Multivariate survival analysis and prevalence disparities in spindle cell carcinoma: A SEERStat-based retrospective study.

e21569 Background: Spindle cell carcinoma (SpCC) is a rare and aggressive variant of squamous cell carcinoma. It is often a biphasic tumor with both epithelial and mesenchymal components. It is characterized by the presence of elongated “spindle-shaped” cells. The purpose of this study is to determine the racial and gender disparities and survival trends in patients with spindle cell carcinoma. Methods: Total 2661 cases of SpCC were collected from SEER Plus Database, 17 Registries, Nov 2024 Sub (2000-2022), using the ICD Code 8032/3. A multivariate Cox proportional hazards regression model was used to examine the effects of independent variables including age [continuous variable], sex [reference = males], race [ref = Caucasians], year of diagnosis [continuous variable], stage [ref = localized], median household income inflation adjusted to 2023 [ref = < 100K], and treatment including surgery, chemotherapy (CTX), XRT [ref = no Tx utilized, respectively] on the survival. Dependent variables were survival (months) and an event (1 = death, 0 = censored). All analysis was conducted using GraphPad Prism 10.6.1. Results: Of the dataset, 51.8% were females. Racial distribution was: 73% Caucasians and 27% non-Caucasians races. The median age of diagnosis was 71 years. The overall median of survival (MoS) was 10 months, with a 1-year OS of 46.2% (CI 95%, 44.3%-48.1%) and 5-year OS of 26.9% (CI 95%, 25.2%-28.7%) The overall Cox proportional hazards model for multivariate analysis was statistically significant (p < 0.05). The results of the model are shown in Table 1. Conclusions: Our analysis revealed that for every 1-year increase in age, the hazard of death increased by 2.8%. Moreover, the female gender had 18% decreased risk of death compared to males. Regional spread was associated with 1.96-fold while distant stage with 3.5-fold increased risk of death compared to localized disease. Use of surgery was associated with 41% lower risk, CTX with 21% lower risk, and XRT with 13% reduced risk of death compared to no surgery, no CTX or no XRT, respectively. Higher income [ > 100K] showed 11% decline in hazard of death compared to income less than 100K. No significant association was found between race and income with survival. Further analysis highlighting the use of targeted therapy for SpCC is warranted. Variables Hazard Ratio (HR) 95% CI P value Age 1.028 1.025 - 1.032 <0.0001* Gender[female] 0.8239 0.755 - 0.898 <0.0001* YOD 0.99 0.986 - 1.001 0.0709 Race[non-Caucasians] 0.997 0.899 - 1.104 0.9529 Stage[regional] 1.957 1.726 - 2.222 <0.0001* Stage[distant] 3.51 3.034 – 4.064 <0.0001* Surgery[yes] 0.5913 0.534 – 0.6552 <0.0001* Chemotherapy[yes] 0.7944 0.7138 – 0.883 <0.0001* XRT[yes] 0.87 0.79 – 0.957 0.0040* Income[>100K] 0.8947 0.8021 – 0.9957 0.0413* *statistically significant.