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Ann Oncol. 2017 May 1;28(5):1023-1031. doi: 10.1093/annonc/mdx052.

Prediction of overall survival in stage II and III colon cancer beyond TNM system: a retrospective, pooled biomarker study.

Author information

1
Computational Oncology, Sage Bionetworks, Seattle, USA.
2
Oncology Data Science Group, Vall d´Hebron Institute of Oncology and Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain.
3
Division of Medical Oncology, Mayo Clinic and Mayo Comprehensive Cancer Center, Rochester.
4
Epidemiology Department, University of Washington and Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, USA.
5
Molecular Digestive Oncology Unit, University Hospital Gasthuisberg, Leuven, Belgium.
6
Department of Gastrointestinal Surgery, Institute of Clinical Medicine, and K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway.
7
Department of Molecular Oncology, Institute for Cancer Research, and K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway.
8
Colorectal Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, VIC, 3010, Australia.
9
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia.
10
Genetic Medicine and Familial Cancer Centre, The Royal Melbourne Hospital, Parkville, Australia.
11
Envoi Specialist Pathologists, Herston, Queensland, Australia.
12
School of Medicine, University of Queensland, Herston, Australia.
13
Diagnostics Evaluation Branch, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institute of Health, Rockville, USA.
14
SIB Swiss Institute Bioinformatics, Lausanne, Switzerland.
15
Department of Oncology, Ludwig Center for Cancer Research, University Lausanne, Lausanne, Switzerland.
16
Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, USA.

Abstract

Background:

TNM staging alone does not accurately predict outcome in colon cancer (CC) patients who may be eligible for adjuvant chemotherapy. It is unknown to what extent the molecular markers microsatellite instability (MSI) and mutations in BRAF or KRAS improve prognostic estimation in multivariable models that include detailed clinicopathological annotation.

Patients and methods:

After imputation of missing at random data, a subset of patients accrued in phase 3 trials with adjuvant chemotherapy (n = 3016)-N0147 (NCT00079274) and PETACC3 (NCT00026273)-was aggregated to construct multivariable Cox models for 5-year overall survival that were subsequently validated internally in the remaining clinical trial samples (n = 1499), and also externally in different population cohorts of chemotherapy-treated (n = 949) or -untreated (n = 1080) CC patients, and an additional series without treatment annotation (n = 782).

Results:

TNM staging, MSI and BRAFV600E mutation status remained independent prognostic factors in multivariable models across clinical trials cohorts and observational studies. Concordance indices increased from 0.61-0.68 in the TNM alone model to 0.63-0.71 in models with added molecular markers, 0.65-0.73 with clinicopathological features and 0.66-0.74 with all covariates. In validation cohorts with complete annotation, the integrated time-dependent AUC rose from 0.64 for the TNM alone model to 0.67 for models that included clinicopathological features, with or without molecular markers. In patient cohorts that received adjuvant chemotherapy, the relative proportion of variance explained (R2) by TNM, clinicopathological features and molecular markers was on an average 65%, 25% and 10%, respectively.

Conclusions:

Incorporation of MSI, BRAFV600E and KRAS mutation status to overall survival models with TNM staging improves the ability to precisely prognosticate in stage II and III CC patients, but only modestly increases prediction accuracy in multivariable models that include clinicopathological features, particularly in chemotherapy-treated patients.

KEYWORDS:

BRAF mutation; KRAS mutation; colon cancer; microsatellite instability; prognosis

PMID:
28453697
PMCID:
PMC5406760
DOI:
10.1093/annonc/mdx052
[Indexed for MEDLINE]
Free PMC Article

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