The extent of androgen receptor and HER2 expression allows for targeted therapy in most cases of salivary duct carcinoma: analysis of clinical and histopathological data in a tertiary care center

Marcel Mayer; Philipp Wolber; Johanna Prinz; Louis Jansen; Julia Esser; Sami Shabli; Alexander Quaas; Jens Peter Klußmann; Shachi Jenny Sharma; Lisa Nachtsheim; Christoph Arolt

doi:10.1007/s00405-024-08627-8

The extent of androgen receptor and HER2 expression allows for targeted therapy in most cases of salivary duct carcinoma: analysis of clinical and histopathological data in a tertiary care center

Eur Arch Otorhinolaryngol. 2024 Apr 8. doi: 10.1007/s00405-024-08627-8. Online ahead of print.

Authors

Marcel Mayer^{1

2}, Philipp Wolber^{3

4}, Johanna Prinz⁵, Louis Jansen^{3

4}, Julia Esser^{3

4}, Sami Shabli^{3

4}, Alexander Quaas⁶, Jens Peter Klußmann^{3

4}, Shachi Jenny Sharma^{3

4}, Lisa Nachtsheim^#^{3

4}, Christoph Arolt^#⁶

Affiliations

¹ Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, Cologne, Germany. marcel.mayer@uk-koeln.de.
² Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany. marcel.mayer@uk-koeln.de.
³ Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, Cologne, Germany.
⁴ Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany.
⁵ Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, University of Cologne, Cologne, Germany.
⁶ Institute of Pathology, Medical Faculty, University of Cologne, Cologne, Germany.

^# Contributed equally.

PMID: 38587651
DOI: 10.1007/s00405-024-08627-8

Abstract

Purpose: The incidence of salivary duct carcinoma (SDC) seems to be underestimated due to inaccurate classification. Further, the frequency of SDC patients with targeted therapy options according to current guidelines is unclear. Therefore, this study aimed at (a) describing the proportion of SDC among salivary gland carcinoma (SGC) before and after reclassification of cases initially classified as adenocarcinoma, not otherwise specified (ANOS); and (b) quantifying the frequency of SDC patients with targeted therapy options.

Methods: All patients with SDC or ANOS treated in a tertiary care center between 1996 and 2023 were identified. Histopathological diagnosis was verified for patients primarily diagnosed with SDC and reviewed for patients initially diagnosed with ANOS. Clinical data for SDC patients were retrieved from clinical charts. Immunohistochemical (IHC) androgen receptor (AR) and HER2 staining was performed.

Results: Among 46 SDC, 34 were primarily diagnosed as SDC and 12 had initially been classified as ANOS. The proportion of SDC among SGC was 12.1% and was rising when comparing the time periods 2000-2015 (7.1-11.5%) versus 2016-2023 (15.4-18.1%). Nuclear AR staining in > 70% of tumor cells was found in 56.8% and HER2 positivity (IHC 3 +) in 36.4% of cases. 70.5% of patients showed AR staining in > 70% of tumor cells and/or HER2 positivity and therefore at least one molecular target. 5-year overall and disease-free survival (DFS) were 62.8% and 41.0%. Multivariate Cox regression revealed positive resection margins (HR = 4.0, p = 0.03) as independent negative predictor for DFS.

Conclusions: The results suggest a rising SDC incidence and show that the extent of the AR and HER2 expression allows for targeted therapy in most SDC cases.

Keywords: Androgen receptor; Head and neck cancer; Human epidermal growth factor receptor 2; Immunohistochemistry; Salivary duct carcinoma; Salivary gland carcinoma; Survival; Targeted therapy.