CHARACTERISTICS OF RECTAL CARCINOMAS THAT PREDICT THE PRESENCE OF LYMPH-NODE METASTASES - IMPLICATIONS FOR PATIENT SELECTION FOR LOCAL THERAPY

Background and Objectives: It has been estimated that approximately 5% of middle and low rectal adenocarcinomas are amenable to local therap y. However, these treatment modalities are limited by their failure to identify and treat regional nodal metastases. Methods: This study was undertaken to evaluate the role of tumor size, depth of penetration i nto the rectal wall, degree of histologic differentiation, DNA ploidy status, and their combination on the presence or absence of metastases in perirectal lymph nodes. Logistic regression was used to quantitati vely predict the probability of positive lymph nodes. Results: Tumor s ize did not correlate with the presence of nodal involvement; however, worsening degree of differentiation, increasing depth of wall penetra tion and aneuploidy did statistically correlate with the presence of n odal metastases. For any combination of tumor traits, aneuploidy marke dly increased the probability of positive lymph nodes over that observ ed with diploid tumors. Conclusions: The combination of degree of diff erentiation, depth of penetration, and ploidy status may be used to id entify patients whose tumors may be adequately treated with local meas ures. For any combination of tumor traits, aneuploidy markedly increas ed the probability of positive lymph nodes over that observed with dip loid tumors. (C) 1998 Wiley-Liss, Inc.