Table 2.

Comparison of OS and deaths within 25 months between young (ages 18–44 years) and old (ages 44–60, 60–70, and 70–80 years) patients with colorectal cancer

Age group	OS			Deaths within 25 mo
	No. of patients	OS, %	HR (95% CI)a	No. of deaths	Proportion of deaths occurred within 25 mo, %	OR (95% CI)b
All stages
Young group, yr
18–44	253	77.1		58	63.8
Old group, yr
44–60	1,784	78.5	1 (Reference)	383	40.7	1 (Reference)
60–70	2,078	75.4	1.25 (1.09–1.42)	511	42.7	1.09 (0.83–1.42)
70–80	1,342	66.7	1.75 (1.52–2.01)	447	43.6	1.12 (0.85–1.48)
Stage I
Young group, yr
18–44	31	96.8		1	0
Old group, yr
44–60	279	95.7	1 (Reference)	12	0	NAc
60–70	324	92.6	1.76 (0.88–3.52)	24	12.5
70–80	203	86.2	3.39 (1.71–6.69)	28	14.3
Stage II
Young group, yr
18–44	102	92.2		8	50
Old group, yr
44–60	706	90.5	1 (Reference)	67	19.4	1 (Reference)
60–70	856	84.6	1.76 (1.30–2.37)	132	24.2	1.31 (0.64–2.72)
70–80	600	78.8	2.50 (1.85–3.39)	127	25.2	1.37 (0.66–2.83)
Stage III
Young group, yr
18–44	98	69.4		30	56.7
Old group, yr
44–60	696	68.4	1 (Reference)	220	36.8	1 (Reference)
60–70	778	67.0	1.15 (0.96–1.38)	257	44.7	1.39 (0.96–2.01)
70–80	447	52.3	1.75 (1.45–2.11)	213	49.3	1.67 (1.14–2.45)
Stage IV
Young group, yr
18–44	22	13.6		19	84.2
Old group, yr
44–60	103	18.4	1 (Reference)	84	73.8	1 (Reference)
60–70	120	18.3	1.03 (0.76–1.39)	98	69.4	0.80 (0.42–1.54)
70–80	92	14.1	0.98 (0.71–1.35)	79	68.4	0.77 (0.39–1.51)

CI, confidence interval; HR, hazard ratio; MMR, mismatch repair; NA, not applicable; OR, odds ratio; OS, overall survival.

^aMultivariable Cox regression model adjusted for sex, differentiation grade, location, perineural invasion, vascular invasion, and MMR status.

^bMultivariable logistic regression model adjusted for sex, differentiation grade, location, perineural invasion, vascular invasion, and MMR status.

^cHR not calculable owing to 0 event in this subgroup.