Endorectal ultrasound does not reliably identify patients with uT3 rectal cancer who can avoid neoadjuvant...

Neoadjuvant chemoradiation (NCRT) may be avoided in some patients with T3-staged rectal cancer undergoing radical resection. We aimed to evaluate the accuracy of endorectal ultrasound (ERUS) in the nodal staging of uT3 tumors and hence the decision for administration of NCRT.

Patients with uT3-staged rectal cancer who underwent proctectomy were retrospectively identified. The accuracy of ERUS for detecting nodal involvement was determined for patients who did not undergo NCRT. In order to evaluate the impact of use of NCRT, oncologic outcomes, functional outcomes, and quality of life (QOL) were compared for patients who received NCRT (group A) and those who did not (group B).

For 384 patients who were included, ERUS overstaging rate for nodal involvement was 6.3% while understaging rate was 23.2%. For the 289 patients in group A and 95 in group B, Kaplan-Meier analysis showed similar 5-year local recurrence rates (3.5%), overall survival (76.9 vs 75.6%), and disease-free survival (87.9 vs 88.1%). Node positivity on final pathology was however associated with worse 5-year local recurrence (9.3 vs 4.3%). For patients undergoing restorative resection, NCRT was associated with worse functional outcomes but QOL was similar.

ERUS identification of nodal involvement used as a criterion for NCRT carries a greater risk for undertreatment than overtreatment. Undertreatment adversely affects oncologic outcomes. While there is functional impairment related to NCRT, its effect on QOL is non-significant. The decision for omitting neoadjuvant chemoradiation for uT3 rectal cancer should hence not be based on ERUS nodal staging alone.