eTable 2. Trends in the incidence of early-onset colorectal cancer (20–49 years) by 10-year age group, sex, and diagnosis in different subsites of the colon in Germany (Bremen, Hamburg, Münster, Rhineland–Palatinate, Saarland, and Schleswig–Holstein) from 1999 to 2018.

Site /colonic subsite (ICD-10) and age group (years)	Males			Females			Total
	AAPC	95% CI	Trend	AAPC	95% CI	Trend	AAPC	95% CI	Trend
Colon (C18)
20–29	4.30	[1.76; 6.90]	Increasing	5.71	[2.26; 9.28]	Increasing	5.05	[2.51; 7.66]	Increasing
30–39	2.74	[1.49; 4.01]	Increasing	2.65	[1.14; 4.19]	Increasing	2.70	[1.72; 3.69]	Increasing
40–49	0.96	[−0.12; 2.05]	Stable	0.28	[−0.62; 1.19]	Stable	0.65	[−0.09; 1.40]	Stable
Proximal colon (C18.0–C18.4)
20–29	NA	NA	NA	7.10	[2.18; 12.29]	Increasing	6.85	[4.21; 9.55]	Increasing
30–39	4.10	[2.42; 5.80]	Increasing	5.53	[3.87; 7.22]	Increasing	4.82	[3.77; 5.89]	Increasing
40–49	2.22	[0.73; 3.74]	Increasing	0.76	[−0.51; 2.05]	Stable	1.56	[0.78; 2.35]	Increasing
Distal colon (C18.5–C18.7)
20–29	NA	NA	NA	NA	NA	NA	NA	NA	NA
30–39	2.26	[−1.26; 5.91]	Stable	−0.15	[−2.76; 2.53]	Stable	0.95	[−1.02; 2.96]	Stable
40–49	0.62	[−0.54; 1.79]	Stable	0.61	[−0.72; 1.94]	Stable	0.61	[−0.43; 1.66]	Stable
Rectum (C19–C20)
20–29	5.08	[0.64; 9.72]	Increasing	NA	NA	NA	7.02	[3.11; 11.09]	Increasing
30–39	1.54	[−0.32; 3.44]	Stable	2.47	[0.31; 4.68]	Increasing	1.90	[0.63; 3.18]	Increasing
40–49	0.09	[−0.78; 0.97]	Stable	0.60	[−0.26; 1.48]	Stable	0.31	[−0.37; 0.99]	Stable

AAPC, Average annual percentage change; 95% CI, 95% confidence interval; NA, no trend reported due to years with no cases;

ICD-10, Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems