Incidence of Advanced Neoplasia Low Regardless of Family Colorectal Cancer History

Advanced neoplasia had a low incidence regardless of family history of colorectal cancer (CRC), with older age being a higher risk factor instead, according to a study published in Digestive Diseases and Sciences.

Large and small intestine | Image Credit: Tom - stock.adobe.com

Family history has been identified as a risk factor for CRC and depends on the number of relatives with CRC. Individuals with an average risk who have an adenoma detected on a colonoscopy have a higher risk of advanced neoplasia (AN) on colonoscopies thereafter. The new study assessed an Australian cohort to determine the incidence of AN in individuals with a family history of CRC where an index colonoscopy found no neoplasias.

The Southern Co-operative Program for the Prevention of Colorectal Cancer database was used to collect data for the retrospective cohort study. Participants were included if they had a family history of CRC, had normal or non-neoplastic findings on an index colonoscopy, and had 10 years or more of follow-up colonoscopies from 2000 to 2019. All procedures took place at public hospitals. Participants were excluded if they did not have enough family history information or if their index or final colonoscopy was of poor quality or indeterminate pathology.

All colonoscopies were analyzed for confirmed AN. All pathologies were separated into 5 groups of colorectal adenocarcinoma, advanced adenoma, non-advanced adenoma, non-neoplastic pathologies, and normal.

There were 425 participants included in the study who had a mean (SD) age of 49.4 (9.4) years, and 64.7% of participants were female. The median time to follow-up colonoscopy from the index colonoscopy was 13.5 (IQR, 11.5-16.0) years, and participants underwent a median of 4 (range, 2-10) colonoscopies overall. A total of 30.6% of participants had near-average risk due to family history, 59.8% had moderate risk, and 9.7% had high risk.

There was a total AN incidence of 14.4% (n = 61). The first follow-up colonoscopy resulted in the near-average group having a higher incidence of AN (9.6%) compared with the moderate risk category (5.0%) and the high-risk category (5.3%), but this was not statistically significant. A total of 19.2% of patients with near-average risk developed AN compared with patients of moderate risk (12.2%) and patients of high risk (12.2%). The finding of AN occurred at a younger mean (SD) age for patients of high risk (59.3 [10.2] years) compared with the moderate risk group (61.9 [9.8] years) and near-average risk group (64.8 [7.9] years).

Family history and gender of the patient were not found to affect the risk of AN in the multivariable analysis. Patients who were aged 60 years and older had a higher risk of AN compared with patients who were aged less than 40 years (HR, 4.14; 95% CI, 1.33-12.89).

There were only 4 participants who showed adenocarcinoma, with 3 of them in the moderate risk group and 1 in the near-average risk group. The absence of AN at a follow-up colonoscopy was found to be associated with a lower risk of AN moving forward, with the risk of developing AN being lower if the participant had 2 follow-up colonoscopies done (HR, 0.08; 95% CI, 0.04-0.18). The risk went down through each subsequent negative colonoscopy.

There were some limitations to this study. There was a reliance on self-reporting family history of CRC and it was not verified through medical records. The study was also retrospective and may have missed patients who exited the surveillance early and could have led to a healthy person bias. The study also covered different guidelines for each patient depending on when they entered the study, due to the 20-year time period. Other risk factors could not be unaccounted for, and there was no control group.

The researchers concluded that family history may not be a significant risk factor in AN compared with what was previously thought, especially if a person has had a normal colonoscopy in the past.

Reference

Barnett MI, Wassie MM, Cock C, Bampton PA, Symonds EL. Low incidence of colorectal advanced neoplasia during surveillance in individuals with a family history of colorectal cancer. Dig Dis Sci. Published online September 8, 2023. doi:10.1007/s10620-023-08053