CT Colonography for Early Detection of Peritoneal Metastasis in Patients with Gastric Cancer

Take-Away Points

• ■ Major Focus: To assess diagnostic feasibility of CT colonography (CTC) for early detection of peritoneal metastasis (PM) in patients with gastric cancer.

• ■ Key Result: CTC detected PM with 83% (10 of 12) sensitivity and 100% (six of six) specificity.

• ■ Impact: Earlier detection of PM may improve prognosis in patients with gastric cancer.

PM, one of the most common forms of gastric cancer recurrence, is associated with poor patient prognosis. Previous studies using noninvasive imaging methods, including CT and endoscopic US, to detect PM demonstrated low accuracy. CTC may provide higher sensitivity for PM detection and is less invasive than conventional colonoscopy.

In this prospective cohort study, CTC was performed in 18 patients with gastric cancer and PM that was suspected on the basis of abnormal clinical symptoms and signs of PM at conventional CT, including thickening of the intestinal wall and mesentery and presence of ascites. CTC helped detect PM in 10 patients (56%) and helped identify colonic deformities at locations different from those observed at CT in seven patients. CTC achieved higher accuracy, sensitivity, and specificity for PM detection compared with CT alone (90% [16 of 18] vs 61% [11 of 18], 83% [10 of 12] vs 75% [nine of 12], and 100% [six of six] vs 33% [two of six], respectively). Median overall survival was shorter in patients with findings positive for PM at CTC compared with those with negative findings at CTC (201 days [95% CI: 29, 495] vs 945 days [95% CI: 386, not applicable], respectively; P = .01), and multivariate analysis showed positive PM findings at CTC as the only determined factor to be independently associated with survival (P = .005).

This study suggests the diagnostic and prognostic value of CTC for early detection of PM in gastric cancer. Larger prospective studies are needed to validate use of CTC as an alternative to conventional imaging.

Highlighted Article

• Iwasaki K, Cho H, Maezawa Y, et al. Assessment of the use of computed tomography colonography in early detection of peritoneal metastasis in patients with gastric cancer: a prospective cohort study. PLoS One 2022;17(1):e0261527. doi: https://doi.org/10.1371/journal.pone.0261527.