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. 2025 Jun 25.
doi: 10.1245/s10434-025-17359-w. Online ahead of print.

Consensus Guideline for the Management of Patients with Appendiceal Tumors, Part 1: Appendiceal Tumors Without Peritoneal Involvement

Elizabeth L Godfrey  1 , Forest Mahoney  2 , Varun V Bansal  1 , David G Su  1 , David N Hanna  3 , Felipe Lopez-Ramirez  4 , Ekaterina Baron  5 , Kiran K Turaga  6 , Al B Benson 3rd  7 , James Cusack  8 , Joshua H Winer  9 , Craig G Gunderson  1   10   11 , Joseph Misdraji  12 , Rupen Shah  13 , Deepa R Magge  3 , Ian Solsky  14 , Cathy Eng  15 , Oliver S Eng  16 , Ardaman Shergill  17 , John Paul Shen  18 , Michael B Foote  19 ; Peritoneal Surface Malignancies (PSM) Consortium Group
Collaborators, Affiliations

Consensus Guideline for the Management of Patients with Appendiceal Tumors, Part 1: Appendiceal Tumors Without Peritoneal Involvement

Elizabeth L Godfrey et al. Ann Surg Oncol. .

Abstract

Background: Appendiceal tumors comprise a heterogeneous group of tumors that may be localized or disseminate throughout the peritoneum. Limited high quality clinical data exist and many practices have been extrapolated from colorectal cancer without validation in appendiceal cohorts. There are many controversies regarding the treatment of appendiceal tumors, and practices vary widely between centers and care settings. A national consensus update of best management practices for appendiceal malignancies was performed to better standardize care.

Methods: The 2018 Chicago Consensus guideline was updated through a modified Delphi consensus, performed over two rounds using nationally circulated surveys. Supporting evidence was evaluated using rapid systematic reviews. Key systemic therapy concepts were summarized by content experts.

Results: Most supporting literature consists of observational studies, but high-quality studies increasingly are becoming available to drive management. Two consensus-based pathways were generated for localized appendiceal tumors, one for epithelial mucinous neoplasms and another for appendiceal adenocarcinoma. Of 138 participants responding in the first round, 133 (96%) engaged in the second round. Greater than 90% consensus was achieved for all pathway blocks. Key points include minimizing intervention invasiveness where permitted by pathologic classification and margin status, and determining which margin and pathologic findings are indications for consideration of cytoreduction with or without intraperitoneal chemotherapy. Surveillance and systemic therapy recommendations are also presented.

Conclusion: With growing but still primarily observational evidence currently dictating care, these consensus recommendations provide expert guidance in the treatment of appendiceal tumors without peritoneal involvement.

Keywords: Appendiceal malignancies; Cytoreductive surgical procedures; Guidelines; Peritoneal neoplasms; Peritoneal surface malignancies.

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Conflict of interest statement

Disclosure: Al B. Benson, III, MD6: Dr. Benson has grants and contracts with the following entities in which funds are provided directly to Northwestern University: Infinity Pharmaceuticals, Merck Sharp & Dohme Taiho Pharmaceutical, Bristol-Myers Squibb –DMC, Celgene, Rafael Pharmaceuticals, MedImmune, Xencor, Astellas Pharma – DMC, Amgen, Syncore – DMC, Tyme Inc – DMC, ITM Solucin GmbH, PANC003 – Rafael Pharmaceuticals, Inc., RM-110 – Elevar Therapeutics, Inc., STP-ST-01 - ST Pharm Co., Ltd., and Mirati Therapeutics. He has personal grant and contract relationships with Elevar Therapeutics, Inc, ITM Solucin, Janssen Merck Sharp and Dohme LLC, Pfizer, ITM Samsung Bioepsis, National Cancer Institute Lead Academic Participating Site ST Pharm CO. Ltd, The Nathan Cummings Foundation, and Xenor. He receives support for meetings and travel associated with NCCN panel meetings, ACCC meetings, and Fight Colorectal Cancer Advocacy. He participates on advisory and DSMBs for the following: BMS, Astellas, Apexigen, PrecisCA, Array (Pfizer); Novartis DMC, Amgen, Terumo, Mirati, GSK, Bayer, Aveo DMC, Gusto, Boehringer Ingelheim, Abbvie, Artemida, White Swan, Harborside Press, Patient Resources, LLC, Axis Medical Education, Envision Communications, Trialcard Incorp, Tempus Labs, Inc, Aptitude Health, Therabionic, Aptitude Health, Clarivate Analytics US LLC, Tukysa, Natera, Janssen, AIM Immuno Tech, Nuvation Bio, Xencor, Janssen, Natera, Xenor, Boston Scientific, Tukysa, and Cardiff Oncology. He participates in the following unpaid leadership or fiduciary roles: Board of Directors NCCN and NCCN Foundation, Patient Advocate Foundation (PAF), National Patient Advocate Foundation (NPAF), Scientific Advisor for Fight Colorectal Cancer. Oliver S. Eng, MD14: Dr. Eng receives speaker fees from Tempus Labs, Inc. Ardaman Shergill, MD, MSPH15: Dr. Shergill is on the advisory board for Pfizer, Guardant, and Natera. She has received travel, registration, and accommodation support for presenting at AACR from Takeda. She is also the recipient of research related funding from the following entities in which funds are provided directly to University of Chicago: Hutchison MediPharma, Merck, Verastem Oncology, Turning Point Therapeutics, Gritstone, Bolt Therapeutics, BMS, Pfizer, Astellas, Oncologie, Macogenics, Seattle Genetics, Amgen, Daiichi, Lilly, Jacobio, and Takeda. John Paul Shen, MD16: reported receiving personal fees from Nadeno Nanoscience and Engine Bioscience; receiving grants from Celsius Therapeutics and BostonGene outside the submitted work; holding a patent for small molecule GNAS inhibitors; and serving on the Medical Advisory Board for Appendix Cancer Pseudomyxoma Peritonei Research Foundation (unpaid). Other authors have no relevant financial disclosures. Ethics Approval and Consent to Participate: Not applicable. Consent for Publication: Not applicable. Generative AI and AI-assisted Technologies in the Writing Process: No AI or AI-assisted technologies were used during the drafting of this manuscript. VB used chatGPT to revise previously written content, which was then reviewed manually by EG and further revised.

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