Abdominal Ultrasonography After Transrectal Filling With Contrast Agent (AU-TFCA) for the T Staging of Colon Cancer

To evaluate the diagnostic value of abdominal ultrasonography after transrectal filling with contrast agent (AU-TFCA) in the local T staging of colon cancer.

This retrospective study included patients diagnosed with colon cancer at Tianjin Third Central Hospital between April 2022 and July 2023.

Eighty-six patients (mean age 68.5 ± 9.5; 49 men) were included. The number of patients in stages T1-T4 based on pathological results was 3, 6, 64, and 13, respectively. Kappa agreement: AU-TFCA versus pathology, T3-4 = 0.585, T4 = 0.793; CECT versus pathology, T3-4 = 0.481, T4 = 0.429. ROC using lesion maximum diameter yielded optimal cutoffs of 3.35 and 4.45. AUC = 0.777 and AUC = 0.807. For detecting T3-4: sensitivity 0.779, specificity 0.778, accuracy 0.779. For T4: sensitivity 0.846, specificity 0.699, accuracy 0.721.

AU-TFCA might have higher sensitivity and specificity in preoperative T staging of colon cancer. AU-TFCA might be a valuable tool for colon cancer preoperative T staging, with a better correlation with pathology for T staging than CECT. Still, results require confirmation due to the small number of early-stage cases and the possibility of selection bias.