In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 27, No. 15_suppl ( 2009-05-20), p. 4001-4001
Abstract:
4001 Background: Patients with high MSI (MSI H) tumors are increasingly being recognized as a prognostic and predictive subgroup in colon cancer (COC). We investigated the incidence of MSI-H in stage II (n=395) and stage III (n=859) COC, its association with histopathological variables and its prognostic and predictive impact. Methods: The study accrued 3278 patients with Stage II and Stage III COC to receive post-operative 5-FU -LV with or without irinotecan (IRI). Paraffin tissue blocks of 1327/1405 available patients were successfully analyzed for MSI status using the NCI extended panel of 10 markers. MSI-H was defined as instability in ≥3 markers. Relapse Free Survival (RFS) and Overall Survival (OS, median follow up 68 months) were assessed. Results: MSI H was present in 22% (85) of Stage II and 12% (103)of Stage III colon cancer . MSI H status was significantly associated with age 〈 60, higher T stage, higher grade, lower N stage and right sided tumor location. The table presents univariate RFS and OS hazard rates (with 95% confidence intervals) for prognostic and predictive impact per stage and arm, estimated by a survival regression analysis using Cox proportional hazards model and of selected P values by Wald tests. Conclusions: Microsatellite instability is a strong prognostic factor for RFS and OS when considering Stage II and Stage III COC. Subgroup analysis suggests a stronger effect in Stage II than in Stage III, but is limited by sample size and multiple testing. Taken together with differences in incidence between the stages, this may suggest stage specific biological effects of MSI. In contrast to previous reports (a) in Stage II the prognostic effect of MSI remained significant even in pts treated with 5FU (w/o IRI),(b) There is no evidence for an effect of the addition of IRI. [Table: see text] [Table: see text]
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2009.27.15_suppl.4001
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2009
detail.hit.zdb_id:
2005181-5
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