Introduction
The risk of colorectal advanced adenomas (CAAs) and colorectal cancer (CRC) in siblings aged ≤ 50 years of patients diagnosed with early-onset CAAs (E-CAAs), defined as having CAA at or below the age of 50 years, is poorly understood.
Aims & Methods
This study aimed to compare the risks of adenomas, CAA, and CRC in siblings aged ≤ 50 years of patients diagnosed with E-CAA to those in individuals aged ≤ 50 without such a family history.
This case-control study was conducted at a tertiary hospital in Vietnam. The participants included 96 cases who were siblings aged ≤ 50 years of patients diagnosed with E-CAA. Controls were randomly selected from consecutive patients aged ≤ 50 years who did not have siblings diagnosed with E-CAA. The absence of a family history of CAA in the control group was confirmed through comprehensive history taking. The controls were matched to cases in a 2:1 ratio for age (±3 years), sex, and smoking status. Individuals with alarming features of CRC or a family history of CRC were excluded. All the participants underwent standard bowel preparation and colonoscopy.
Results
The mean age was similar between cases (40.9 ± 6.0 years) and controls (41.1 ± 6.0 years). Except for the indications for colonoscopy, there were no significant differences in the baseline demographics between the two groups. A higher risk of CAA was documented in cases compared with controls (odds ratio [OR] = 6.33; 95% confidence interval [CI], 1.43–43.8; P = 0.018). This increased risk of CAA was more pronounced among male participants (OR = 13.7; 95% CI, 1.23–262; P = 0.006). Higher risks of colorectal adenomas (OR = 2.43; 95% CI, 1.27–4.67; P = 0.009) and colorectal neoplasia (OR = 2.23; 95% CI, 1.24–4.40; P = 0.011) were also found in cases compared with controls. CRC was found in one case and two controls.
Conclusion
Siblings aged ≤ 50 years of patients diagnosed with E-CAA have an increased risk of adenomas, CAA, and colorectal neoplasia. CRC screening should be initiated early in high-risk individuals.
Table 1. Risk of Colorectal Neoplasia among Siblings of Patients Diagnosed with Advanced Adenomas (n = 288)
| Colorectal neoplasiaa | Cases
(n = 96) | Matched controls
(n = 192) | P valueb | OR (95% CI) |
| All colorectal neoplasia | 24 (25.0) | 24 (12.5) | 0.011 | 2.23 (1.24 – 4.40) |
| Adenomas | 23 (24.0) | 22 (11.5) | 0.009 | 2.43 (1.27 – 4.67) |
| Multiple adenomasc | 5 (5.2) | 0 | 0.004 | - |
| Advanced adenomad | 6 (6.3) | 2 (1.0) | 0.018 | 6.33 (1.43 – 43.8) |
| Adenomas ≥ 10 mm | 6 (6.3) | 2 (1) | 0.018 | 6.33 (1.43 – 43.8) |
| Tubulovillous or villous | 0 | 1 (0.5) | 1 | - |
| High-grade dysplasia | 0 | 1 (0.5) | 1 | - |
| Colorectal cancer | 1 (1.0) | 2 (1.0) | 1 | 1.00 (0.05 - 10.6) |
| Advanced colorectal neoplasiae | 7 (7.3) | 4 (2.1) | 0.046 | 3.70 (1.09 – 14.4) |
aData are presented as No. (%).
bFisher's exact test.
cMultiple adenomas: ≥ 3 adenomas.
dAdvanced adenoma: Adenomas ≥1 cm, adenomas with villous elements ≥ 25% or high-grade dysplasia.
eAdvanced colorectal neoplasia: Advanced adenoma or colorectal cancer.
Bold values: P < 0.05.
References
Ng SC, Lau JY, Chan FK, et al. Risk of Advanced Adenomas in Siblings of Individuals With Advanced Adenomas: A Cross-Sectional Study. Gastroenterology. 2016;150(3):608-e17.
Cottet V, Pariente A, Nalet B, et al. Colonoscopic screening of first-degree relatives of patients with large adenomas: increased risk of colorectal tumors. Gastroenterology. 2007;133(4):1086-1092.
