Survival after inflammatory bowel disease-associated colorectal cancer in the Colon Cancer Family Registry

Table 1 Participant characteristics of colorectal cancer cases at enrollment in the Colon Cancer Family Registry according to self-reported diagnosis of inflammatory bowel disease n (%)

Characteristics	Inflammatory bowel disease		P value
	No	Yes
	(n = 6952)	(n = 250)
Age at CRC diagnosis (yr)			< 0.001
< 47	1731 (25)	98 (39)
47-55	1791 (26)	68 (27)
56-65	1803 (26)	42 (17)
> 65	1627 (23)	42 (17)
Female	3515 (51)	133 (53)	0.4
Lifetime endoscopies			< 0.001
None or one	2697 (39)	40 (16)
Two	2004 (29)	51 (20)
Three or more	2251 (32)	159 (64)
Colon CFR recruitment phase			0.4
I (1997-2001)	4310 (62)	161 (64)
II (2002-2009)	2642 (38)	89 (36)
Colon CFR center			< 0.01
Ontario, Canada	1775 (26)	89 (36)
Southern California, United States	1551 (22)	39 (16)
Melbourne, Victoria, Australia	718 (10)	20 (8)
Hawaii, United States	348 (5)	6 (2)
Mayo Clinic, MI, United States	499 (7)	16 (6)
Seattle, WA, United States	2061 (30)	80 (32)
Education1			0.8
Secondary or less	3367 (49)	123 (50)
More than secondary	3518 (51)	124 (50)
Cigarette smoking history12			0.02
Never	3022 (44)	130 (52)
Current	1259 (18)	44 (18)
Former	2650 (38)	75 (30)
Race1			< 0.01
White	5033 (74)	200 (83)
Other	1769 (26)	42 (17)
BMI (kg/m2)12			< 0.01
≤ 23.6	1685 (25)	85 (34)
23.7-26.5	1710 (25)	59 (24)
26.6-30.3	1726 (25)	51 (21)
≥ 30.4	1739 (25)	53 (21)
Regular NSAID user12			0.7
Yes	2719 (40)	95 (39)
No	4159 (60)	151 (61)
1st degree family history of CRC	1495 (22)	35 (14)	< 0.01
Tumor site			< 0.01
Proximal colon	2346 (34)	109 (44)
Distal colon or rectum	4276 (62)	136 (54)
Overlapping/not specified	328 (5)	5 (2)
Microsatellite instability1			0.1
None or low	3743 (88)	150 (87)
High	507 (12)	22 (12)
CRC stage at diagnosis13			0.4
Local	3088 (47)	110 (46)
Regional	2441 (37)	98 (40)
Distant	1080 (16)	34 (14)

¹Numbers do not sum to total due to missing values;

²2 years prior to colorectal cancer (CRC) diagnosis;

³Mean of 50 imputed datasets. Colon CFR: Colon Cancer Family Registry; NSAID: Non-steroidal anti-inflammatory drugs; BMI: Body mass index.

Table 2 Adjusted hazard ratios and 95%CI for death, either with complete available time-at-risk or with follow-up ended 5 years after colorectal cancer diagnosis

	n	Deaths	aHR1 (95%CI)	n	Deaths	aHR2 (95%CI)	n	Deaths	aHR13 (95%CI)
Complete follow-up
No IBD	6952	2013	Ref.	6567	1926	Ref.	3836	1322	Ref.
IBD	250	74	1.08 (0.85-1.36)	242	71	1.09 (0.85-1.40)	81	26	1.20 (0.81-1.79)
P value			0.54			0.48			0.36
5-yr follow-up
No IBD	6903	1372	Ref.	6526	1320	Ref.	3801	871	Ref.
IBD	249	63	1.36 (1.05-1.76)	241	60	1.34 (1.02-1.77)	81	24	1.52 (1.00-2.30)
P value			0.018			0.037			0.048

¹Adjusted for age, recruitment phase, sex, and endoscopy;

²Additional adjustment for surveillance epidemiology and end results summary stage (local, regional, distant);

³Inflammatory bowel disease (IBD) confirmed from medical and pathology records at Seattle and Ontario centers only, non-IBD associated cases restricted to these centers. aHR: Adjusted hazard ratio.