal cancer. FDG-PET is expected to become more important for detecting peritoneal recurrence at an early stage.