The role of endorectal ultrasound and magnetic resonance imaging in the management of early rectal lesions in a tertiary center.

BACKGROUND

In early rectal cancer, ERUS has a vital role in determining radical or local excision based on identification of T-stage. Transanal endoscopic microsurgery (TEMs) has a reduced morbidity and mortality compared with radical surgery. Correct identification of lesions that can be managed with TEMs is therefore imperative. Our aim was to assess the accuracy of ERUS in identifying mucosal/submucosal lesions and thus their suitability for TEMs.

PATIENTS AND METHODS

A retrospective analysis of a prospectively maintained database of patients who underwent ERUS was carried out over an initial 25-month period at a tertiary colorectal center. Our main outcome measures were T-stage measured using ERUS or magnetic resonance imaging (MRI) (indicating suitability for local excision, ie, ≤ T1) with correlation with that of the subsequent surgical specimen and improvement in accuracy over time. After data analysis and review, the study was repeated over the subsequent 12 months to establish whether there was a learning curve with the use of ERUS.

RESULTS

Over the initial period, 52 patients who met the inclusion criteria underwent ERUS. T-staging was accurate in 73.1% (38/52) with identification of ≤ T1 lesions having a sensitivity of 70.8% and a specificity 100%. The accuracy, sensitivity, and specificity of MRI was similar to that of ERUS (72.7%, 70.0%, and 100% respectively). Over the subsequent period, 23 patients underwent ERUS with T-staging accuracy improving to 78.3% (18/23) (P = .777).

CONCLUSION

In our experience, ERUS is a useful adjunct to clinical assessment and pelvic MRI in determining suitability for local excision. Its 100% specificity in determining that a lesion is limited to the mucosa or submucosa aids in the assessment of lesions that are being considered for submucosal resection. Over the time periods assessed, improvement in T-staging accuracy was demonstrated, which might be due to the presence of a learning curve.