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

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.

Preclinical 3D-model supports an invisibility cloak for adenoid cystic carcinoma

“…Similarly, cytotoxic immune cells in ACC are less activated compared to MEC. The observation is concordant with previous findings supporting mucoepidermoid carcinoma being more responsive to immunotherapy compared to adenoid cystic carcinoma 14 .…”

“…The advent of immune check point inhibitors triggered clinical trials using immunotherapy to reduce the progression of salivary gland cancers. Pembrolizumab which is a PD-1 inhibitor has shown promising clinical results in case of mucoepidermoid carcinoma 14 . Whereas pembrolizumab is still not FDA approved for the treatment of adenoid cystic carcinoma due to lack of PD-1 expression 15 .…”

Establishment of Mucoepidermoid Carcinoma Cell Lines from Surgical and Recurrence Biopsy Specimens

“…However, despite a high cumulative positive score, the patient in this study did not respond to pembrolizumab (CPS: 35–45). Although the association of tumor mutation burden (TMB) with treatment effectiveness for ICIs in MEC is unknown, the KEYNOTE-158 trials report that a subpopulation of 791 patients, including 82 salivary tumors with high-TMB (TMB > 10mut/Mb), showed a higher overall response rate than low-TMB cases [ 33 ]. TMB of the patient upon recurrence was 4.6 mut/Mb (see Supplementary Material ), which is relatively low.…”

PD-1 and PD-L1 expression in rare lung tumors

“…In a recent case report successful treatment with low-dose radiotherapy combined with immunotherapy was described in a patient with metastatic submandibular salivary gland ACC, however, no such data have been reported in lung ACC so far [ 17 ]. Farhat et al reported a case of advanced high-grade MEC of the parotid salivary gland after pembrolizumab treatment as a first line therapy [ 18 ]. The tumor was downstaged as a result of the immunotherapy, allowing for surgical excision.…”