Marmara University, School of Medicine, Istanbul, TurkeyIzmir Katip Celebi University, Izmir, TurkeyHospital Municipal Vila Santa Catarina, Sao Paulo, BrazilHospital Francesco Ferrari, Casarano, ItalyEuroclinic Athens, GreeceKonstantopoulio General Hospital, Athens, GreeceSiberian State Medical University, Tomsk, RussiaUniversity Hospital of Larissa, Larissa, GreeceMonastir University Hospital, Monastir, TunisiaBagcilar Training and Research Hospital, Istanbul, TurkeyHospital Santa Maria delle Croci, Ravenna, ItalyAuckland City Hospital, Auckland, New ZealandLaikon General Hospital, Athens, GreeceUniversity Hospital Alexandrovska, Sofia, BulgariaUniversity Hospital of Padova, Padova, ItalySt. Thomas Teaching Hospital, Guys and St Thomas NHS, LondonHospital Universitario Y Politechnico La Fe, Valencia, SpainDr. Dokuz Eylül Üniversitesi Tıp Fakültesi, Izmir, TurkeyMemorial Hospital, IstanbulFundació Hospital de l’Esperit Sant, BarcelonaHospital Clínico Universitario, Valladolid, SpainLeicester Royal Infirmary, University Hospitals of Leicester NHS TrustGadarif Teaching Hospital, Gadarif City, SudanMaciel Hospital, MontevideoRegional Institute of Oncology, LasiAkademiska Sjukhuset, UppsalaMorgagni-Pierantoni Hospital, ForliLamia General Hospital, Department of Surgery, LamiaMédica Uruguaya, Montevideo, Uruguay Royal Prince Alfred Hospital, Department of Colorectal Surgery, SydneyAminu Kano Teaching Hospital, Kano, NigeriaGastrointestinal Surgery Unit, Istanbul Faculty of MedicineUZ KU Leuven, LeuvenAORN San Pio, UOC Chirurgia Generale ed Oncologica, BenevitoAnkara Bilkent City Hospital of Health Science UniversityLa Rabta University Hospital, Department of Surgery A, TunisErasmus MC, RotterdamRadboud University Medical Center, Nijmegen, the NetherlandsGeneral University Hospital of Patras, Achaia, GreeceGeneral Hospital of Eastern Achaia, Achaia, GreeceUniversity Hospital Gregorio Marañón, Colorectal Surgery Unit, MadridGazi University School of Medicine, Ankara, TurkeyHospital Clínico San Carlos, Madrid, SpainSchool of Medical Sciences & Hospital Universiti Sains Malaysia, Kubang Kerian Kelantan, MalaysiaSurgut District Clinical Hospital, Surgut, RussiaMeander Medisch CentrumUniversity of Health Sciences, Sultan 2. Abdulhamid Han Training and Research Hospital, Istanbul, TurkeyFederal Medical Centre, Department of Surgery, UmuahiaUniversity Hospital Ostrava, Department of Surgery, OstravaYstad Hospital, Department of Surgery, YstandNational Cancer Institute, Vilnius, LithuaniaIRCCS Azienda Ospedaliero-Universitaria di BolognaSomogy County Moritz Kaposi Teaching Hospital, Department of Surgery, KaposvárAretaieion Hospital, 2nd Department of Surgery, National and Kapodistrian University of Athens1st Surgical Clinic, Clinical Emergency County Hospital of Craiova, University of Medicine and Pharmacy of CraiovaHospital of Lithuanian University of Health Sciences, Department of Surgery, Kaunas, LithuaniaBorgo Trento Hospital, VeronaSkaraborgs Hospital, Skövde British Hospital of Buenos AiresRepublican Treatment and Diagnostic Center, BakuUmraniye Research and Training Hospital, IstanbulUniversity of Texas MD Anderson Cancer CenterUniversity Hospital 12 de OctubreVrinnevi Hospital, Linköping UniversityÖrnsköldsvik hospitalSkåne university hospital, MalmöIbrahim Said hospital on the island Aslanj, KhartoumAzienda USL of Piacenza, 29121 PiacenzaLife St. Georges Hospital, Port ElizabethHaaglanden Medisch CentrumNederlands Kanker Instituut, Antoni van Leeuwenhoek ziekenhuisHospital AlemanNational Hospital of Sri Lanka, ColomboCanberra Hospital, CanberraHospital Espírito Santo de Évora, Évora, PortugalGeneral Anticancer and Oncology Hospital of Athens Saint SavvasMaurizio Bufalini HospitalPetrovsky National Research Center of SurgeryIRCCS Policlinico San DonatoZiekenhuis Gelderse ValleiZuyderland Medisch CentrumLa Rabta Hospital, Department of Surgery B, TunisIRCCS Ospedale Galeazzi - Sant'Amrogio, University of MilanUZ BrusselNaval and Veterans Hospital of AthensNij SmellingheBernardino Ramazzini Hospital, CarpiErsta Hospital, StockholmCanisius Wihelmina ZiekenhuisBursa City HospitalAchillopouleion General Hospital of VolosGroote Schuur HospitalHippocration General HospitalUniversity Hospital of HeraklionÖrebro University Hospital, ÖrebroHospital Universitario Dr. Peset, ValenciaBarmherzige Brüder Krankenhaus GrazUmeå University Hospital, UmeåSkellefteå Hospital, SkellefteåSfanta Maria Clinical Hospital, BucharestKutahya Health Sciences UniversityMansoura Oncology Center, Surgery department, Mansoura, EgyptSlingeland ZiekenhuisIsala Ziekenhuis, Zwolle, the NetherlandsMansoura University, Gastrointestinal Surgery CenterUZ GentHospital CUF Tejo, LissabonRoyal North Shore Hospital, SydneyAcibadem Kent HospitalCancer Institute Hospital, TokyoLiverpool University HospitalsInstituto Português de Oncologia do PortoReinier de Graaf GroepShaukat Khanum Memorial Cancer Hospital and Research CentreElisabeth Tweesteden ZiekenhuisHospital Surgery Clinic of Samara State Medical UniversitySt. James's HospitalThe Prince Charles Hospital, ChermsideCentral Hospital Växjö, SwedenRyhov County Hopital, JönköpingIRCCS Saverio De Bellis, Castellana GrotteHospital Nossa Senhore da ConceicaoVästmanland's Hospital Västerås and Centre for Clinical Research Region Västmanland, UppsalaForth Valley Royal Hospital, ScotlandTor Vergata University Hospital, RomeIzmir State HospitalMetaxa Cancer Hospital, PiraeusASST Valle Olona, GallarateHospital Universitario Infanta LeonorLocal Health Unit of the Litoral Alentejano EPESengkang General HospitalDeventer ZiekenhuisZubaida Medical Center, KarachiClinical Emergency Hospital of BucharestSt. Mary Hospital, BucharestRijnstate Ziekenhuis, ArnhemHospital de Santo Espirito da Ilha TerceiraLuigi Sacco University Hospital, MilanMáxima Medisch CentrumFondazione Policlinico Universitario Agostino Gemelli IRCCS, RomeHospital Alemão Oswaldo Cruz, Sao PauloMaastricht UMCHospital Saint-Antoine, Sorbonne universiteÖstersund County HospitalLeiden University Medical CenterFederico II University HospitalSamsun University, Department of General Surgery, SamsunGelre ziekenhuizenAtatürk University Research HospitalCatharina Ziekenhuis EindhovenCampbelltown HospitalFranciscus GasthuisZaans Medical CenterJeroen Bosch ZiekenhuisAswan University HospitalPrince Rashed Bin Al-Hasan Military HospitalAl-Basheer HospitalSultan Ahmad Shah Medical CentreHospital Fundación Jimenez DiazAl-Batool HospitalInstituto Nacional de Ciencias Médicas y Nutrición Salvador ZubiránThe Royal Wolverhampton NHS TrustHospital Universitario Príncipe de AsturiasInstituo Nazionale per lo Studio e la Cura dei Tumori, Fondazione G. Pascale IRCSSQueen Elizabeth the Queen Mother Hospital, East Kent Hospital University NHS Foundation TrustSan Luigi University Hospital, University of TurinKoc University School of MedicinePalestine Medical ComplexAl-Shifaa HospitalMohamed 5th UniversityAgnelli HospitalOslo University HospitalIslamic Hospital, JordanPeter MacCallum Cancer CentreHôpital Lyon SudHospital de Tomar, Unidade Local de Saúde do Médio TejoRepublican Clinical Oncological DispensaryApollo Hospital, IndiaHospital Universitario Central de AsturiasGeneral University Hospital of ElcheIRCCS Humanitas Research HospitalHospital Universitario DonostiaKing Hussein Cancer CenterUnidade Local de Saúde da ArrábidaIRCCS Azienda Ospedaliero-Universitaria di Bologna, Pancreatic and endocrine surgery wardHospital Universitario de CanariasAOU Policlinico Umberto I, Sapienza UniversityUniversity Hospital of Gran CanariaJan Yperman HospitalHumanitas San Pio XJordan University HospitalIRCCS San Gerardo dei TintoriSan Paolo HospitalOspedale S. LeonardoAntiguo Hospital Civil de Guadalajara Fray Antonio AlcaldeHospital Universitario San AgustínRoyal Free London NHS Foundation TrustHospital de SantarémUniversity Medical Center Hamburg-EppendorfHospital Universitario de SalamancaEge University HospitalPrivate Hospital QuironAzienda Ospedaliero Universitaria Consorziale PoliclinicoHospital Universitario de La PrincessaBenghazi Medical Centreİstinye University Bahçeşehir HospitalAl-hassahissa Teaching HospitalIkazia ziekenhuisMedisch Spectrum TwenteGeneral Hospital of Piraues 'Tzaneio'Hospital Heart and BrainDijklander ziekenhuisGroene Hart ZiekenhuisMaasziekenhuis Pantein BoxmeerSpaarne GasthuisHospital of TorsbyMaasstad ZiekenhuisHippokration General Hospital, 2nd Propaedeutic Department of SurgeryAnkara University School of MedicineCeccarini HospitalBravis ziekenhuisFlevoziekenhuisMedical University of South CarolinaUMC GroningenPoliclinico Universitario Agostino GemelliTUM University Hospital, MunichHospital de Portimão, ULS AlgarveVall d'Hebron University HospitalBudapesti Uzsoki utcai KórházHaga ZiekenhuisMenoufia UniversityMartini ZiekenhuisKantonsspital WinterthurHippocration General Hospital, 1st Propaedeutic Department of SurgeryAbu Salim Accident HospitalDamascus HospitalGharyan Central HospitalHippocrates General Hospital, 5th Surgical DepartmentIppokratio General HospitalAssiut University General HospitalBox Hill hospitalLomonosov Moscow State UniversityEHS Salim ZmirliHospital Universitario Infanta CristinaTernopil Regional Oncological HospitalHospital Universitario de ToledoCHU Amiens-PicardieOspedale Santa RosaAlafia ClinicSakarya University Training and Research HospitalGood Hope HospitalCHU Benbadis, Service de Chirurgie ANorthern Hospital, EppingOdense University HospitalLaurentius Ziekenhuis RoermondUniversity of Health Sciences - Gülhane Training and Research Hospital European Institue of Oncology IRCCSSahlgrenska University HospitalUniversity Hospitals Coventry & WarwickshireZiekenhuis Groep TwenteHospital Clinic BarcelonaKasr Al Ainy Teaching HospitalsDrammen hospital