Erratum to: Int J Clin Oncol (2016) 21:808–816 DOI 10.1007/s10147-016-0949-1

Unfortunately, the ethical statement was not included in the original publication of the article. The statement is given below.

The research was carried out according to the principles set out in the Declaration of Helsinki 1964 and all subsequent revisions, and the institutional review board at Saitama Medical University International Medical Center had approved the study (Application Number: 11-050).