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Scientific Oral Presentation

Otology/Neurotology

Adenoid Cystic Carcinoma of the External Auditory Canal Staging and Management: A Systematic Review

Saturday, October 17, 2026
3:06 PM - 3:12 PM PT
Location: 515B

    Presenting Author(s)

  • PE

    Peter Eckard, MD

    Resident
    University of Arkansas for Medical Sciences
    Little Rock, Arkansas, United States

    • Co-Author(s)

  • MV

    Mukta P. Vibhute, BS

    Clinical Research Fellow
    University of Arkansas for Medical Sciences
    Jacksonville, FL, United States

  • SV

    Stetson Van Matre, n/a

    Medical Student
    University of Arkansas for Medical Sciences, United States

  • MB

    Margaret Batson, n/a

    Medical Student
    University of Arkansas for Medical Sciences, United States

  • AB

    Alaina D. Baggett, BS

    Medical Student
    UAMS
    Little Rock, Arkansas, United States

    • Senior Author(s)

  • Robert A. Saadi, MD

    Otology and Neurotology Physician
    University of Arkansas for Medical Sciences
    Little Rock, AR, United States

Disclosure(s):
Mukta P. Vibhute, BS:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Introduction: Adenoid cystic carcinoma (ACC) is the second most common malignancy of the external auditory canal (EAC) and temporal bone. The modified Pittsburgh staging system (mPSS) is the most widely used for temporal bone malignancies but was based on squamous cell carcinoma (SCC). This study aims to systematically review reported outcomes of EAC ACC to evaluate accuracy of the current staging system.

Methods: Medline, EmBase, and Web of Science were queried for all English-language studies reporting tumor characteristics and patient outcomes from database inception to 2025 on ACC of the EAC, middle ear, or temporal bone in accordance with PRISMA guidelines. Patient demographics, TNM staging, tumor biology, high risk tumor characteristics, treatments, and patient outcomes data were compared using univariate and multivariate regression analysis. Disease free survival (DFS) and overall survival were then compared to predicted prognosis based on mPSS.

Results: Of the 270 identified abstracts, 199 underwent full text review resulting in 103 included studies comprising 391 patients. Patients were a mean age of 56 (range 12-85) and 58% female. ACC has a better 5-year overall survival compared to SCC for both low stage disease (I-II), 78% vs 67%, and high stage (III-IV), 50% vs 30%. However, 10-year DFS is worse for ACC due to late local recurrence in both low stage (40% vs 62%) and high stage (18% vs 26%). In contrast to SCC, perineural invasion and surgical margin status are key prognostic indicators as metastatic spread is more often hematogenous with late regional and distal metastases. Additionally, in limited data sets, up to 30% of patients with stage I ACC have no clinical parotid involvement but do have microscopic involvement and improved 3- and 5-year survival with superficial parotidectomy at time of initial resection.

Conclusions: ACC of the EAC is staged based on the mPSS. However, ACC has different biological characteristics affecting prognosis. Due to differences in tumor biology, overall survival based on stage, and rates of DFS, a modified staging system for ACC may better predicts prognosis and improve treatment guidance.