Primary squamous cell carcinoma of the pancreas: A SEER-based analysis.

Abstract

e16389 Background: Primary squamous cell carcinoma of the pancreas (PSCCP) is an exceedingly rare malignancy with a poor prognosis. Given the limited literature on PPSCC, we conducted a population-based analysis to identify patient demographics, treatment patterns, and predictors of survival. Methods: Patients with histologically confirmed PSCCP diagnosed between 2000 and 2020 were identified from the SEER database. Demographics, socioeconomic factors, tumor stage, and initial treatment modality were extracted. Overall survival (OS) was estimated by the Kaplan-Meier method. Associations with all-cause mortality were assessed using univariable and multivariable Cox proportional hazards models, adjusting for key demographic, clinical, and treatment covariates. Patients with unknown stage were excluded from the multivariate model. Statistical analyses were performed using R version 4.5.2. Results: Among 397 identified PSCCP cases, the cohort was 51.6% male, 59.7% were non-Hispanic White, 15.9% Black, and 11.6% Hispanic, with 90.4% residing in metropolitan areas. Disease characteristics showed that 49.9% of cases had distant metastasis, 26.7% had regional metastasis, and 5.5% had localized spread. Regarding treatment, 45.3% of cases received chemotherapy, 14.1% underwent surgery, and 9.8% received radiation. Median OS was 3.0 months (IQR 1.0-9.0) with an estimated one-year OS of approximately 20%. Univariable analysis showed significantly increased mortality with older age (HR = 1.55, 95%CI 1.26-1.91) and distant stage (HR = 2.64, 95% CI 1.59 to 4.36), while surgery (HR = 0.21, 95%CI 0.14-0.29) and chemotherapy (HR = 0.64, 95%CI 0.52-0.78) were associated with improved survival (all p < 0.001). Notably, median OS in those who underwent surgery was 18 months, compared to 3 months in those who did not (log-rank p < 0.001). On multivariate analysis, age ≥65 years (HR = 1.37, 95% CI 1.08-1.75, p = 0.011) and distant stage (HR = 1.83, 95% CI 1.07-3.14, p = 0.028) remained independently associated with worse survival. However, surgery (adjusted HR = 0.20, 95% CI 0.13-0.31, p < 0.001) and chemotherapy (HR = 0.44, 95% CI 0.34-0.56, p < 0.001) were independently associated with improved survival. Conclusions: PSCCP is a rare malignancy with a median OS of 3 months, frequently presenting with distant-stage disease. Advanced stage remained an independent predictor of mortality, while surgical resection was associated with a substantial survival benefit. No significant disparities in survival were observed by sex, race, or socioeconomic status. Results may be limited by the timing of diagnosis, the surgical candidacy of patients, or the small sample size. These findings emphasize the importance of early detection and multimodal therapy when feasible.