Journal of Clinical Medicine (Aug 2022)

Occult Neck Metastases in Head and Neck Adenoid Cystic Carcinoma: A Systematic Review and Meta-Analysis

  • Jacopo Zocchi,
  • Matteo Campa,
  • Giulia Bianchi,
  • Oreste Iocca,
  • Pasquale Di Maio,
  • Gerardo Petruzzi,
  • Silvia Moretto,
  • Flaminia Campo,
  • Armando De Virgilio,
  • Vincent Vander Poorten,
  • Raul Pellini

DOI
https://doi.org/10.3390/jcm11164924
Journal volume & issue
Vol. 11, no. 16
p. 4924

Abstract

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Introduction: Adenoid cystic carcinoma (AdCC) is a rare tumor whose clinical course is burdened by local recurrence and distant dissemination. Lymph node metastasis is not believed to be common and its clinical impact is controversial. The aim of this study was to determine: (1) the prevalence of occult metastasis at diagnosis in cN0 head and neck AdCC, (2) its prognostic role, and (3) the consequent need to perform elective neck dissection (END). Material and Methods: A systematic review and meta-analyses following PRISMA guidelines was performed. PubMed, Embase, and Central databases were questioned up to July 2021 to identify studies reporting on the prevalence of occult neck metastases in head and neck AdCC. A single-arm meta-analysis was then performed to determine the pooled prevalence of occult lymph node metastases among the retained studies. Results: Of the initial 6317 studies identified, 16 fulfilled the inclusion criteria, and they were included in the meta-analysis. Of a population of 7534 patients, 2530 cN0 patients were treated with END, which revealed 290/2530 cases of occult metastases (pN+/cN0). Meta-analysis of the results of END in the 16 studies estimated an overall prevalence of occult metastases at diagnosis of 17%. No further subgroup analysis was possible to identify factors influencing lymph node involvement and the prognostic role of END. Conclusions: Taking 20% as an historically proposed cut off, a 17% prevalence of occult metastases represents a borderline percentage to get a definitive conclusion about the indication to END for head and neck AdCC. A more advanced UICC stage, an oropharyngeal minor salivary glands origin, and a high-grade transformation are factors to be considered in a comprehensive patient’s tailored therapeutic strategy. Multicenter prospective studies are the key to finding stronger recommendations on this topic.

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