Spindle cell carcinoma: the general demographics, basic clinico-pathologic characteristics, treatment, outcome and prognostic factors.

Background: Owing to the rarity, the general demographics, basic clinicopathologic features, management, outcome and prognostic factors of spindle cell carcinoma (SpCC) were unexplored. Methods: A SEER analysis was performed with 2336 cases (1973- 2016). Results: A peak incidence occurred at 70 similar to 80 years without any gender predominance and 83.13% occurred in white people. The respiratory system was mostly affected tumor site (35%). Significant overall survival (OS) and disease specific survival (DSS) were found differentiated in gender, age, marital status, primary tumor location, AJCC stage, T stage, N stage, M stage, pathologic grade and treatment modality. In the multivariate Cox model, the age > 69 years (Hazard ratio [HR] = 1.427 for OS, P = 0.01 and HR = 1.491 for DSS, P = 0.003; Reference [Ref] age = 69 years), tumor location in respiratory system (HR = 1.550 for OS, P = 0.041 and HR = 1.561 for DSS, P = 0.04; Ref: digestive system), N2 stage (HR = 1.962 for OS, P = 0.006 and HR = 1.982 for DSS, P = 0.004; Ref: N0 stage) and AJCC stage IV (HR = 4.601 for OS, P = 0.000 and HR = 5.107 for DSS, P = 0.000; Ref: stage I) were independently associated with worse OS and DSS. Conclusions: SpCC mostly occurred in white people at 70 similar to 80 years old without predominance in any gender. The respiratory system was mostly affected site. The patient's age, primary tumor location, AJCC stage were independent prognostic indicators for both DSS and OS of SpCC.