the incidence is 1.2 % ( 12/943 ) of laryngeal carcinomas , 1.3 % ( 12/904 ) of multiple primary cancers , 1.4 % ( 12/873 ) of double primary cancers and 39 % ( 12/31 ) of double primary cancers related to laryngeal cancers .
C0595989
laryngeal carcinomas
C0023078
laryngeal