10060-MET-5 LEPTOMENINGEAL METASTASES FROM HER2 POSITIVE SALIVARY GLAND CARCINOMATREATED WITH CRANIOSPINAL IRRADIATION FOLLOWED BY INTRATHECAL TRASTUZUMAB

Abstract

We report our experience with a case of intrathecal trastuzumab (Tmab) after craniospinal irradiation for leptomeningeal metastases (LM) of HER2-positive salivary gland carcinoma. The patient was a 46-year-old male with postoperative extensive cervical recurrence of left parotid carcinoma (salivary gland conduit carcinoma, HER2 positive) treated with intravenous Tmab and docetaxel. He was hospitalized for headache and nausea, and diagnosed as LM by MRI and CSF cytology. He received whole brain irradiation of 30Gy/10Fr and whole spinal cord irradiation of 30Gy/10Fr. Because of HER2 positive cancer, we applied to the ethics committee and started Tmab intrathecal treatment(IT) . The initial dose was 20 mg, which was administered intrathecally once every 3 weeks, and the dose was increased by 20 mg in 20 mg increments up to 60 mg while checking for post-dose side effects. The side effect was discomfort in the extremities during IT, which resolved by slowing down the administration rate. The time from diagnosis of LM to CNS deterioration was 9 months. Tmab IT may be effective in treating LM in HER2-positive salivary gland carcinoma. Further clinical studies are needed to evaluate efficacy and safety.