EVALUATION AND BIOPSY OF RECURRENT RECTAL-CANCER USING 3-DIMENSIONAL ENDOSONOGRAPHY

PURPOSE: The value of endorectal ultrasonography for postoperative fol low-up of rectal cancer is limited by the inability to distinguish rec urrent malignancy from benign lesions, e.g., fibrotic tissue. This stu dy was conducted to investigate the role of three-dimensional (3D) end osonography for evaluation and biopsy of recurrent rectal cancer. METH ODS: Endorectal ultrasonography was performed in routine follow-up pro gram after resection of rectal cancer. 3D volume scans were recorded u sing a bifocal multiplane 3D transducer (7.5/10 MHz) with a 100 degree s longitudinal and a 360 degrees transversal scan angle. For transrect al ultrasound-guided biopsy of pararectal lesions, a specially designe d targeting device was attached to the endoprobe. RESULTS: Overall par arectal lesions were detected in 28 of 163 patients (17 percent) who w ere undergoing endorectal ultrasonography for follow-up after resectio n of rectal cancer. 3D image analysis facilitated assessment of suspic ious pararectal lesions by contemporary display of three perpendicular scan planes or volume reconstructions of the scanned area. Ultrasound -guided biopsy was performed in all 28 patients with pararectal lesion s identified by endorectal ultrasonography. Biopsy revealed recurrent disease or lymph node metastases in seven and two patients, respective ly. Benign lesions explained the endosonographic findings in 17 patien ts. All patients with benign histology still have no evidence of recur rent disease after a median follow-up of seven months. Nonrepresentati ve material was obtained in only 2 of 28 patients (accuracy, 93 percen t). Histology changed the endosonographic diagnosis in 28 percent of c ases. CONCLUSIONS: 3D endosonography with ultrasound-guided biopsy imp roves the diagnosis of extramural recurrence after curative resection of rectal cancer. 3D image display allows precise control of the posit ion of the biopsy needle within the target.