Colorectal Cancer
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 7, 2005; 11(21): 3245-3249
Published online Jun 7, 2005. doi: 10.3748/wjg.v11.i21.3245
Increased proliferation activity measured by immunoreactive Ki67 is associated with survival improvement in rectal/recto sigmoid cancer
Eeva Salminen, Salla Palmu, Tero Vahlberg, Peter J. Roberts, Karl-Owe Söderström
Eeva Salminen, Salla Palmu, Department of Oncology and Radiotherapy, Turku University Hospital, 20510 Turku, Finland
Tero Vahlberg, Department of Biostatistics, University of Turku, 20510 Turku, Finland
Peter J. Roberts, Department of Surgery, Turku University Hospital, 20510 Turku, Finland
Karl-Owe Söderström, Department of Pathology, Turku University Hospital, 20510 Turku, Finland
Author contributions: All authors contributed equally to the work.
Supported by the Emil Aaltonen Foundation and Turku University Research Foundation
Correspondence to: Dr. Eeva Salminen, Department of Oncology and Radiotherapy, POB 52, Fin-20510 Turku, Finland. eevsal@utu.fi
Fax: +358-2-3332809
Received: August 13, 2004
Revised: August 14, 2004
Accepted: September 30, 2004
Published online: June 7, 2005
Abstract

AIM: To assess the expression of Ki67 as prognosticator in rectal/recto sigmoid cancer.

METHODS: Samples from 146 patients with rectal and recto sigmoid cancer were studied for expression of Ki67 and its prognostic significance in comparison with clinico-pathological predictors of survival. Formalin-fixed, paraffin-embedded tissues from 6 (4.1%) patients with T1, 26 (17.8%) with T2, 94 (64.4%) with T3, and 20 (13.7%) with T4 tumors were studied. Ki67 expression was determined immunohistochemically. Samples were divided according to mean value into high (>40%) and low (≤40%) expression. Areas of extensive proliferation (>50%) were defined as ‘hot spot’ areas.

RESULTS: Hot spot areas were present in samples regardless of histopathological grade. Lower TNM and Dukes stage and higher expression of Ki67 and presence of Ki67 hot spot areas in histopathological samples were associated with better survival, whereas no association was observed with histopathological grade (P = 0.78). In Cox multivariate regression analysis, significant prognostic factors were Dukes stage (P<0.001), presence of lymph node metastases (P = 0.015), age (P = 0.035) and presence of Ki67 hot spot areas (P = 0.044).

CONCLUSION: Proliferative activity as measured by Ki67 in rectal cancer is associated with survival improvement compared with patients with low Ki67. Areas of prognostically significant increased proliferation were found independently of histopathological tumor grade.

Keywords: Rectal cancer; Stage; Grade; Proliferative activity; Ki67