Is a proliferation index of cancer cells a reliable prognostic factor after hepatectomy in patients with colorectal liver metastases?

Background: In spite of many reports focusing on prognostic factors after h epatectomy in patients with colorectal liver metastases, few studies have i nvestigated pathological factors, eg, fibrous pseudocapsulation, growth pat tern at the tumor margin, and proliferation activity of cancer cells, other than histological type and surgical margin. The aim of the present study w as to investigate whether absence of pseudocapsulation, infiltrative growth pattern of metastases, and higher proliferation of cancer cells shown by K i-67 immunohistochemical reactivity were associated with poorer survival af ter hepatectomy among patients with colorectal liver metastases. Methods: Between 1988 and 1998, 221 patients underwent hepatic resection of colorectal metastases with curative intent in our institution. Pathology a nalyses were focused on pseudocapsulation of liver metastases, growth patte rn at the tumor edge, and Ki-67 labelling index (Ki-67 LI) of cancer cell n uclei. Univariate analyses of survival and of disease-free survival were pe rformed for several clinicopathological factors, and multivariate analyses of survival and disease-free survival were also performed. Results: The univariate survival analyses showed that pseudocapsulation, gr owth pattern, and Ki-67 LI were significant prognostic factors, besides syn chronous versus metachronous occurrence of metastases, carcinoembryonic ant igen level before hepatectomy, and number of metastases. A multivariate ana lysis showed that Ki-67 labeling index was the most reliable prognostic fac tor of survival. In addition, Ki-67 LI and microscopic growth pattern were multivariately predictive factors of disease-free survival. Conclusions: This large single-institution study showed that investigation of cancer cell proliferation and pathologic characteristics of the tumor ma rgin are major prognostic factors. (C) 2001 Excerpta Medica, Inc. All right s reserved.