Pulmonary papillary squamous cell carcinoma: a population-based analysis of incidence, treatment, and prognosis

Background: Pulmonary papillary squamous cell carcinoma (PSCC) is a rare variant of pulmonary squamous cell carcinoma (SCC). This study aims to improve relevant understanding and demonstrate the incidence, treatment, and prognosis of pulmonary PSCC using a population-based database. Methods: The Surveillance, Epidemiology and End Results (SEER) database was used to extract data of cases diagnosed with PSCC from 1973 to 2015 and analyze the incidence, treatment, and prognosis. Results: A total of 151 pulmonary PSCC cases were identified. The incidence of pulmonary PSCC cases in 2015 was 0.009 per 100,000 persons. The tumor grade of pulmonary PSCC cases was significantly lower than that of SCC cases (P<0.001). Both cancer-specific (CSS) and overall survival (OS) of pulmonary PSCC were significantly higher than those of other pulmonary SCCs (P<0.001). The outcomes of pulmonary PSCC cases receiving surgery were significantly better than cases without surgery (P<0.001). On the contrary, patients with radiotherapy had a worsened prognosis compared with those without radiotherapy (P<0.05). As expected, the prognosis of pulmonary PSCC cases receiving surgery was significantly better than that of pulmonary PSCC cases receiving chemotherapy and radiotherapy (both P<0.05). Conclusions: Our population-based evidence shows that pulmonary PSCC, as a rare cancer, has a better prognosis compared with other pulmonary SCCs. Surgery was the only effective treatment to improve CSS and OS, while chemotherapy was ineffective and radiotherapy worsened prognosis.