Table 6. Previous published studies.

Study	N	% accuracy	% T-downstage	% T-upstage	% N-upstage
Stiles 2011	40	12.5	30	40	55
Zhang 2012	14	28.6	42.9	21.4	21.4
Crabtree 2013	482	27.4	25.9	18	44.5
Hardacker 2014	35	8.5	42.8	48.5	40
Shin 2014	66	15	60.6	16.7	39
Tekola 2014	38	21	45	17	50
Speicher 2014	786	26.7	30	27.7	30.2
Dolan 2016	16	6	38	56	52
Markar 2016	285	26	35.7	34.8	50
Current study	1,840	30.7	25.5	25.9	17.9