Significant benefits of pembrolizumab in treating refractory advanced pulmonary sarcomatoid carcinoma: A case report.

Background: Pulmonary sarcomatoid carcinoma (PSC), a rare subtype of non-small cell lung cancer (NSCLC), is poorly differentiated and highly aggressive. Treatment is limited, and the prognosis is poor. Pembrolizumab is an anti-programmed death (PD)-1 antibody with good efficacy in NSCLC. Recent studies have demonstrated that PD-ligand 1 (PD-L1) overexpression is common in PSCs, which suggests that anti-PD-L1 treatment is an ideal option. However, the response to pembrolizumab in PSC has not been studied.

Case Summary: We present a PSC case with PD-L1 overexpression that significantly benefited from pembrolizumab. A 73-year-old Chinese male was detected with a right lung lesion. Pathological analysis of the right upper lobectomy confirmed PSC. The PD-L1 test revealed overexpression (TPS: 90%). Multiple metastases occurred 1 mo after surgery, representing stage IV PSC. Neither first-line chemotherapy nor second-line antiangiogenic agents showed any benefit. Radiotherapy (1200 cGy) was administered to relieve chest wall pain. The patient received the PD-1 inhibitor pembrolizumab (100 mg) as third-line therapy; however, because of fever and severe infection, he refused to receive immunotherapy any longer. Thus, only one dose of pembrolizumab was administered. Deep sustained remission of most of the metastases was achieved except for lesions in the right adrenal gland, which first shrank and then progressed. The patient died because of disease progression in the right adrenal gland. He achieved a progression-free survival time of 8 mo and an overall survival time of 9 mo with third-line pembrolizumab.

Conclusion: Our findings highlight and offer direct evidence of the efficacy of pembrolizumab in PD-L1-overexpressing PSCs. Combined radiotherapy and immunotherapy may enhance treatment efficacy.