Table 1.

Characteristics of included studies

Author and year	Country	Data period	Type of studya	Total number of FAP patients	Number of FAP patients with known APC mutation	Number of FAP patients with ≥ 1 desmoid tumours	Location of desmoid tumoursb			Duration of follow-up (months)
							IA	AW	EA
Tonelli 1997 [29]	Italy	1984–1995	P	39	NR	9	x	x	x	Mean: IRA 81.5, IPAA 61.3
Hizawa 1997 [30]	Japan	1970–1994	R	49	NR	6	x	x		Mean ECc: 92.4
Soravia 1999 [31]	Canada	1980–1997	R	131	NR	13	NRd	NR	NR	Mean: IRA 92.4, IPAA 72
Björk 2001 [18]	Sweden	1984–1996	R	63	NR	2	x			Median: IRA 128, IPAA 84
Ho 2002 [32]	Hong Kong	1995–2001	P	70	NR	11	x	x	x	NR
Sturt 2004 [24]	UK	NR	R	379	379	57	NR	NR	NR	NR
Speake 2007 [23]	UK	NR	R	47	47	18	x	x	x	Cumulative incidence after 72 months
Durno 2007 [17]	Canada	1980–2005	R	887	457	121	NR	NR	NR	NR
Sinha 2010 [15]	UK	1996–2006	R	558	456	49	x			NR
Leal 2010 [16]	Brasil	1984–2008	R	68	NR	9	x	x		Median: IRA 44, IPAA 54
Nieuwenhuis 2011 [6]	Europee	NR	R	2260	1743	220	x	x	x	NR
Turina 2013 [22]	Switzerland	1978–NR	R	37	27	15	x	x	x	NR
Vitellaro 2014 [14]	Italy	1947–2012	R	672	516	101	x	x		Median: open group 132, lap. group 60
Koskenvuo 2015 [13]	Finland	1963–2012	R	228	NR	26	x	x	x	Median: IRA 248.4, IPAA 116.4
Konishi 2016 [12]	Japan	2000–2012	R	256	NR	43	NR	NR	NR	Cumulative incidence after 60 months
Saito 2016 [21]	Japan	2000–2012	R	277	NR	39	x	x		Cumulative incidence after 60 months
Walter 2016 [11]	France	1965–2013	R	180	140	31	x	x	x	Median EC: 228 from FAP diagnosis
Sinha 2018 [33]	UK	1996–2016	R	112	NR	10	x	x		Median: open group 199, lap. group 49
Babaya 2020 [10]	Japan	1981–2017	R	56	NR	9	x	x	x	Median: IRA 138.3, IPAA 199.9
Ashar 2021 [34]	India	2008–2019	R	83	83	15	x	x		NR

a. P = prospective, R = retrospective

b. IA = intra-abdominal/mesenteric, AW = abdominal wall, EA = extra-abdominal

c. EC = entire cohort

d. NR = not reported

e. Centers from the Netherlands, France, Denmark, Finland and Italy