Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (778 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
A usually small, slow-growing neoplasm composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with moderately small vesicular nuclei, and covered by intact mucosa with a yellow cut surface. The tumor can occur anywhere in the gastrointestinal tract (and in the lungs and other sites); approximately 90% arise in the appendix. It is now established that these tumors are of neuroendocrine origin and derive from a primitive stem cell. (From Stedman, 25th ed and Holland et al., Cancer Medicine, 3d ed, p1182)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Carcinoid Tumors; Tumor, Carcinoid; Tumors, Carcinoid; Carcinoid; Carcinoids; Carcinoid, Goblet Cell; Carcinoids, Goblet Cell; Goblet Cell Carcinoid.
Where it fits in the MeSH classification
- Broader topics
- Neuroendocrine Tumors; Adenocarcinoma
- Narrower topics
- Malignant Carcinoid Syndrome
Research landscape
PubMed indexes 13,474 records tagged with the MeSH heading “Carcinoid Tumor” (counts retrieved 2026-10-29). 794 of them (5.9%) were published from 2020 onward, and the busiest period so far is through 1999 with 7,709 records.
Reviews account for 1,862 records (13.8%) and meta-analyses for 15. Randomized controlled trials number 46 (0.3%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 7,709 |
| 2000-2009 | 2,663 |
| 2010-2019 | 2,308 |
| 2020 onward | 794 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 1,862 | 13.8% |
| Meta-analyses | 15 | 0.1% |
| Randomized controlled trials | 46 | 0.3% |
Method: PubMed query "Carcinoid Tumor"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in cancer and oncology
Cancer research spans very different kinds of evidence. Laboratory studies in cell lines and animal models reveal mechanisms but often do not translate to patients. Early-phase trials mainly test safety and dosing, while phase 3 randomized trials and their meta-analyses are the usual basis for treatment conclusions. Outcomes also differ in meaning: tumour shrinkage, progression-free survival and overall survival are not interchangeable, and screening studies can be distorted by lead-time and overdiagnosis. When reading a result, check the cancer type and stage studied, the comparison treatment, and which outcome was measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Telotristat ethyl in carcinoid syndrome: safety and efficacy in the TELECAST phase 3 trial | 2018 | Randomized controlled trial Design not recorded in structured metadata | 104 | cc by PMID 29330194 · DOI · PMC5811631 |
| Carcinoid syndrome: update on the pathophysiology and treatment | 2018 | Review article Design not recorded in structured metadata | 68 | cc by PMID 30133565 · DOI · PMC6096975 |
| An introduction to the WHO 5th edition 2022 classification of testicular tumours | 2022 | Review article Design not recorded in structured metadata | 66 | cc by PMID 35502823 · DOI · PMC9544657 |
| European Society of Neuroendocrine Tumors (ENETS) 2025 guidance paper for lung and thymic carcinoids | 2026 | Research article Design not recorded in structured metadata | 11 | cc by PMID 41941890 · DOI · PMC13053111 |
Telotristat ethyl in carcinoid syndrome: safety and efficacy in the TELECAST phase 3 trial [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Telotristat ethyl, a tryptophan hydroxylase inhibitor, was efficacious and well tolerated in the phase 3 TELESTAR study in patients with carcinoid syndrome (CS) experiencing ≥4 bowel movements per day (BMs/day) while on somatostatin analogs (SSAs).
- Closing excerpt
- gov identifier: Nbib2063659).
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (198 words)
Telotristat ethyl, a tryptophan hydroxylase inhibitor, was efficacious and well tolerated in the phase 3 TELESTAR study in patients with carcinoid syndrome (CS) experiencing ≥4 bowel movements per day (BMs/day) while on somatostatin analogs (SSAs). TELECAST, a phase 3 companion study, assessed the safety and efficacy of telotristat ethyl in patients with CS (diarrhea, flushing, abdominal pain, nausea or elevated urinary 5-hydroxyindoleacetic acid (u5-HIAA)) with N = 76) were randomly assigned (1:1:1) to receive placebo or telotristat ethyl 250 mg or 500 mg 3 times per day (tid); 67 continued receiving telotristat ethyl 500 mg tid during the OLE. Through week 12, TEAEs were generally mild to moderate in severity; 5 (placebo), 1 (telotristat ethyl 250 mg) and 3 (telotristat ethyl 500 mg) patients experienced serious events, and the rate of TEAEs in the OLE was comparable. At week 12, significant reductions in u5-HIAA from baseline were observed, with Hodges-Lehmann estimators of median treatment differences from placebo of -54.0% (95% confidence limits, -85.0%, -25.1%, P P < 0.001) for telotristat ethyl 250 mg and 500 mg. These results support the safety and efficacy of telotristat ethyl when added to SSAs in patients with CS diarrhea (ClinicalTrials.gov identifier: Nbib2063659).
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29330194 · DOI · PMC5811631
Carcinoid syndrome: update on the pathophysiology and treatment [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Approximately 30-40% of patients with well-differentiated neuroendocrine tumors present with carcinoid syndrome, which is a paraneoplastic syndrome associated with the secretion of several humoral factors.
- Closing excerpt
- Given the complexity involving the origin, diagnosis and management of patients with carcinoid syndrome, we have undertaken a comprehensive review to update information about the pathophysiology, diagnostic tools and treatment sequence of this syndrome, which currently comprises a multidisciplinary approach.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (198 words)
Approximately 30-40% of patients with well-differentiated neuroendocrine tumors present with carcinoid syndrome, which is a paraneoplastic syndrome associated with the secretion of several humoral factors. Carcinoid syndrome significantly and negatively affects patients' quality of life; increases costs compared with the costs of nonfunctioning neuroendocrine tumors; and results in changes in patients' lifestyle, such as diet, work, physical activity and social life. For several decades, patients with neuroendocrine tumors and carcinoid syndrome have been treated with somatostatin analogues as the first-line treatment. While these agents provide significant relief from carcinoid syndrome symptoms, there is inevitable clinical progression, and new therapeutic interventions are needed. More than 40 substances have been identified as being potentially related to carcinoid syndrome; however, their individual contributions in triggering different carcinoid symptoms or complications, such as carcinoid heart disease, remain unclear. These substances include serotonin (5-HT), which appears to be the primary marker associated with the syndrome, as well as histamine, kallikrein, prostaglandins, and tachykinins. Given the complexity involving the origin, diagnosis and management of patients with carcinoid syndrome, we have undertaken a comprehensive review to update information about the pathophysiology, diagnostic tools and treatment sequence of this syndrome, which currently comprises a multidisciplinary approach.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 30133565 · DOI · PMC6096975
An introduction to the WHO 5th edition 2022 classification of testicular tumours [3]
Abstract reading summary — source excerpts
- Opening excerpt
- The 5th edition of the World Health Organisation Blue Book was published recently and includes a comprehensive update on testicular tumours.
- Closing excerpt
- Sertoliform cystadenoma has been removed as an entity from testicular adnexal tumours and placed with Sertoli cell tumours.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (248 words)
The 5th edition of the World Health Organisation Blue Book was published recently and includes a comprehensive update on testicular tumours. This builds upon the work of the 4th edition, retaining its structure and main nomenclature, including the use of the term 'germ cell neoplasia in situ' (GCNIS) for the pre-invasive lesion of most germ cell tumours and division from those not derived from GCNIS. While there have been important developments in understanding the molecular underpinnings of testicular cancer, this updated classification paradigm and approach remains rooted in morphology. Nomenclature changes include replacement of the term 'primitive neuroectodermal tumour' by 'embryonic neuroectodermal tumour' based on the non-specificity of the former term and to separate these tumours clearly from Ewing sarcoma. Seminoma is placed in a germinoma family of tumours emphasising relation to those tumours at other sites. Criteria for the diagnosis of 'teratoma with somatic transformation' have been modified to not include variable field size assessments. The word 'carcinoid' has been changed to 'neuroendocrine tumour', with most examples in the testis now classified as 'prepubertal type testicular neuroendocrine tumour'. For sex cord-stromal tumours, the use of mitotic counts per high-power field has been changed to per mm2 for malignancy assessments, and the new entities, 'signet ring stromal tumour' and 'myoid gonadal stromal tumour', are defined. Well-differentiated papillary mesothelial tumour has now been defined as tumour type with a favourable prognosis. Sertoliform cystadenoma has been removed as an entity from testicular adnexal tumours and placed with Sertoli cell tumours.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35502823 · DOI · PMC9544657
European Society of Neuroendocrine Tumors (ENETS) 2025 guidance paper for lung and thymic carcinoids [4]
Abstract reading summary — source excerpts
- Opening excerpt
- This ENETS guidance paper, developed by a multidisciplinary working group, provides up-to-date and practical advice on the diagnosis and management of lung and thymic carcinoids, based on recent developments and study results.
- Closing excerpt
- Each recommendation will provide a level of evidence and grade of recommendation as per the GRADE system (adapted from the Infectious Disease Society of United States Public Health Service grading system).
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (134 words)
This ENETS guidance paper, developed by a multidisciplinary working group, provides up-to-date and practical advice on the diagnosis and management of lung and thymic carcinoids, based on recent developments and study results. These recommendations aim to provide practical recommendations for the diagnosis, treatment and follow-up of these tumours, and pave the road for more standardised care for our patients expecting improved outcomes. This paper is structured on a question-answer format in order to address common dilemmas encountered in clinical practice, including controversial issues and areas of uncertainty, based on the best available evidence and expert opinion when good quality evidence is not available. Each recommendation will provide a level of evidence and grade of recommendation as per the GRADE system (adapted from the Infectious Disease Society of United States Public Health Service grading system).
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41941890 · DOI · PMC13053111
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article One hundred years after "carcinoid": epidemiology of and prognostic factors for neuroendocrine tumors in 35,825 cases in the United States [5]
- Research article Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practice for typical and atypical pulmonary carcinoids [6]
- Research article Review article: somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine (carcinoid) tumours [7]
- Research article Classification and Pathology of Lung Cancer [8]
- Research article Lung and thymic carcinoids: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up☆ [9]
- Research article Serotonin receptors and heart valve disease--it was meant 2B [10]
References
- Pavel M, Gross DJ, Benavent M, Perros P, Srirajaskanthan R, Warner RRP, et al.. Telotristat ethyl in carcinoid syndrome: safety and efficacy in the TELECAST phase 3 trial. . 2018. PMID 29330194 · DOI · PMC5811631
- Rubin de Celis Ferrari AC, Glasberg J, Riechelmann RP. Carcinoid syndrome: update on the pathophysiology and treatment. . 2018. PMID 30133565 · DOI · PMC6096975
- Berney DM, Cree I, Rao V, Moch H, Srigley JR, Tsuzuki T, et al.. An introduction to the WHO 5th edition 2022 classification of testicular tumours. . 2022. PMID 35502823 · DOI · PMC9544657
- Baudin E, Durand A, Durand A, Buikhuisen W, Capdevila J, Caplin M, et al.. European Society of Neuroendocrine Tumors (ENETS) 2025 guidance paper for lung and thymic carcinoids. . 2026. PMID 41941890 · DOI · PMC13053111
- Yao JC, Hassan M, Phan A, Dagohoy C, Leary C, Mares JE, et al.. One hundred years after "carcinoid": epidemiology of and prognostic factors for neuroendocrine tumors in 35,825 cases in the United States. J Clin Oncol. 2008. PMID 18565894 · DOI
- Caplin ME, Baudin E, Ferolla P, Filosso P, Garcia-Yuste M, Lim E, et al.. Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practice for typical and atypical pulmonary carcinoids. Ann Oncol. 2015. PMID 25646366 · DOI
- Modlin IM, Pavel M, Kidd M, Gustafsson BI. Review article: somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine (carcinoid) tumours. Aliment Pharmacol Ther. 2010. PMID 19845567 · DOI
- Zheng M. Classification and Pathology of Lung Cancer. Surg Oncol Clin N Am. 2016. PMID 27261908 · DOI
- Baudin E, Caplin M, Garcia-Carbonero R, Fazio N, Ferolla P, Filosso PL, et al.. Lung and thymic carcinoids: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up☆. Ann Oncol. 2021. PMID 33482246 · DOI
- Hutcheson JD, Setola V, Roth BL, Merryman WD. Serotonin receptors and heart valve disease--it was meant 2B. Pharmacol Ther. 2011. PMID 21440001 · DOI · PMC3179857
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
See how EvidenceLib is built. Spotted an error? Email support@evidencehelix.com.
Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.