Efficacy and safety of intraoperative radiotherapy in rectal cancer: A systematic review and meta-analysis

Table 1 Baseline characteristics of the included studies

Ref.	Year	Location	Time frame	Type	Patients, n IORT/ non-IORT	Age in yr, mean IORT non-IORT	Follow-up in mo, mean IORT non-IORT	Resection margin	Clinical stages, %	PR-RT, %	CT, %	PO-RT, %	IORT dose in Gy mean	NOS score
Willett et al[23]	1991	United States	1978-1988	Observational studies	20; 21/22; 2	64 v	26 v	R0; R1/R2	NA	100	NA	0	15	7
Suzuki et al[24]	1995	Germany	1981-1988	Observational studies	42/64	64.3 v	44 v	R1/R2	NA	NA	NA	98	20	8
Huber et al[25]	1996	Germany	1989-1993	Observational studies	36/18	NA	25.5 v	R0/R1/R2	T3 (50); T4 (50)	50	100	50	15	8
Wiig et al[26]	2002	Norway	1990-1999	Observational studies	59/48	NA	NA	R0/R1/R2	NA	100	NA	NA	15-20	8
Ratto et al[27]	2003	Italy	1990-1997	Observational studies	19/24	62	74 v	NA	T3 (7); T4 (93)	NA	NA	NA	10-15	7
Sadahiro et al[28]	2004	Japan	1991-2001	Observational studies	99/68	60 61	67 v	NA	T1/T2 (29); T3 (59); T4 (12)	100	53	0	17.3	7
Ferenschild et al[29]	2006	Netherlands	1987-2001	Observational studies	30/93	66 v	25 v	R0	T2 (14); T3 (57); T4 (25)	100	NA	0	10	9
Masaki et al[30]	2008	Japan	2000-2007	RCT	19/22	NA	34 v	NA	T1/T2 (11); T3 (89)	NA	37	NA	18-20 f	RCT
Valentini et al[31]	2009	Italy	1991-2006	Observational studies	11/35	62 v	80 v	R0	T4 (100)	NA	NA	NA	10-15 f	7
Dubois et al[32]	2011	France	1993-2001	RCT	72/68	62.5 64.5	60 v	NA	T3/T4 (100)	100	25	NA	18	RCT
Zhang et al[35]	2014	China	1996-2007	Observational studies	45/46	61 61	72.9 v	NA	T3 (100)	NA	100	51	20	8
Alberda et al[33]	2014	Netherlands	1996-2012	Observational studies	21; 22/31; 17	66 59/61 56	38 39/23 12	R0/R1	T3 (41); T4 (59)	NA	NA	NA	10	8
Klink et al[34]	2014	Germany	2004-2012	Observational studies	52/111	62 63	NA	R0	T3/T4 (100)	NA	NA	NA	10-20 f	9
Zhang et al[36]	2015	China	1994-2007	Observational studies	71/77	58 63	72.3 v	R0/R1/R2	T2 (6); T3 (52); T4 (42)	NA	100	100	15	7
Masaki et al[19]	2020	Japan	2000-2017	RCT	38/38	NA	72 v	R0/R1	T1/T2 (17); T3 (80); T4 (3)	NA	NA	NA	18-20 f	RCT

CT: Chemotherapy; f: Range reported with no mean/median; IORT: Intraoperative radiotherapy; NA: Not reported; non-IORT: Non-intraoperative radiotherapy; PO-RT: Post-operative radiotherapy; PR-RT: Pre-operative radiotherapy; RCT: Randomized controlled trial; v: Reported for IORT and non-IORT combined.