Cumulative incidence and risk factors for pouch adenomas associated with familial adenomatous polyposis following restorative proctocolectomy

Table 1 Characteristics of familial adenomatous polyposis patients analyzed in this study

Variable
Age at time of IPAA [yr, median (IQR)]	32 (24-41)
Sex, n (%)
Male	52 (54.7)
Female	42 (45.3)
No. of colorectal polyps [n, median (IQR)]	350 (150-700)
Type of anastomosis, n (%)
Hand-sewn with mucosectomy	72 (75.8)
Double stapling	23 (24.2)
No. of surveillances [n, median (IQR)]
Upper GI endoscopy	5 (2-8)
Sigmoidoscopy	5 (3-7)
Pouch adenomas, n (%)	24 (25.3)
Time to pouch adenoma onset [mo, median (IQR)]	52 (28.3-114.3)
ATZ adenomas, n (%)	7 (7.4)
Gastric polyps, n (%)	70 (73.7)
Duodenal adenomas, n (%)	46 (48.5)
Spigelman stage, n (%)
I	24 (25.3)
II	12 (12.6)
III	10 (10.5)
IV	0
Missing data	49 (51.6)
Desmoid tumors, n (%)	23 (24.2)
Colorectal cancer at time of IPAA, n (%)	43 (45.3)
Colon	24 (55.8)
Rectum	19 (44.2)

IPAA: Ileal pouch anal anastomosis; IQR: Interquartile range; ATZ: Anal transition zone; GI: Gastrointestinal.

Table 2 Clinical characteristics of study patients according to presence of pouch adenomas

Characteristic	Presence of pouch adenomas (n = 24)	Absence of pouch adenomas (n = 71)	P value
Age at time of IPAA [yr, median (IQR)]	29 (20-40)	32 (26-41)	0.10
Sex (male), n (%)	16 (66.7)	36 (50.7)	0.17
No. of colorectal polyps [n, median (IQR)]	700 (325-1000)	250 (110-500)	0.001
Colorectal polyps < 1000, n (%)	16 (66.7)	64 (90.1)	0.006
Colorectal polyps ≥ 1000, n (%)	8 (33.3)	7 (9.9)
Time interval after IPAA [mo, median (IQR)]	142 (106-199)	116 (91-175)	0.01
Mucosectomy, n (%)	19 (79.2)	53 (74.6)	0.66
Gastric polyps, n (%)	19 (79.2)	51 (71.8)	0.49
Gastric polyp burden, n (%)			0.31
< 20	13 (54.2)	41 (57.7)
20-49	0	11 (15.5)
≥ 50	6 (25.0)	0
Duodenal adenomas, n (%)	16 (66.7)	30 (42.3)	0.039
Spigelman stage, n (%)			0.30
I	6 (37.5)	18 (60.0)
II	6 (37.5)	6 (20)
III	4 (25.0)	6 (20)
Desmoid tumor, n (%)	4 (16.7)	19 (26.8)	0.32
NSAIDs use, n (%)	1 (4.2)	14 (19.7)	0.07
Colorectal cancer, n (%)	9 (37.5)	34 (47.9)	0.38

IPAA: Ileal pouch anal anastomosis; NSAIDs: Nonsteroidal anti-inflammatory drugs; IQR: Interquartile range.

Table 3 Risk factors associated with pouch adenoma-free survival

Variable	Univariate analysis		Multivariable analysis
	HR (95%CI)	P value	HR (95%CI)	P value
Age	0.97 (0.93-1.01)	0.12
Sex (male)	1.46 (0.62-3.44)	0.39
No. of colorectal polyps (≥ 1000)	2.80 (1.18-6.63)	0.019	2.49 (1.04-5.96)	0.041
Time interval after IPAA	0.996 (0.99-1.003)	0.29
Mucosectomy	1.54 (0.56-4.24)	0.40
Gastric polyps	1.73 (0.64-4.68)	0.28
Duodenal adenoma	2.31 (0.99-5.41)	0.54	2.08 (0.88-4.93)	0.10
Spigelman stage		0.15
I-II	2.27 (0.92-5.55)	0.07
III-IV	2.46 (0.73-8.25)	0.14
Desmoid tumor	0.82 (0.28-2.44)	0.72
NSAID use	0.29 (0.04-2.13)	0.22
Colorectal cancer	0.58 (0.25-1.37)	0.21

IPAA: Ileal pouch anal anastomosis; NSAIDs: Nonsteroidal anti-inflammatory drugs; HR: Hazard ratio; CI: Confidence interval.