Durable Disease Control with Leuprorelin Monotherapy in Androgen Receptor-positive Salivary Duct Carcinoma of the Parotid: A Case Report

Abstract Salivary duct carcinoma (SDC) is a rare, aggressive salivary gland malignancy that frequently expresses the androgen receptor (AR). While this provides a rationale for androgen-deprivation therapy (ADT), durable responses are uncommon. We report a man with AR-positive, HER2-equivocal SDC of the right parotid gland (pT3N0M0) who was treated with parotidectomy and adjuvant radiotherapy. Approximately 14 months later, he developed bone-only metastatic relapse. After a partial response then early progression on carboplatin plus fluorouracil, single-agent leuprorelin was initiated. This resulted in durable disease control that was maintained for approximately 4 years. Subsequent focal bone progression was managed with local radiotherapy while continuing leuprorelin. Overall, he received over 6 years of treatment and has survived for more than 7 years from the onset of metastasis. This case demonstrates that luteinizing hormone-releasing hormone agonist monotherapy can provide durable benefit in selected AR-positive SDC, supporting routine AR testing and early consideration of ADT in bone-predominant disease.