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World J Gastroenterol. Jun 14, 2014; 20(22): 6809-6814
Published online Jun 14, 2014. doi: 10.3748/wjg.v20.i22.6809
Prognostic and predictive significance of MSI in stages II/III colon cancer
Zacharenia Saridaki, John Souglakos, Vassilis Georgoulias
Zacharenia Saridaki, John Souglakos, Vassilis Georgoulias, Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, 71110 Heraklion, Crete, Greece
Zacharenia Saridaki, John Souglakos, Vassilis Georgoulias, Department of Medical Oncology, University General Hospital of Heraklion, 71110 Heraklion, Crete, Greece
Author contributions: Saridaki Z and Souglakos J designed the review and wrote the manuscript; Georgoulias V was involved in editing the manuscript.
Correspondence to: John Souglakos, MD, PhD, Department of Medical Oncology, University General Hospital of Heraklion, Voutes, PO BOX 1352, 71110 Heraklion, Crete, Greece. georgsec@med.uoc.gr
Telephone: +30-2810-392783 Fax: +30-2810-392857
Received: October 13, 2013
Revised: December 29, 2013
Accepted: March 4, 2014
Published online: June 14, 2014
Processing time: 246 Days and 15.6 Hours
Abstract

In colon cancer, classic disease staging remains the key prognosis and treatment determinant. Although adjuvant chemotherapy has an established role in stage III colon cancer patients, in stage II it is still a subject of controversy due to its restriction to a small subgroup of patients with high-risk histopathologic features. Patients with stage II tumors form a highly heterogeneous group, with five-year relative overall survival rates ranging from 87.5% (IIA) to 58.4% (IIC). Identifying those for whom adjuvant chemotherapy would be appropriate and necessary has been challenging, and prognostic markers which could serve in the selection of patients more likely to recur or benefit from adjuvant chemotherapy are eagerly needed. The stronger candidate in this category seems to be microsatellite instability (MSI). The recently reported European Society for Medical Oncology guidelines suggest that MSI should be evaluated in stage II colorectal cancer patients in order to contribute in treatment decision-making regarding chemotherapy administration. The hypothetical predictive role of MSI regarding its response to 5-fluorouracil-based adjuvant chemotherapy has proven a much more difficult issue to address. Almost every possible relation between MSI and chemotherapy outcome has been described in the adjuvant colon cancer setting in the international literature, and the matter is far from being settled. In this current report we critically evaluate the prognostic and predictive impact of MSI status in patients with stage II and stage III colon cancer patients.

Keywords: Microsatellite instability; Stage II; Stage III; Colon cancer; Predictive; Prognostic

Core tip: Adjuvant chemotherapy in patients with stage II colon cancer is still a subject of controversy. Stage II tumors are highly heterogeneous, with five-year relative overall survival rates ranging from 58.4% to 87.5%. Recently reported European Society for Medical Oncology guidelines suggest that microsatellite instability (MSI) should be evaluated in stage II colorectal cancer patients in order to contribute in treatment decision-making regarding chemotherapy administration. The current report critically evaluates the prognostic and predictive impact of MSI status in patients with stage II and stage III colon cancer.