Preoperative biopsy of pararectal lymph nodes in rectal cancer using endoluminal ultrasonography

Abstract
Because definitive information regarding lymph node status in rectal cancer would be valuable preoperatively, we evaluated the safety, feasibility, and accuracy of performing endoluminal ultrasound-guided biopsies of pararectal lymph nodes in 26 rectal cancer patients. Biopsies were compared with the pararectal tissues removed at surgery. Using a longitudinally oriented 7.0-MHz ultrasound probe and an 18-gauge spring-loaded core biopsy needle, patients underwent biopsies of lymph nodes detected ultrasonographically without complications. A biopsy of adenocarcinoma was obtained in 13 patients, lymphoid material in 5 patients, and irrelevant material in 8 patients. Accuracy rate (true positives divided by number of procedures) was 77 percent, with a sensitivity of 71 percent, a specificity of 89 percent, a positive predictive value of 92 percent, and a negative predictive value of 62 percent. When adenocarcinoma or lymphoid material was obtained, there was only one false positive and one false negative. Endoluminal ultrasonographyguided lymph node biopsy is simple and safe, and when adenocarcinoma or lymphoid material is obtained on biopsy, clinical decision making can be based on this information.