Study	Reason for exclusion
Atif 2012	Randomised trial of preoperative radiotherapy versus postoperative radiotherapy. Both arms received radiotherapy.
Bosset 2004	Randomised trial of preoperative chemoradiotherapy versus preoperative radiotherapy. Both arms received radiotherapy.
Boulis‐Wassif 1982	Large fields including para‐aortics and only 2 fields
Boulis‐Wassif 1984	Randomised trial of preoperative administration of radiotherapy, with or without 5‐fluorouracil before radical surgery
Bujko 2004	Randomised trial of short‐term radiotherapy vs conventionally fractionated radiochemotherapy
Bujko 2013	Randomised those with early rectal cancer to preoperative short‐course radiotherapy (25 Gy in 5 fractions + 4 Gy boost) or long‐course chemoradiotherapy (55.8 Gy in 31 fractions with concurrent 5‐fluorouracil/leucovorin) followed by local excision. Radical surgery only for poor responders. Excluded given that both arms received radiotherapy, and radical surgery not done for all participants
Camma 2000	Meta‐analysis, preoperative radiotherapy for rectal cancer
CCCG 2001	Systematic review
Cedermark 1995	Large‐field RT with elective para‐aortic node irradiation
Ceelen 2005	Systematic review on preoperative chemoradiotherapy for locally advanced rectal cancer
Cummings 1985	[trial ‐ primary reference]. No data regarding the study. Included in CCCG 2001 review by obtaining individual patient data (no published data available)
Dahl 1990	Large fields with superior border at the top of L1 and only 2 fields
Dubois 2011	Preoperative RT was performed in all participants before randomisation to either surgical resection alone or surgical resection and intraoperative radiation therapy.
Erlandsson 2017	No surgery‐alone arm
Figueredo 2003	Meta‐analysis and practice guideline for Cancer Care Ontario
Francois 2014	ACCORD12/0405 PRODIGE: both arms used preoperative chemoradiotherapy. The experimental arm used additional oxaliplatin.
Frykholm 1993	Randomised trial of preoperative radiotherapy vs postoperative radiotherapy. Both arms received radiotherapy.
Frykholm 2001	Compared chemoradiotherapy vs radiotherapy preoperatively for unresectable rectal cancer. Both arms received radiotherapy.
Gerard 1988	The trial used only 2 fields and large‐field RT with superior border at top of second lumbar vertebra.
Gerard 2004	Randomised trial of preoperative external‐beam radiotherapy (39 Gy in 13 fractions over 17 days) vs the same external‐beam radiotherapy with boost (85 Gy in 3 fractions) using endocavitary contact X‐ray
Gerard 2011	Both arms received radiotherapy.
Glehen 2003	Randomised trial of short‐interval (2 weeks) preoperative radiotherapy vs long‐interval (4 to 6 weeks)
Goldberg 1994	The trial used low RT dose (15 Gy in 3 fractions) and only 2 fields.
Guckenberger 2012	Both arms received radiation therapy.
Gunderson 2003	Review article.
Gérard 2012	Both arms received radiation therapy.
Higgins 1975	Patients at enrolment were with evidence of distant metastases.
Higgins 1986	The trial used low RT energy, only 2 fields, and large fields with the superior border at the top of the second lumbar vertebra.
Illenyi 1994	The trial used only 2 fields.
Kim 2011	Radiotherapy was performed postoperatively in all participants. The study compared early (started on the first day of the first chemotherapy cycle) and late RT (started on the first day of the third chemotherapy cycle).
Kimura 1989	No information available regarding fractionation, fields, or field arrangement
Kligerman 1972	The trial used large‐field RT.
Latkauskas 2012	Both arms received radiation therapy.
MRC 1984	The trial used low RT dose (20 Gy in 10 fractions or 5 Gy single fraction) and only 2 fields.
MRC 1996	The trial used only 2 fields.
Ngan 2012	Both arms received radiation therapy. This is a randomised trial comparing short‐course radiotherapy with long‐course chemoradiotherapy.
Niebel 1988	A randomised 3‐arm study: (1) preoperative radiotherapy (25 Gy in 2.5 weeks) with a postoperative boost (25 Gy) for participants with pT3 and pT4 stages; (2) postoperative radiotherapy; and (3) surgery. The authors reported low compliance to postoperative boost without providing numbers: "many patients with pT3/pT4‐stage disease postoperatively refused the intended radiation therapy in spite of having given informed consent or were not radiated for various reasons which reflect the doctor's or the patient's bias". In addition, neither the number of allocated participants in the groups nor the results for the evaluated outcomes were adequately reported.
Parc 2009	Secondary analysis of a randomised trial of 2 different surgical procedures: coloplasty versus J‐pouch. The use of preoperative RT was not randomised, and was left to surgeons’ discretion.
Petersen 1998	The trial used low RT dose (16.5 Gy in 5 fractions).
Pettersson 2015	No surgery‐alone arm
Reis Neto 1989	The trial used large‐field RT.
Rider 1977	The trial used low RT dose (5 Gy).
Rouanet 2006	Both arms received RT. Randomisation between preoperative RT alone (45 + 18 Gy) and preoperative chemoradiotherapy (45 Gy + infusional 5‐fluorouracil)
Sause(RTOG81‐15)1994	Low dose (5 Gy)
Stockholm 1996	316 participants from this trial were included in Swedish RCT 1997, therefore we have excluded this trial to avoid double counting.
Valentini 2008	The study compared 2 different chemoradiotherapy schemes (both arms received radiotherapy).
You 1993	The trial used large‐field RT.
Zehra 2015	This was an abstract of a review about rectal dysfunction and quality of life following curative treatment for rectal cancer.

RT: radiotherapy