[Clinical characteristics and prognosis analysis of pulmonary sarcomatoid carcinoma]

Objective: To summarize the clinical characteristics, treatment, and outcomes of patients with pulmonary sarcomatoid carcinoma (PSC) in order to improve clinicians' understanding of this disease. Methods: The clinical data of patients diagnosed with PSC in our hospital from January 1, 2015 to November 30, 2023 were retrospectively analyzed. According to whether radical resection was performed, the patients were divided into resectable group and unresectable group. The characteristics and treatments of PSC in different groups were compared. The survival curves were drawn by Kaplan-Meier method to compare the prognosis of different groups of patients. Results: A total of 43 PSC patients were included, including 32 males, with an average age of (62.79±9.59) years, and 31 smokers. Peripheral-type tumors were more common, with imaging showing predominantly solid soft tissue masses, and the maximum diameter of the tumor was more than 5 cm in 14 patients. Among the 23 patients who underwent NGS gene testing, the KRAS mutation rate was 43.5%, the TP53 mutation rate was 30.4%, and the MET mutation rate was 8.7%, all of which were MET-14 exon skipping mutations. PD-L1 expression was detected in 13 patients, 10 of whom showed high expression. The median overall survival (mOS) of the 43 patients with PSC was 24.6 months (13.0-52.7 months). Among them, 22 patients underwent radical lobectomy plus mediastinal lymph node dissection, 13 patients had postoperative recurrence, and 7 patients died during follow-up. The median disease-free survival (mDFS) was 12.3 months, the mOS was not achieved and the 1-year OS rate was 77.3 %. Twenty-one patients had unresectable locally advanced or advanced stage, and 15 patients died. The mDFS was 2.5 months, the mOS was 6.2 months, and the 1-year OS rate was 42.9 %. Seventeen patients received immunotherapy, and 1 patient received targeted therapy with the MET inhibitor glumetinib. Conclusions: PSC has a higher incidence in the elderly, smokers, and males, is highly malignant and has a poor prognosis. Based on its molecular biological characteristics, PD-L1 expression and tumor molecular detection can be performed to guide treatment options.