Pulmonary sarcomatoid carcinoma: An analysis of a rare cancer from the Surveillance, Epidemiology, and End Results database

OBJECTIVES: Pulmonary sarcomatoid carcinoma (PSC) is a rare malignant neoplasm that accounts for a small percentage of non-smallcell lung carcinoma (NSCLC). At least 10% of PSCs has a spindle and/or giant cell component, which is often associated with a poor prognosis. We reviewed the Surveillance, Epidemiology, and End Results (SEER) database for the clinicopathological characteristics and surgical outcomes of PSCs. METHODS: The SEER database (1973-2013) was queried for PSC. A comparison between PSC and other NSCLC patients was performed. Cox regression for overall survival (OS) and logistic regression for node-positive predictors were performed. A propensity-matched (1:2) analysis (including age, gender, grade and stage) among surgically treated cases was done to compare OS in PSC versus other NSCLCs. RESULTS: A total of 955 899 NSCLC patients were identified; of these, 4987 patients had been diagnosed with PSC (0.52%). Men represented 60.9% of cases, with a median age of 68 years. The median size of the tumour was 5 cm and 3.5 cm in PSCs and NSCLCs, respectively (P < 0.001). PSC patients had significantly less Stage I, more high-grade tumours, advanced T stage, N+ disease and M1 disease (P < 0.001). In the PSC cohort, the most significant predictor of N+ disease on multivariate analysis was advanced T stage (P < 0.001). Predictors of OS in Stages I/II PSC on multivariate analysis were advanced age [P < 0.001, hazard ratio (HR) = 1.03], male gender (P = 0.024, HR = 1.25), carcinosarcoma (P = 0.002, HR = 1.76), grade (P = 0.033, HR = 1.81), T stage (P = 0.003, HR = 1.75), N status (P = 0.001, HR = 1.90) and surgical resection (P < 0.001, HR = 0.58). Among matched surgically resected cohorts, a poorer prognosis for OS was evident in PSCs in early stages (I/II) than in other NSCLCs (P = 0.009). CONCLUSIONS: PSC patients present with more advanced stage and with worse survival outcomes than other NSCLC patients. While surgical resection conveys a survival advantage in PSC, this group represents a population at a high risk for relapse and should be evaluated for novel adjuvant therapies.