The role of transrectal ultrasound-guided biopsy in the postoperative follow-up of patients with rectal cancer

Background. The value of endorectal ultrasound (EUS) in the diagnosis of recurrent rectal cancer is limited by the inability to differentiate between malignant and benign lesions. We have prospectively investigated the role of EUS with transrectal ultrasound-guided biopsy in the postoperative follow-up of rectal cancer. Methods. Since 1995, patients who had undergone a sphincter-saving operation for rectal cancer (n = 312) were followed-up by a standard program including rectal palpation, carcinoembryonic antigen monitoring, computed tomography, and EUS. Transrectal EUS-guided biopsy of perirectal lesions was performed in 68 patients with perirectal lesions by using a rigid endoprobe with a 10 MHZ multiplane transducer and special targeting device. Results. Overall local recurrence was observed in 36 patient. Intraluminal recurrence was diagnosed by proctoscopy in 12 patients. Transrectal EUS-guided biopsy showed pelvic recurrence in 22 of 68 patients with perirectal lesions. Biopsy specimens with benign histology were obtained form 41 patients, and the procedure failed in 5 cases (accuracy, 92%). There was a strong agreement between transrectal biopsy results and the final diagnosis (kappa =0.84), the sensitivity and specificity being 91% and 93%, respectively. In contrast, clinical examination (kappa =0.27), computed tomography (kappa =0.47), or EUS (kappa =0.42) showed only a moderate level of agreement with th histopathologic diagnosis, mainly because of the limited specificity of all 3 methods (65% vs 46% vs 57%). EUS-guided biopsy was significantly more accurate than computed tomography and EUS (P<.01). The biopsy results had a considerable impact on the management in 18 of 68 patients (26%). Conclusions. Transrectal EUS-guided biopsy is a safe and efficient method for tissue sampling of perirectal lesions. This minimally invasive and inexpensive technique improves the accuracy of endorectal ultrasound in the diagnosis of recurrent rectal cancer.