Intramucosal carcinoma on biopsy reliably predicts invasive colorectal cancer.

Abstract

The diagnosis of invasive malignancy on biopsies from colorectal neoplasms can be challenging. The concept of intramucosal carcinoma as an indicator of invasive malignancy is somewhat controversial within histopathology circles despite current World Health Organization (WHO) definitions. This study was designed to correlate the biopsy finding of intramucosal carcinoma with the pathology findings after formal surgical excision. We evaluated 89 patients whose initial forceps biopsy contained only intramucosal carcinoma. All tumors were subsequently resected and subjected to formal pathology assessment. Of 89 patients, 97% were shown to have frankly invasive adenocarcinoma by the current WHO definition. The positive predictive value of intramucosal carcinoma at biopsy for invasive cancer was 96.6% This study indicated that there should be a greater willingness among colorectal pathologists to accept the biopsy finding of intramucosal carcinoma as the earlier form of invasive malignancy. Clinicians should alter their treatment algorithms accordingly.