ENDOSCOPICALLY REMOVED MALIGNANT COLORECTAL POLYPS - CLINICOPATHOLOGICAL CORRELATIONS

Background/Aims: Treatment options for patients with endoscopically re moved malignant colorectal polyps are polypectomy alone vs, polypectom y followed by surgery. The aim of this study was to define histopathol ogic parameters that can be used for clinically relevant treatment dec isions. Methods: Five pathologists evaluated 140 polyps for the presen ce or absence of unfavorable histology. Unfavorable histology was tumo r at or near (less than or equal to 1.0 mm) the margin and/or grade II I and/or lymphatic and/or venous invasion. Adverse outcome was recurre nt and/or focal cancer and/or lymph node metastasis. Results: Adverse outcome was 19.7% (14 of 71), 8.6% (2 of 23), and 0% (0 of 46) when un favorable histology was present, indefinite (lack of agreement), and a bsent, respectively (P < 0.0005, present vs. absent). Four patients wi th cancer >1.0 mm from the margin had an adverse outcome (2 with lymph atic invasion and 2 indefinite for lymphatic invasion). Four patients with negative resections later developed distant metastases. Eight pat ients (6.3%) died of disease, and 2 of 69 without unfavorable histolog y (both indefinite for lymphatic invasion) had an adverse outcome. Int erobserver strength of agreement was substantial to almost perfect for margin, grade, and venous invasion and fair to substantial for lympha tic invasion, Conclusions: This system is usable clinically. Patients with unfavorable histology are probably best managed by resection post polypectomy, whereas in the absence of unfavorable histology, they pro bably can be treated by polypectomy only.