RESUMO
BACKGROUND: EUS is an established method for staging of rectal cancer. Nevertheless, there are few data about the significance of infiltration depth measured by EUS. OBJECTIVE: Assessment of accuracy of T and N staging by EUS with attention to infiltration depth as provided by EUS. DESIGN: Part retrospective, part prospective study. SETTING: Community and tertiary referral hospital, covering the period before neoadjuvant therapy for advanced rectal cancer was established. PATIENTS: Eighty-three patients (60% men) with untreated rectal cancer. INTERVENTION: EUS examination. MAIN OUTCOME MEASUREMENTS: We examined the correlation between EUS findings and postoperative histology. T3 cancers as diagnosed by EUS were classified into minimally invasive (1-2 mm) or advanced (>2 mm) tumors depending on the depth of infiltration beyond the muscularis propria. RESULTS: Accuracy of T staging and N status was 76% and 63%, respectively. Overstaging by EUS was more common in minimally invasive T3 by EUS (uT3) (8 of 16 [50%]) compared with advanced uT3 tumors (1 of 24 [4%]) (P=.01). Accuracy of EUS discrimination between T1/2 and T3/4 in rectal cancer for all but minimally invasive uT3 rectal tumors was 88%. LIMITATIONS: Partly retrospective analysis. CONCLUSIONS: EUS examination of rectal carcinoma determines T stage with high accuracy. Additionally, it provides information beyond T and N staging. The 50% probability of overstaging patients with minimally invasive uT3N0 by EUS may argue for managing these cancers as stage I disease, ie, to refer the patient for surgery without neoadjuvant therapy.