Table 3. Types of databases contributing to the 7^th and 8^th editions of the TNM classification of lung cancer.

Type of database	Number*
	7th edition	8th edition
Clinical trials	24,239	0
Surgical series	19,172	5,965
Registries	16,660	26,122
Series with all treatments	7,866	0
Consortia	5,912	43,637
Institutional registries	5,492	208
Surgical registries	2,154	0
Institutional series	0	1,185
Unknown	0	39
Total	81,495	77,156

*, number after exclusions. TNM, tumor, node and metastasis.