Familial colorectal cancer risk by subsite of primary cancer: a population-based study in Utah

TitleFamilial colorectal cancer risk by subsite of primary cancer: a population-based study in Utah
Publication TypeJournal Article
Year of Publication2015
AuthorsSamadder N.J, Smith K.R, Mineau G.P, Pimentel R., Wong J., Boucher K., Pappas L., Singh H., Ahnen D., Burt R.W, Curtin K.
JournalAlimentary Pharmacology & Therapeutics
Date PublishedMar
ISBN Number0269-2813
Accession NumberWOS:000349617000006
Keywordsagreement, colon-cancer, database, hazards regression-model, HISTORY, metaanalysis, STATISTICS

BackgroundFamilial occurrence is common in colorectal cancer (CRC), but whether this increased familial risk differs by colonic subsite of the index patients CRC is not well understood.
AimTo quantify the risk of CRC in first-degree (FDR), second-degree (SDR) and first cousin (FC) relatives of individuals with CRC, stratified by subsite in the colorectum and age at diagnosis.
MethodsColorectal cancers diagnosed between 1980 and 2010 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age and gender-matched CRC-free controls were selected to form the comparison group for determining CRC risk in relatives using Cox regression analysis.
ResultsOf the 18208 index patients diagnosed with CRC, 6584 (36.2%) were located in the proximal colon, 5986 (32.9%) in the distal colon and 5638 (31%) in the rectum. The elevated risk of CRC in relatives was similar in analysis stratified for CRC colorectal subsites in the index cases. FDR had similarly elevated risk of all site CRC, whether the index patient had cancer in the proximal colon [hazards ratio (HR): 1.85; 95% CI: 1.70-2.02], distal colon (HR: 1.90; 95% CI: 1.73-2.08) or rectum (HR: 1.83; 95% CI: 1.66-2.02) compared to relatives of controls. This risk was consistently greater for FDR when cases developed CRC below the age of 60years.
ConclusionsRelatives of CRC patients have a similarly elevated risk of CRC regardless of colonic tumour subsite in the index patient, and it is greatest for relatives of younger age index cases.

Short TitleAliment Pharm Ther
Alternate JournalAliment Pharm Ther<br/>Aliment Pharm Ther