Frequency of a positive family history of colorectal cancer in general practice: a cross-sectional study.

BACKGROUND: Evidence on the frequency of a positive family history of colorectal cancer (CRC) among individuals aged <55 years is lacking. General practice setting might be well suited for the identification of individuals in this above-average risk group.

OBJECTIVE: To determine the frequency of a reported positive family history of CRC among patients aged 40 to 54 years in a general practice setting.

METHODS: We conducted a cross-sectional study in 21 general practices in Germany. Patients aged 40 to 54 years were identified by means of the practice software and interviewed by health care assistants using a standardized four-item questionnaire. Outcome was occurrence of a positive family history of CRC, defined as at least one first-degree relative (FDR: parents, siblings, or children) with CRC. Further measurements were FDRs with CRC / colorectal polyps (adenomas) diagnosed before the age of 50 and occurrence of three or more relatives with colorectal, stomach, cervical, ovarian, urethel or renal pelvic cancer.

RESULTS: Out of 6723 participants, 7.2% (95% confidence interval [CI] 6.6% to 7.8%) reported at least one FDR with CRC and 1.2% (95% CI 0.9% to 1.5%) reported FDRs with CRC diagnosed before the age of 50. A further 2.6% (95% CI 2.3% to 3.0%) reported colorectal polyps in FDRs diagnosed before the age of 50 and 2.1% (95% CI 1.8% to 2.5%) reported three or more relatives with entities mentioned above.

CONCLUSION: One in 14 patients reported at least one FDR with CRC. General practice should be considered when defining requirements of risk-adapted CRC screening.