Use of preoperative ultrasound staging for treatment of rectal cancer

INTRODUCTION: Transrectal ultrasound is the standard method for preoperativ e staging of rectal cancer. This study reviews the accuracy of transrectal ultrasound staging for T3 disease and its use in the selection of patients for neoadjuvant chemoradiation. METHODS: One hundred seventeen patients und erwent preoperative transrectal ultrasound evaluation for rectal cancer. Ac curacy of transrectal ultrasound was evaluated among 70 patients not receiv ing preoperative chemoradiation. Forty-seven patients received neoadjuvant chemoradiation based on transrectal ultrasound results. Tumor downstaging a nd early recurrence were evaluated among 45 of 47 patients receiving neoadj uvant chemoradiation. RESULTS: Among 70 nonirradiated patients, 19 were pat hologic Stage pT3. Transrectal ultrasound correctly identified 18 of 19 pat ients with Stage pT3 (sensitivity, 94.7 percent). Transrectal ultrasound co rrectly identified 44 of 51 patients with less than pT3 disease (specificit y, 86.3 percent). After preoperative chemoradiation in 45 patients with ult rasound Stage uT3 or uT4 tumors, 56 percent of them experienced a reduction in T stage. Residual nodal disease was found in 31 percent of patients. A complete pathologic response with no residual disease at operation was obse rved in 22 percent of patients. During a median follow-up period of 21 mont hs after diagnosis, seven patients experienced a recurrence of their diseas e at a median of 12 months after diagnosis. Five of seven patients with rec urrence were among a subgroup of ten patients who both failed to downstage T and had residual nodal disease at operation. CONCLUSION: Transrectal ultr asound is an accurate modality for selecting patients for neoadjuvant treat ment. Preoperative chemoradiation produced downstaging in 56 percent of pat ients. Factors related to early recurrence included residual nodal disease and failure to downstage T after neoadjuvant chemoradiation.