| Objective:To analyze the demographic,clinical,and pathological factors of patients with pancreatic squamous cell carcinoma(PSCC),and to explore the factors affecting the prognosis and overall survival(OS)of PSCC patients from the Surveillance,Epidemiology,and End Results(SEER)database.We also aimed to construct a nomogram as a prediction tool for PSCC outcomes and analyze the potential factors that may help to select the patients who may benefit from chemotherapy in PSCC.Methods:Data of 135 patients with PSCC and 41940 patients with pancreatic adenocarcinoma(PAC)were extracted from the SEER database diagnosed between 2000 and 2019.Differences in patient characteristics between PSCC and PAC groups were examined using Fisher’s exact test and chi-square.135 PSCC patients included in this study were then randomly split into a training set(n=95)and another validation set(n=40)at a ratio of 7:3.Univariate and multivariate Cox regression were applied to identify independent prognostic factors in the training group.A nomogram as a prediction tool for PSCC outcomes was conducted,which was assessed by concordance index(C-index),ROC curve,and calibration curve.The patients were grouped depending on whether to perform chemotherapy,and chisquare and Fisher’s exact test were used for the difference analysis of characteristics between two arms.After propensity score matching(PSM)which was applied to control the baseline differences,Kaplan-Meier-Survival curve was used to report the OS and a subgroup analysis was performed to discover which subgroup of covariates could benefit from chemotherapy.The fundamental data analysis was conducted by R(Version 4.2.2).Two-tailed p values less than 0.05 were believed to be statistically significant.Results:(1)PSCC was prone to the elderly.Caucasian population,with an equal ratio of male to female.PSCC exhibited a predilection to occur in the head of the pancreas with poor histological grade.Compared with PAC,PSCC had a higher incidence among black and Asian populations with worse histological grading,and more likely to develop distant metastasis,especially liver metastasis.(2)In the training set,univariate Cox regression analysis showed that primary tumor site,histological grade,tumor M stage,AJCC stage,liver metastasis,chemotherapy and surgery were significantly associated with OS(P<0.05).Multivariate Cox regression analysis further revealed that distant metastasis,chemotherapy and surgery were the independent prognostic factors for PSCC.(3)A nomogram was conducted based on the above factors.The C-index of the training set was 0.751(95%CI:0.733-0.769),and the areas under the curve(AUC)of the nomogram at 3 months,half a year,and 1 year was 0.879,0.838,and 0.847 respectively;The C-index of the validation set was 0.748(95CI%:0.732-0.764)and the AUC at 3 months,half a year,and 1 year were 0.823,0.764,and 0.897 respectively.The calibration curves for both the training and validation sets are close to the 45°slash.The ROC curve and calibration curve of the two groups showed great predictive ability.(4)Chemotherapy significantly improved median OS compared with the nonchemotherapy arm(5 versus 1 months;HR:0.64,95CI:0.47-0.87,P=0.02).Subgroup analysis showed that patients with age ≥60 years,white race,poor differentiation,stage Ⅳand cancers in the pancreatic body and tail could significantly benefit from chemotherapy(P<0.05).Conclusions:(1)PSCC was more likely to occur in the elderly,Caucasian,and head of the pancreas,with a high degree of malignancy and a high rate of distant metastasis,especially liver metastasis.(2)Distant metastasis,chemotherapy and surgery were independent prognostic factors for PSCC.(3)Among the patients with PSCC,the median OS of the chemotherapy group was significantly higher than that of the non-chemotherapy group.Patients with≥ 60 years old,white race,primary tumors in pancreatic body and tail,poorly differentiated tumors,and stage Ⅳ tumors can significantly benefit from chemotherapy. |
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