INTERET DE L'ECHOGRAPHIE ENDORECTALE POUR LE TRAITEMENT DES TUMEURS RECTALES

Objectives: To determine the diagnostic accuracy of endosonography and to appreciate its influence on the therapeutic strategy. Methods: Sixty-two patients referred to the gastroenterology unit between April 1990 and February 1995 for a rectal tumor. Thirty-two patients did not receive any preoperative treatment (group A) and 30 were treated by radiotherapy or chemoradiotherapy before surgery (group B). Transrectal ultrasonography was performed with a Bruel and Kjaer device. Resuls: Diagnostic accuracy for parietal infiltration was 84% for the entire series, 94% for group A and 73% for group B. Diagnostic accuracy of lymph node invasion was 71% for the entire series, 81% and 60% for groups A and B, respectively. It is highly probable that a histopathologic down-staging due to preoperative treatment explained the results in the group B. Using a pragmatic approach which combined the results for parietal infiltration and for lymph node invasion, transrectal ultrasonography would have correctly selected 20 among the 25 patients who could have been treated by local excision. The use of this same pragmatic approach in patients with high risk of local recurrence enabled correct selection of 26 among the 32 exposed patients. Conclusion: We conclude that transrectal ultrasonography: 1°) is a reliable technique for the pretherapeutic staging of rectal cancer, especially for the assessment of parietal infiltration. Progress is needed for the diagnosis of lymph node invasion; 2°) selects well the patients who can be treated by local excision; 3°) is a reliable technique for the selection of patients who need preoperative treatment.