The accuracy of transrectal ultrasound in predicting the pathological stage of low-lying rectal cancer after preoperative chemoradiation therapy

Purpose: There has been a growing interest in the use of preoperative radiation therapy in rectal cancer treatment in the last years. The need for accurate preoperative staging is important so as to avoid overtreatment in stage I patients, and to select patients who require downstaging prior to surgery as they are technically inoperable. While transrectal ultrasound (TRUS) has been reported to accurately stage preoperative patients, its efficacy postradiation has been questioned, The authors report a series studied by TRUS to contribute to the discussion on the role of this method. Methods and Materials: Twenty-eight patients with rectal cancer were accrued. Twenty-six patients, clinically staged T2-T4 or/and N1-N3 between March 1990 to October 1993, underwent preoperative chemoradiation, Two patients (T2N0) were treated by local excision and postoperative radiotherapy. Following therapy and just before surgery, each patient was restaged by TRUS. These results were subsequently compared with a pathological stage of resected specimen for both the primary tumor (T) and regional lymph nodes (LN), Results: The accuracy of TRUS for T stage after chemoradiation was 92.8% (positive predictive value [PPV] 94.4%, negative predictive value [NPV] 90.0%). The accuracy for LN staging after chemoradiation was 60.7% (PPV 100.0%, NPV 54.0%), because LN located outside the scanning range were missed, Conclusion: Based on our results, we conclude that TRUS of the primary tumor is an accurate staging technique for patients with rectal cancer treated with preoperative chemoradiation, (C) 1999 Elsevier Science Inc.