INTRODUCTION: Neuroendocrine neoplasms (NEN) of the appendix are often incidentally discovered after appendectomy. Appropriate management is debated. The purpose was to characterize a cohort of 335 appendix NEN and evaluate the risk of recurrence.

METHODS: Retrospective collection of data from 335 patients referred to the Neuroendocrine Tumor Center at Rigshospitalet 2000-2019. Appendix goblet cell carcinoids and mixed neuroendocrine non-neuroendocrine neoplasms were excluded. Patients were followed until December 31st, 2019. No patients were lost to follow-up.

RESULTS: Sixty-three percent of the patients were female. The median (range) age at diagnosis was 34 (9-92) years. Median follow-up was 66 (1-250) months. Median tumor size was 7 (1-45) mm with 10 (3%) tumors >20 mm. In 18 specimens (5%) resection margins were positive. Mesoappendiceal invasion was found in 113 (35%). Sixty-three (19%) patients underwent right-sided completion hemicolectomy (RHC) after appendectomy according to ENETS guidelines. Among these, 11 (17%) had lymph node metastases in the resected tissue. Further, one patient who underwent initial RHC due to colonic adenocarcinoma had lymph node metastases. All lymph node metastases were detected in patients with serotonin positive tumors. No patients with glucagon positive tumors (n = 85) had lymph node metastases. Mesoappendiceal invasion >3 mm and positive resection margins were associated with presence of lymph node metastases. No recurrences were recorded.

CONCLUSION: Following ENETS guidelines may lead to overtreatment of patients with respect to completion RHC. The risk of over- and undertreatment needs to be further evaluated.

Original languageEnglish
JournalEuropean journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology
Issue number6
Pages (from-to)1357-1363
Number of pages7
Publication statusPublished - Jun 2021


  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Appendectomy
  • Appendiceal Neoplasms/metabolism
  • Child
  • Chromogranin A/metabolism
  • Colectomy
  • Colon, Ascending/surgery
  • Denmark
  • Female
  • Follow-Up Studies
  • Glucagon/metabolism
  • Humans
  • Lymph Nodes/pathology
  • Lymphatic Metastasis
  • Male
  • Margins of Excision
  • Medical Overuse
  • Middle Aged
  • Neoplasm Invasiveness
  • Neoplasm Recurrence, Local/pathology
  • Neuroendocrine Tumors/metabolism
  • Patient Selection
  • Practice Guidelines as Topic
  • Retrospective Studies
  • Serotonin/metabolism
  • Tumor Burden
  • Young Adult


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