Table 1.

Characteristics of the included studies

First author	Year	Country	Setting	Sampling method	Survey method	Response, %	Response, n	Medical specialist, n	Citation
Rosenbaum	2002	USA	The University of Iowa College of Medicine	Random	Postal	18.4%	690	265	[35]
Hyodo	2003	Japan	The Japanese oncology literature and the Nationwide association of medical centers for cancer and adult diseases	Random	Postal	66.7%	54	52	[36]
Kemper	2004	USA	The American Academy of Pediatrics	Random	Online	19.5%	195	195	[37]
Kolstad	2004	Norway	Five university oncology units in Norway	Random	Postal	38.5%	751	751	[5]
Risberg	2004	Norway	Five reginal oncology centers	Random	Postal	15.4%	104	104	[38]
Samano	2005	Brazil	Effective physician members of the Brazilian Cancer Society	Random	Postal	61.5%	509	108	[39]
Sawni	2007	USA	The American Academy of Pediatrics	Random	Postal	31.5%	268	263	[40]
Lee	2008	USA, China, and Taiwan	The Northern California Tumor Board meeting, China Medical University, Sun-Yat Sen Cancer Center Taiwan, Peking University Cancer Hospital China, and Peking Union Hospital China	Random	Postal	38.0%	95	95	[15]
Mak	2009	Australia	The Australasian Faculty of Rehabilitation Medicine, The Royal Australasia College of Physicians	Random	Online	38.3%	36	36	[41]
Wu	2009	USA	The Washington State of Association of Neurological Surgeons	Random	Online	67.0%	65	65	[42]
Manek	2010	USA	The practicing rheumatologists in the United States	Random	Postal	40.3%	381	381	[6]
Kundu	2011	USA	The Seattle Children’s Hospital	Random	Online	43.7%	213	213	[43]
Tempest	2011	England	A urologist practicing in three English training deaneries	Random	Online and Phone	13.4%	88	88	[44]
Vlieger	2011	Netherlands	The Dutch Society of Paediatrics	Random	Online	Not indicated denominator	170	170	[45]
Samuels	2013	Israel	Member of the Obstetricians and gynecologists (board-certified specialists or residents) were recruited from 7 medical centers in Southern, Central, and Northern Israel	Convenience	Not indicated	18.5%	648	648	[46]
Trimborn	2013	Germany	A German employee visiting the occupational health service of the university hospital	Convenience	Not indicated	75.7%	258	258	[8]
Conrad	2014	Germany	The German Society for Palliative Care	Random	Online	86.7%	117	40	[47]
Stewart	2014	Scotland	The care of pregnant women in the Grampian region of North-East Scotland	Random	Online and postal	72.0%	126	96	[48]
Brambila-Tapia	2016	Mexico	The Primary and secondary care hospitals in Guadalajara	Convenience	Not indicated	13.0%	547	120	[49]
Crundwell	2016	UK	The Clinical staff at Cambridge University Hospital’sotolaryngology and audiology departments	Convenience	Not indicated	23.7%	343	343	[10]
Gaboury	2016	Canada	The College des medecins du Quebec	Random	Online	100.0%	207	107	[50]
Mann	2016	USA	pain medicine fellowship at the American College of Graduate Medical Education	Convenience	Online and postal	53.3%	856	856	[7]
Soos	2016	Hungary	Four Hungarian universities and other eleven surgery wards and intensive care departments participated in the study	Convenience	Online and postal	61.5%	509	101	[51]
Stone	2016	Australia	All faculties, fellows, and residents presented at a single anesthesia grand rounds of Johns Hopkins University	Random	Not indicated	70.3%	102	102	[52]
Klein	2017	Germany	The Research Group on Gynecological Oncology of the German Cancer Society	Random	Online	38.1%	24	24	[14]