PURPOSE: Although noninvasive and highly informative, transabdominal ultrasonography (US) is not yet an accepted means of staging colorectal cancer preoperatively. This prospective study evaluated the diagnostic accuracy of US in preoperative staging of patients with resectable colon cancers. METHODS: A total of 98 patients with primary colon cancer diagnosed by colonoscopy at our institute between January, 2011 and June, 2014 underwent preoperative ultrasonographic tumor staging. Depth of tumor infiltration (T-stage) was assessed by standard means (i.e., extent of mural involvement), analyzing agreement in US and histopathology determinations. RESULTS: All but two colon cancers (at splenic flexure) were detected by US (98%, 96/98). Compared with histopathology, overall accuracy of US in determining T-stage was 64% (61/96), indicating moderate reproducibility (κ coefficient 0.48; 95% CI 0.35-0.62; p < 0.001). Using a three-tier approach of graded muscularis propria (MP) involvement (Tis/T1, below MP; T2, within MP; and T3/T4, beyond MP), diagnostic agreement increased to 89% (85/96), with good agreement (κ coefficient 0.77; 95% CI 0.64-0.90; p < 0.001). No tumor characteristics or patient demographics influenced diagnostic agreement at any site in the colon. CONCLUSIONS: Given the potential to yield valuable information while limiting patient discomfort, US should be reconsidered as a means of assessing colon cancer.
PURPOSE: Although noninvasive and highly informative, transabdominal ultrasonography (US) is not yet an accepted means of staging colorectal cancer preoperatively. This prospective study evaluated the diagnostic accuracy of US in preoperative staging of patients with resectable colon cancers. METHODS: A total of 98 patients with primary colon cancer diagnosed by colonoscopy at our institute between January, 2011 and June, 2014 underwent preoperative ultrasonographic tumor staging. Depth of tumor infiltration (T-stage) was assessed by standard means (i.e., extent of mural involvement), analyzing agreement in US and histopathology determinations. RESULTS: All but two colon cancers (at splenic flexure) were detected by US (98%, 96/98). Compared with histopathology, overall accuracy of US in determining T-stage was 64% (61/96), indicating moderate reproducibility (κ coefficient 0.48; 95% CI 0.35-0.62; p < 0.001). Using a three-tier approach of graded muscularis propria (MP) involvement (Tis/T1, below MP; T2, within MP; and T3/T4, beyond MP), diagnostic agreement increased to 89% (85/96), with good agreement (κ coefficient 0.77; 95% CI 0.64-0.90; p < 0.001). No tumor characteristics or patient demographics influenced diagnostic agreement at any site in the colon. CONCLUSIONS: Given the potential to yield valuable information while limiting patient discomfort, US should be reconsidered as a means of assessing colon cancer.