Pembrolizumab as a first line therapy in a patient with extensive mucoepidermoid salivary gland carcinoma. A complete clinical, radiological and pathological response. A very specific case

Abstract

Abstract Background Patients with advanced salivary gland malignancies (SGCs) have few therapy options. Although results from newly published trials suggest that checkpoint inhibition may be useful in a subgroup of patients, there are no clear criteria for PD-L1 score in SGCs. Chemotherapy benefits were observed to be limited, with a dismal prognosis in unresectable and high-grade SGC. Immunotherapies have demonstrated extraordinary efficacy in a variety of cancers, including non-small cell lung cancer and malignant melanoma. Anti-PD-1 antibody pembrolizumab has been shown to have potent anti-tumor action in a number of clinical trials. Case presentation We report a unique case of advanced high grade mucoepidermoid carcinoma of the parotid salivary gland after Pembrolizumab treatment as a first line therapy. The tumor was downstaged as a result of the pembrolizumab treatment, allowing for a successful surgical excision with no facial nerve sacrifice and no major neoadjuvant treatment adverse effects, and the final specimen pathology was tumor-free. In these types of malignancies, a similar technique resulted in a complete response (CR) radiologically and pathologically has never been discussed before. Conclusions In pretreated patients with high-grade salivary gland mucoepidermoid carcinoma, pembrolizumab showed good anticancer activity and provided a clinically, radiologically, and pathological response with a viable treatment choice. More research is needed to bring Pembrolizumab to the front-line of treatment. The time and duration of medication should be compared to the time required for surgery in these investigations.