Application of transrectal three-dimensional ultrasound for sub-staging of locally advanced rectal cancer at stage T3.

OBJECTIVE: To evaluate the value of transrectal three-dimensional ultrasound (3D-TRUS) in the T3 sub-staging of locally advanced rectal cancer. METHODS: A retrospective analysis was conducted on patients with non-metastatic T3 stage rectal cancer who were diagnosed and treated at Fujian Cancer Hospital from December 2021 to December 2025. Preoperative T3 sub-staging data obtained via 3D-TRUS were compared with those obtained from the current standard magnetic resonance imaging (MRI) findings. The sensitivity, specificity, and Kappa statistic of the ultrasound method were evaluated. RESULTS: A total of 174 patients were included, achieving a lesion detection rate of 100%. 3D-TRUS demonstrated substantial agreement with magnetic resonance imaging (MRI) for determining T3 sub-staging (Kappa = 0.734, p < 0.001), with a specificity at 90.4%, a sensitivity at 83.3%, and an overall accuracy at 73.7%. CONCLUSION: 3D-TRUS demonstrates high accuracy in T3 sub-staging of locally advanced rectal cancer and offers a high-resolution, practical option for the clinical management of locally advanced rectal cancer.