Diagnostic value, safety, and histopathologic discrepancy risk factors for endoscopic forceps biopsy and transrectal ultrasound-guided core needle biopsy in rectum lesions.

ABSTRACT

BACKGROUND: Accurate preoperative pathologic diagnosis is very important for making appropriate therapeutic decisions for patients with rectal lesions. This study aimed (I) to determine diagnostic value and safety of endoscopic forceps biopsy (EFB) and transrectal ultrasound (TRUS)-guided core needle biopsy (CNB), and (II) to analyze the risk factors for their histopathologic discrepancies, with a particular focus in identifying the indicators for re-biopsy using TRUS-guided CNB after EFB. METHODS: We retrospectively reviewed the records of 102 patients who received EFB and TRUS-guided CNB before surgery. The histopathologic concordance and risk factors for underdiagnosis by EFB and TRUS-guided CNB were analyzed. RESULTS: Compared with postoperative pathology, the histopathologic discrepancy rate of EFB and TRUS-guided CNB was 51.0% (52/102 lesions) and 8.8% (9/102 lesions), respectively. The kappa value for consistency with postoperative pathology findings was 0.420 for EFB and 0.876 for TRUS-guided CNB. The multivariate analyses and receiver operating characteristic (ROC) curve indicated that lesions thickness ≥13.5 mm [OR 1.080 (95% CI 1.021-1.142), P=0.007] and flat/depressed shape [OR 0.206 (95% CI 0.076-0.564), P=0.002] were significantly associated with histopathologic discrepancies in EFB. CONCLUSIONS: EFB was of limited clinical value in identifying the preoperative diagnosis of rectal lesions. Lesions thickness and flat/depressed shape at EFB were independent risk factors for pathologic discrepancies. TRUS-guided CNB may serve as a safe and effective supplement to routine EFB.