Impact of computed tomography vs. intrarectal ultrasound on the diagnosis, resectability, and prognosis of locally recurrent rectal cancer

The use of modern techniques of imaging in the postoperative follow-up is reported to allow an earlier diagnosis of local recurrence in patients operated on with anterior resection for rectal cancer and, consequently, to allow a higher percentage of local recurrence resection to be performed. Although intrarectal ultrasound (IU) has proved highly reliable in preoperative staging, its value in relapse detection has been investigated only in retrospective studies and rarely compared with that of computed tomography (CT). The present prospective study aims at evaluating the role of IU vs. CT in the diagnosis of local recurrence and at verifying whether an earlier diagnosis and a higher resectability rate of recurrence result in an acceptable long-term survival. Thirty-seven patients who had undergone low and ultralow anterior resection for rectal cancer (anastomosis within 10 cm of the anal verge) were investigated prospectively. All the patients have been followed up by IU and CT at predetermined intervals. Six local recurrences were detected. CT correctly identified all the local recurrences (sensitivity = 100 percent, specificity = 93 percent, and accuracy = 94.5 percent); IU correctly identified only four of six local recurrences (sensitivity = 66.6 percent, specificity = 93 percent, and accuracy = 89 percent). Four patients with local recurrence underwent surgical treatment (resectability rate = 66.6 percent). Abdominoperineal resection in three patients and Hartmann's procedure in one patient were performed. In the other two patients, extensive metastatic liver involvements contraindicated surgery. All the resected patients were alive after one year; two of them are disease free, and the other two experienced recurrent disease. In conclusion, CT seems to have a higher sensitivity and accuracy in relapse detection. The increase in the local recurrence resectability rate does not result in a significant improvement in longterm survival. However, the good quality of life justifies the high cost of an intensive follow-up and a more aggressive surgical approach. © 1993 American Society of Colon and Rectal Surgeons.