{"entity":{"id":"appendiceal","kind":"cancer","name":"Appendiceal cancer and pseudomyxoma peritonei","aka":["Appendix cancer","PMP","Low-grade appendiceal mucinous neoplasm (LAMN)"],"tldr":"Rare tumours of the appendix that range from slow mucin-producing growths that fill the abdomen (pseudomyxoma peritonei) to aggressive adenocarcinomas. The slow forms are treated by extensive surgery with heated chemotherapy in the abdomen; the fast ones like colon cancer.","summary":"Appendiceal neoplasms include low-grade appendiceal mucinous neoplasms (LAMN) that rupture and seed the peritoneum as pseudomyxoma peritonei (PMP), mucinous and non-mucinous adenocarcinomas, goblet cell adenocarcinoma, and neuroendocrine tumours (the most common appendix tumour, usually cured by appendicectomy). PSOGI grading (acellular mucin, low-grade, high-grade, signet ring) predicts outcome. GNAS mutations mark low-grade mucinous disease; KRAS, TP53 and SMAD4 mark higher grade.\n\nFor PMP and peritoneal disease, cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC, usually mitomycin C) at an experienced centre gives 10-year survival of ~60-70% for low-grade disease (Sugarbaker, Chua 2012). Systemic chemotherapy (FOLFOX/CAPOX) is used for high-grade and unresectable disease but a randomised trial (2024) showed no benefit in low-grade mucinous carcinoma peritonei. Iterative CRS, mucolytics (bromelain-acetylcysteine) and intraperitoneal therapies are under study. Appendiceal adenocarcinoma is otherwise managed like colorectal cancer, with right hemicolectomy and stage-based chemotherapy.","asOf":"2026-09-08","wikipedia":"https://en.wikipedia.org/wiki/Pseudomyxoma_peritonei","links":[{"label":"PSOGI consensus (Am J Surg Pathol 2016)","url":"https://doi.org/10.1097/PAS.0000000000000535"},{"label":"Appendix Cancer / PMP Research Foundation","url":"https://www.acpmp.org/"}],"tags":["gap-fill","gastrointestinal","rare"],"related":[],"cancers":[],"sections":[],"technologies":["hipec","cytotoxic-chemotherapy","ct","mri"],"targets":["kras","tp53"],"drugs":["folfox","capox","bevacizumab","mitomycin"],"companies":[],"institutions":[],"pathways":["ras-mapk"],"terms":["peritoneal-metastasis","colectomy"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"gastrointestinal","burden":"About 1-2 per 100,000 per year and rising, especially in adults under 50; most are found incidentally at appendicectomy.","subtypes":["LAMN / HAMN (low- and high-grade appendiceal mucinous neoplasm)","Pseudomyxoma peritonei (low- vs high-grade, PSOGI)","Mucinous and non-mucinous adenocarcinoma","Goblet cell adenocarcinoma","Signet ring cell carcinoma","Appendiceal neuroendocrine tumour"],"biomarkers":["PSOGI histologic grade","Peritoneal cancer index (PCI) and completeness of cytoreduction (CC score)","GNAS (low-grade), KRAS, TP53, SMAD4","CEA, CA19-9, CA-125","MSI (rare)"],"standardOfCare":[{"setting":"Localised LAMN / adenocarcinoma","approach":"Appendicectomy (LAMN without perforation) or right hemicolectomy (adenocarcinoma, goblet cell); adjuvant chemotherapy for node-positive adenocarcinoma by colorectal analogy.","refs":["folfox","capox"],"guideline":{"nccn":"Category 2A","version":"NCCN Guidelines: Colon Cancer (appendiceal section)","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}},{"setting":"Pseudomyxoma peritonei / peritoneal disease","approach":"Cytoreductive surgery with HIPEC at a peritoneal-surface-malignancy centre; repeat CRS for recurrence when feasible.","refs":["hipec"],"guideline":{"version":"PSOGI consensus (2016); Chicago Consensus (2020)"}},{"setting":"High-grade or unresectable peritoneal disease","approach":"FOLFOX/CAPOX ± bevacizumab; systemic chemotherapy has no proven benefit in low-grade disease (randomised 2024).","refs":["folfox","capox","bevacizumab"]}],"stateOfArt":["CRS-HIPEC turned PMP from a disease with no effective treatment into one with long survival for low-grade histology.","Grade, not stage, drives therapy: the 2024 randomised trial ended routine chemotherapy for low-grade mucinous carcinomatosis.","Molecular profiling (GNAS vs KRAS/TP53) is beginning to formalise the low/high grade split."],"history":[{"year":1842,"title":"Rokitansky describes a mucocele of the appendix","refs":[]},{"year":1884,"title":"Werth coins 'pseudomyxoma peritonei'","refs":[]},{"year":1995,"title":"Sugarbaker's peritonectomy procedures and HIPEC","refs":["hipec"]},{"year":2012,"title":"Multi-institutional CRS-HIPEC outcomes: 10-year survival 63% (Chua, JCO)","refs":["hipec"]},{"year":2016,"title":"PSOGI classification of appendiceal mucinous neoplasms and PMP","refs":[]},{"year":2024,"title":"Randomised trial: no benefit of systemic chemotherapy in low-grade mucinous carcinoma peritonei","refs":["folfox"]}],"pipeline":["hipec","folfox"],"openProblems":["No effective systemic therapy for high-grade or signet-ring disease.","Selection for CRS-HIPEC and management of recurrence after maximal surgery.","Rising incidence in young adults is unexplained.","Centralisation: outcomes depend heavily on centre experience."]},"route":"/cancers/appendiceal/","neighbours":{"technology":[{"id":"cea-surveillance-colorectal","kind":"technology","name":"CEA surveillance after colorectal cancer surgery","route":"/technologies/cea-surveillance-colorectal/"},{"id":"ct","kind":"technology","name":"CT (computed tomography)","route":"/technologies/ct/"},{"id":"cytotoxic-chemotherapy","kind":"technology","name":"Cytotoxic chemotherapy","route":"/technologies/cytotoxic-chemotherapy/"},{"id":"hipec","kind":"technology","name":"HIPEC / PIPAC (intraperitoneal chemotherapy)","route":"/technologies/hipec/"},{"id":"hipec-pipac-devices","kind":"technology","name":"HIPEC perfusion pumps and PIPAC nebulisers","route":"/technologies/hipec-pipac-devices/"},{"id":"mri","kind":"technology","name":"MRI","route":"/technologies/mri/"}],"target":[{"id":"kras","kind":"target","name":"KRAS","route":"/targets/kras/"},{"id":"tp53","kind":"target","name":"TP53","route":"/targets/tp53/"}],"drug":[{"id":"bevacizumab","kind":"drug","name":"Bevacizumab","route":"/drugs/bevacizumab/"},{"id":"capox","kind":"drug","name":"CAPOX (capecitabine, oxaliplatin)","route":"/drugs/capox/"},{"id":"folfox","kind":"drug","name":"FOLFOX (5-FU, leucovorin, oxaliplatin)","route":"/drugs/folfox/"},{"id":"mitomycin","kind":"drug","name":"Mitomycin C","route":"/drugs/mitomycin/"},{"id":"oxaliplatin","kind":"drug","name":"Oxaliplatin","route":"/drugs/oxaliplatin/"}],"pathway":[{"id":"ras-mapk","kind":"pathway","name":"RAS / RAF / MEK / ERK (MAPK)","route":"/pathways/ras-mapk/"}],"term":[{"id":"colectomy","kind":"term","name":"Colectomy","route":"/terms/colectomy/"},{"id":"peritoneal-metastasis","kind":"term","name":"Peritoneal metastasis","route":"/terms/peritoneal-metastasis/"},{"id":"rare-cancers","kind":"term","name":"Rare cancers","route":"/terms/rare-cancers/"}],"cancer":[{"id":"appendiceal-adenocarcinoma","kind":"cancer","name":"Appendiceal adenocarcinoma (mucinous and non-mucinous, including signet ring cell)","route":"/cancers/appendiceal-adenocarcinoma/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"goblet-cell-adenocarcinoma","kind":"cancer","name":"Goblet cell adenocarcinoma of the appendix","route":"/cancers/goblet-cell-adenocarcinoma/"},{"id":"low-grade-appendiceal-mucinous-neoplasm","kind":"cancer","name":"Low-grade appendiceal mucinous neoplasm and pseudomyxoma peritonei","route":"/cancers/low-grade-appendiceal-mucinous-neoplasm/"}],"company":[{"id":"belmont-medical-technologies","kind":"company","name":"Belmont Medical Technologies","route":"/companies/belmont-medical-technologies/"}],"trial":[{"id":"nct06399757","kind":"trial","name":"A Study to Investigate APL-5125 in Adults With Advanced Solid Tumors","route":"/trials/nct06399757/"}]}}