Colorectal cancer screening in patients at moderately increased risk due to family history

Table 1 Colorectal cancer screening guidelines for patients with a family history[2-4]

Family history	ACG			ASGE			AGA
	Screening initiation age (yr)	Screening modality	Screening intervals (yr)	Screening initiation age (yr)	Screening modality	Screening intervals (yr)	Screening initiation age (yr)	Screening modality	Screening intervals (yr)
2 FDRs with neoplasia3	401	Colonoscopy	5	-	-	-	401	Colonoscopy	5
1 FDR with CRC < 603	401	Colonoscopy	5	401	Colonoscopy	3-5	401	Colonoscopy	5
1 FDR with CRC ≥ 603	50	Any	Average risk	40	Colonoscopy	10	40	Any	Average risk
1 FDR with adenoma < 60	50	Any	Average risk	401	Colonoscopy	5	401	Colonoscopy	5
1 FDR with adenoma ≥ 60	50	Any	Average risk	Not specified	Colonoscopy	10	40	Any	Average risk
2 SDRs with CRC2	-	-	-	50	Any	Average risk	40	Any	Average risk

¹40 years old or 10 years younger than the age of diagnosis of the youngest affected relative, whichever is younger;

²One second-degree relative (SDR) or third-degree relative in the case of the American Society of Gastrointestinal Endoscopy (ASGE) recommendations;

³For the American College of Gastroenterology (ACG), either colorectal cancer (CRC) or advanced neoplasm (tubular adenoma ≥ 1 cm or any adenoma with villous or high-grade dysplastic features). The notation “1 first-degree relative (FDR) with CRC < 60” means “colorectal cancer in a first-degree relative with age of onset younger than 60 years”. AGA: American Gastroenterological Association.

Table 2 Relative risk of colorectal cancer occurrence in a proband associated with different constellations of family history[33]

No. of FDRs with CRC	No. of SDRs with CRC	No. of TDRs with CRC	Relative risk (95% CI)
1	0	0	1.76 (1.63-1.89)
2	-	-	3.01 (2.66-3.38)
0	2	-	1.20 (1.05-1.38)
1	1	-	2.12 (1.90-2.35)
1	2	-	2.31 (1.80-2.93)
0	1	2	1.33 (1.13-1.55)

FDR: First-degree relative; SDR: Second- degree relative; TDR: Third- degree relative; CI: Confidence interval; CRC: Colorectal cancer.