Family History of Cancer and Colon Cancer Risk: the Utah Population Database

Abstract

Family history of colon cancer has been shown to be related to the risk of developing colon cancer. The impact that a comprehensive family history of colon or other cancers has on the risk of colon cancer has not been thoroughly studied. The purpose of this study was to assess the risk of developing colon cancer associated with having a family history of colon, rectal, breast, ovarian, endometrial, or prostate cancer. A case-control study was conducted using data from the Utah Population Database. Case patients had first primary colon cancers (n = 2543). Three control subjects per case were individually matched to case patients on year of birth, place of birth, marital status, and sex. Those case patients with the highest familial standardized incidence ratio were at an increased risk of developing colon cancer (for men, odds ratio [OR] = 2.51 and 95% confidence interval [CI] = 1.88-3.29; for women, OR = 2.90 and 95% CI = 2.17-3.82). A second- or third-degree relative with colon cancer increased risk from 25% to 52%. Risk associated with family history was greater in those patients diagnosed before age 50 (for men, OR = 3.61 and for women, OR = 7.18) than in those diagnosed at 50 or more years of age (for men, OR = 2.44 and for women, OR = 2.73). The risk associated with a family history of colon cancer was greatest for the distal segment of the colon. Women were at an increased risk of colon cancer if they had a first-degree relative with breast (OR = 1.59; 95% CI = 1.25-2.03), uterine (OR = 1.50; 95% CI = 0.99-2.26), ovarian (OR = 1.63; 95% CI = 1.41-1.89), or prostate (OR = 1.49; 95% CI = 1.21-1.82) cancer; men were at increased risk of colon cancer if they had a first-degree relative with breast (OR = 1.30; 95% CI = 1.02-1.66), uterine (OR = 1.96; 95% CI = 1.34-2.87), or ovarian (OR = 1.59; 95% CI = 0.90-2.81) cancer. These findings support previous observations that people with a family history of colon cancer are at increased risk of colon cancer. Those with a second- or third-degree relative with colon cancer or a first-degree relative with breast, ovarian, uterine, or prostate cancer also have an increased risk of developing colon cancer. These data support the recommendations that individuals who have a first-degree, and possibly a second- or third-degree, relative with colon cancer should have regular screening for colon cancer.