Patients undergoing colorectal cancer screening underestimate their cancer risk and delay presentation for screening

Abstract

Background: Colorectal cancer (CRC) is the third most common cancer in Canada. Screening guidelines recommend that first-time screening should occur at 50 years of age for average-risk individuals and at 40 years of age for those with a family history of CRC.

Objective: To examine whether persons with a positive CRC family history were achieving screening at 40 years of age and whether average-risk persons were achieving screening at 50 years of age.

Methods: The present study was a cross-sectional analysis of subjects who entered a colon cancer screening program and were undergoing CRC screening for the first time.

Results: A total of 778 individuals were enrolled in the present study: 340 (174 males) with no family history of CRC, and 438 (189 males) with a positive family history of CRC. For the group with a positive family history, the mean (± SD) age for primary screening was 54.4 ± 8.5 years, compared with 58.2 ± 6.4 years for the group with no family history. On average, those with a positive family history initiated screening 3.8 years (95% CI 2.8 to 4.8; P<0.05) earlier than those without. Adenoma polyp detection rate for the positive family history group was 20.8% (n=91) compared with 23.5 % (n=80) for the group with no family history.

Conclusions: Individuals with a positive CRC family history are initiating screening approximately four years earlier than those without a family history; nevertheless, both groups are undergoing screening well past current guideline recommendations.

Figure 1)

Source of referral for colorectal cancer (CRC) screening. A Negative family history of CRC. B Positive family history of CRC. Although more subjects self-initiated the process of screening themselves when having a positive family history of CRC, the vast majority of each group was referred by their family physician

Figure 2)

Subjects’ personal risk of colorectal cancer (CRC). Individuals without a family history of CRC (A) perceive their risk for CRC better than those with a family history of CRC (B). *Denotes the appropriate risk category for each group. Avg Average

Figure 3)

A Education level and subjects’ perceived risk of colorectal cancer (CRC) for individuals with a positive CRC family history. Inappropriately estimated included those subjects who ranked their risk or CRC as below average or average. Appropriately estimated includes those subjects who ranked their risk of CRC as above average risk. It is shown that no matter the education level of the subject, the majority will inappropriately estimate their risk of CRC if they have a positive family history. B Education level and subjects’ perceived risk of CRC for individuals with a negative family history of CRC. Inappropriately estimated included those subjects who ranked their risk of CRC as below average or above average. Appropriately estimated included those subjects who ranked their risk of CRC as average risk. It is shown that no matter the education level of the subject, the majority will appropriately estimate their risk of CRC if they have a negative family history. Values above each bar the are number of subjects in each group. <HS Less than high school education; HS High school education