Salivary duct carcinoma (SDC) is a rare malignant tumor with a poor prognosis. Usually, operation and radiation are carried out as the standard treatments. However, no chemotherapy regimen has been established because of the rarity of this carcinoma. SDC histologically resembles invasive breast ductal carcinoma. Recently, overexpression of human epidermal growth factor receptor-2 (HER-2) has been reported in SDC also, besides breast cancer. We report a case of metastatic SDC who received long-term treatment with trastuzumab.
The patient was a 62-year-old male who presented with a left neck swelling and a feeling of sensory discomfort along the left submandibular bone. He underwent sialoadenectomy with bilateral neck dissection and postoperative radiation, followed by chemotherapy (cisplatin and docetaxel). Immunohistochemistry showed overexpression of the HER-2 protein in the tumor cells. No local recurrence has been detected, however, the patient presented with lung metastatic lesions that were increasing in size. Therefore, we started him on trastuzumab. At present, the metastatic lesions are still progressing, albeit slowly, and the patient has been taking trastuzumab for 42 months without side effects. The patient survives until date, 59 months after the initiation of therapy. A trastuzumab-based regimen is a potentially valid therapeutic option for advanced SDC.
