Relationship between chromosome 18q status and colorectal cancer prognosis: a prospective, blinded analysis of 280 patients.
BACKGROUND
The relationship between chromosome 18q allelic imbalance (AI) and survival in colorectal cancer (CRC) is unclear, and study design may have contributed to inconsistent results previously reported.


METHODS
Two hundred and eighty tumours from CRC patients participating in a molecular sub-study from a single multicentre trial of adjuvant intra-portal 5-fluorouracil were genotyped at 5 chromosome 18q microsatellite markers, blinded to clinical data and prospective to follow-up. The relationship between overall survival and AI was examined.


RESULTS
Two hundred and fifty-five tumours were informative for AI. The overall rate of AI was 49%. AI was not associated with age, tumour site or size. There was no difference in five-year survival rate between patients with (60.0% SE 5.2%) and without AI (61.4% SE 5.0%), even after correcting for covariates (HR=1.17, 95%CI:0.79-1.74, p=0.4).


CONCLUSIONS
Our data does not [corrected] support chromosome 18q AI as an important marker of survival in the adjuvant setting. It should not, therefore, be used outside clinical trials.
Popat
Sanjay
S
Section of Cancer Genetics, Institute of Cancer Research, Sutton, UK. sanjay.popat@icr.ac.uk
Zhao
Dongbing
D
Chen
Zhengming
Z
Pan
Hongchao
H
Shao
Yongfu
Y
Chandler
Ian
I
Houlston
Richard S
RS
D000293:Adolescent; D000328:Adult; D000368:Aged; D022981:Allelic Imbalance; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D004311:Double-Blind Method; D005260:Female; D005838:Genotype; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies