A. A. Kirshin
Republican Clinical Oncology Dispensary named after Professor M.Z. Sigal
Russian Federation

Aleksandr A. Kirshin, Abdominal surgeon, oncologist, chief transplant specialist at the Ministry of Health of the Republic of Tatarstan, deputy chief physician for medical affairs 
Author's contribution: development of the study concept, formulation of the study objectives, access to sources, analysis and summarization of the obtained data.

Sibirsky Trakt St., 29, Kazan, 420029

L. I. Ziganshin
Republican Clinical Hospital
Russian Federation

Lenar I. Ziganshin, Surgeon, oncologist, endoscopist, Head of the Surgery Department No. 2 
Author's contribution: access to sources, analysis and summarization of the obtained data.

Orenburgsky Trakt St., 138, Kazan, 420064

B. A. Sakhabetdinov
Kazan State Medical University
Russian Federation

Bulat A. Sakhabetdinov, Assistant Professor, Department of Operative Surgery and Topographic Anatomy 
Author's contribution: reviewing sources, analyzing, and summarizing the obtained data.

Butlerova St., 49, Kazan, 420012

D. R. Usmanova
Kazan State Medical University
Russian Federation

Diana R. Usmanova, Resident, Department of Surgical Diseases 
Author's contribution: reviewing sources, analyzing, and summarizing the obtained data.

Butlerova St., 49, Kazan, 420012

A. S. Bobrikhin
Kazan State Medical University
Russian Federation

Anastasiya S. Bobrikhina, Student, Faculty of Pediatrics 
Author's contribution: reviewing sources, analyzing, and summarizing the obtained data.

Butlerova St., 49, Kazan, 420012