Table 1.

Information on 18 studies included in the analysis

Study	Year	Recruitment years	Total ACC cases	Cases of neck dissection	Cervical lymph node metastases (pN+)	Metastatic rate, %
Bhayani et al5	2012	1990–2007	30	30	7	23.3
Amit et al7	2015	1985–2011	270	270	79	29.3
Min et al2	2012	1995–2009	616	—	62	10.1
Liu et al13	2015	2000–2013	272	272	58	21.3
Megwalu and Sirjani3	2017	1988–2013	720	—	126	17.5
Mücke et al14	2010	1992–2006	33	18	8	24.2
van Weert et al15	2013	1979–2009	105	—	11	10.5
Jang et al16	2017	1991–2013	61	—	8	13.1
Ali et al17	2017	1985–2009	87	30	10	11.5
Meyers et al18	2016	2009–2012	87	—	9	10.3
Bjørndal et al8	2015	1990–2005	71	—	12	16.9
Ko et al19	2016	2000–2014	60	—	7	11.7
Hämetoja et al20	2017	1974–2012	17	17	4	23.5
Mannelli et al21	2017	1980–2005	44	—	8	18.2
Ouyang et al22	2016	1990–2015	228	—	21	9.2
Zhang et al23	2013	2000–2007	218	—	29	13.3
Kruse et al24	2010	1999–2008	13	—	3	23.1
Lee et al25	2014	1991–2009	61	30	11	18.0
Total cases			2993		473

Note: “—”, Data not provided.

Abbreviations: ACC, adenoid cystic carcinoma; pN+, pathological node positive.