New clinical characteristics of bilateral thyroid cancer        CHEN Zhen-yu, WU Yi. Department of  Head and Neck Surgery, Cancer Hospital, FuDan University, Shanghai 200032, China
Corresponding author: WU Yi, E-mail: ywu@rddb . shanghai.gov.cn
Abstract    Objective    To discuss the new clinical characteristics of bilateral thyroid cancer. Methods    Clinical data of 26 cases of bilateral thyroid cancers from the year of 1999 were compared retrospective with 130 cases of their counterparts from the year of 2009 and so it was with the clinic-pathologic data of 16 cases from the year of 1999 and 104 cases from the year of 2009. Results    There were 26 cases of bilateral thyroid cancers  including 16 cases of synchronous bilateral thyroid cancers  and 10 cases of metachronous bilateral thyroid cancers  from the year of 1999 ; There were 130 cases of  bilateral thyroid cancers including 104 cases of synchronous bilateral thyroid cancers  and 26 cases of metachronous bilateral thyroid cancers  from the year of 2009. There were 2 cases of bilateral micro-carcinoma (12.5%)  and 5 cases of mono-lateral micro-carcinoma（31.2%） in the group of synchronous bilateral thyroid cancers in 1999; There were 28 cases of bilateral micro-carcinoma (26.9%)  and 80 cases of mono-lateral micro-carcinoma（77%）in its counterpart in 2009. In the group of 104 synchronous bilateral thyroid cancers in 2009, central neck lymph node metastases occur in 70% cases, percentage of lateral neck involvement was 13.3% in cases with negative central neck and 56% in cases with involved central neck. Conclusion    The constituent ratio of bilateral thyroid cancers had changed in the year of 2009 compared with that of 1999 which might be due to the general application of ultrasound and its improved accuracy. Routine central node dissection should be carried out and lateral neck should be carefully checked.