{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T13:47:52Z","timestamp":1782827272337,"version":"3.54.5"},"reference-count":44,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"content-version":"unspecified","delay-in-days":29,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,6,10]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Cancer recurrence is a pivotal outcome after treatment with curative intent for colon cancer patients, as it is related to worse survival, the subsequent need for further treatment and the associated use of healthcare resources. However, at present there is no consensus regarding the definition of locoregional recurrence of colon cancer. This contributes to variability in reporting outcomes and clinical management, limiting comparability across registries and clinical studies. This study aims to establish a consensus definition of locoregional recurrence using the Delphi method.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods and analysis<\/jats:title>\n                    <jats:p>We will conduct a worldwide Delphi consensus study among international experts involved in the treatment of colon cancer and recurrence (surgeons, medical oncologists, radiologists and pathologists). Conceptual elements of the survey were identified through literature exploration and concern: (i) anatomical locations, (ii) diagnostic criteria, (iii) resection margins and (iv) disease-free interval. Participants will be asked to rate their agreement on statements regarding the definition of locoregional recurrence of colon cancer. After the first round, we will analyse the data to determine which items have reached consensus for inclusion\/exclusion and develop a second survey including items that did not reach consensus and any new items suggested by participants.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Ethics and dissemination<\/jats:title>\n                    <jats:p>The Dutch Medical Research Involving Human Subjects Act (WMO) does not apply to this study, as it does not involve patient participation. Participation is restricted to clinical health professionals. Results will be disseminated via communication to relevant societies in this field, presentations on (inter)national meetings and peer-reviewed publication.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2026-118765","type":"journal-article","created":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T13:21:18Z","timestamp":1782825678000},"page":"e118765","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Consensus on the definition of locoregional recurrence of colon cancer: protocol for an international Delphi study"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9083-2550","authenticated-orcid":false,"given":"Eva","family":"Rademaker","sequence":"first","affiliation":[{"name":"Department of Surgery, Isala Zwolle, Zwolle, Netherlands"},{"name":"Department of Surgical Oncology and Gastrointestinal Surgery, Erasmus MC Cancer Center, Rotterdam, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne E","family":"Petersen","sequence":"additional","affiliation":[{"name":"Department of Paediatric Surgery, Emma Children\u2019s Hospital, University of Amsterdam, Amsterdam University Medical Centres, Amsterdam, Netherlands"},{"name":"Amsterdam Gastroenterology Endocrinology Metabolism Institute, Amsterdam University Medical Centres, Amsterdam, Netherlands"},{"name":"Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eva","family":"Angenete","sequence":"additional","affiliation":[{"name":"Department of Surgery, SSORG-Scandinavian Surgical Outcomes Research Group, Institute of Clinical Sciences, University of Gothenburg Sahlgrenska Academy, Gothenburg, Sweden"},{"name":"Department of Surgery, Region V\u00e4stra G\u00f6taland, Sahlgrenska Universitetssjukhuset, Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alvaro","family":"Arjona-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Unit of Surgical Oncology, Reina Sofia University Hospital, C\u00f3rdoba, Spain"},{"name":"GE09 Research in Peritoneal and Retroperitoneal Oncologic Surgery Group, Maimonides Biomedical Research Institute of Cordoba, C\u00f3rdoba, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Benz","sequence":"additional","affiliation":[{"name":"Klinikum Sindelfingen-Boblingen Kliniken Sindelfingen, Sindelfingen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Claus A","family":"Bertelsen","sequence":"additional","affiliation":[{"name":"Department of Surgery, Copenhagen University Hospital, Hiller\u00f8d, North Zealand, Denmark"},{"name":"Department of Clinical Medicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johanne G","family":"Bloemen","sequence":"additional","affiliation":[{"name":"Department of Surgery, Catharina Hospital, Eindhoven, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7692-4419","authenticated-orcid":false,"given":"Wim","family":"Ceelen","sequence":"additional","affiliation":[{"name":"Department of GI Surgery, Cancer Research Institute Ghent (CRIG), University Hospital Ghent, Ghent, Belgium"},{"name":"Department of Human Structure and Repair, Ghent University, Ghent, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esther C J","family":"Consten","sequence":"additional","affiliation":[{"name":"Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands"},{"name":"Department of Surgery, Meander Medical Centre, Amersfoort, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Deena","family":"Harji","sequence":"additional","affiliation":[{"name":"Department of Colorectal Surgery, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ignace H J T","family":"de Hingh","sequence":"additional","affiliation":[{"name":"Department of Surgery, Catharina Hospital, Eindhoven, Netherlands"},{"name":"Department of Research and Development, Netherlands Comprehensive Cancer Organization, Eindhoven, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivier","family":"Glehen","sequence":"additional","affiliation":[{"name":"Department of Surgical Oncology, Centre Hospitalier Lyon Sud, Pierre-B\u00e9nite, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ben","family":"Griffiths","sequence":"additional","affiliation":[{"name":"Department of Colorectal Surgery, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helene","family":"Perregaard","sequence":"additional","affiliation":[{"name":"Department of Surgery, Copenhagen University Hospital, Hiller\u00f8d, North Zealand, Denmark"},{"name":"Department of Clinical Medicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeanine M L","family":"Roodhart","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, University Medical Centre Utrecht, Utrecht, Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0974-6373","authenticated-orcid":false,"given":"Martin","family":"Ruteg\u00e5rd","sequence":"additional","affiliation":[{"name":"Department of Surgery, SSORG-Scandinavian Surgical Outcomes Research Group, Institute of Clinical Sciences, University of Gothenburg 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