Received: 19 February 2021
Accepted: 23 April 2021
First Online: 5 May 2021
: The study was approved by the Ethics Committee of Collegium Medicum Nicolaus Copernicus University (institutional review board) [Approval Number KB/294/20] and proceeded in line with the tenets set by the Declaration of Helsinki. All patients gave their informed consent for endoscopic procedures.
: The authors declare no conflict of interest.