Conversion Surgery After Administration of a TRK Inhibitor for Unresectable Parotid Gland Secretory Carcinoma.

Abstract

The NTRK fusion gene is detected in most salivary gland secretory carcinomas. While tropomyosin receptor kinase (TRK) inhibitors are used for various solid tumors with the fusion gene, there are no reports regarding TRK inhibitor use for unresectable parotid gland carcinomas that subsequently shrink and become resectable. Here, we report a case of salivary gland secretory carcinoma in which conversion surgery was performed after TRK inhibitor use. The patient was a 33-year-old man with a left parotid gland tumor. Examinations revealed a tumor invading the poststyloid compartment and ETV6-NTRK3 fusion gene expression. Entrectinib administration shrunk the tumor to a size surgically resectable with an adequate margin. The patient underwent total parotidectomy with left supraomohyoid neck dissection. Conversion surgery and TRK inhibitor use were effective against unresectable parotid gland carcinoma with the NTRK fusion gene. The case provides a reference for conversion surgery use for unresectable parotid gland carcinomas.