Survival Comparison Of Different Histological Subtypes Of Oropharyngeal Squamous Cell Carcinoma:A Propensity Score Matching Analysis

Objective: The aim of this study was to compare the survival differences between patients with oropharyngeal keratinising squamous cell carcinoma(KSCC),nonkeratinising squamous cell carcinoma(NKSCC),basaloid squamous cell carcinoma(BSCC)and papillary squamous cell carcinoma(PSCC)by using the Surveillance,Epidemiology,and End Results(SEER)database.Methods: The clinical information was downloaded from the SEER database on patients diagnosed with oropharyngeal squamous cell carcinoma(OPSCC)between2004 and 2015 years(including information on age,gender,race,T-stage,N-stage,Mstage,surgery and radiotherapy and chemotherapy;the outcome was cancer-specific survival(CSS)).To account for confounding factors,we implemented propensity score matching(PSM)using R 4.1.2 software to match KSCC to NKSCC,KSCC to BSCC and NKSCC to BSCC each on a 1:1 ratio(due to the small sample size of PSCC,it was not matched to other subtypes.Kaplan-Meier(KM)analysis and log-rank test were used to compare the survival differences between patients with different subtypes before and after matching,and COX regression analysis was used to determine whether histological subtype was an independent factor in the prognostic assessment of OPSCC.Results: A total of 6542 patients who met the criteria were included in the study,including KSCC: 2328,NKSCC: 2809,BSCC: 1238 and PSCC: 167.All subtypes of OPSCC were mainly concentrated in the age group of 50-69 years,with a much higher proportion of males than females.A number of variables differed between each of the KSCC,NKSCC,and BSCC subtypes before matching(P < 0.05).The survival comparison of the different subtypes of oropharyngeal cancer before PSM were as follows: 5-year CSS for KSCC,NKSCC,BSCC and PSCC were: 0.627,0.812,0.789 and 0.875 respectively.The results of KM analysis and log-rank showed that 5-year CSS for PSCC subtypes were greater than for KSCC,NKSCC,and BSCC(P < 0.001,P = 0.042,and P = 0.013),both NKSCC and BSCC had higher 5-year CSS than KSCC(P < 0.001,P < 0.001);whereas there was no statistical difference between BSCC and NKSCC(P = 0.190).The 10-year specific survival rates for KSCC,NKSCC,BSCC and PSCC were: 0.557,0.761,0.711 and 0.744,respectively,with PSCC patients still having better survival rates than KSCC(P < 0.001),but no statistical difference compared to BSCC and NKSCC(P = 0.058 and P = 0.290).And both NKSCC and BSCC had greater 10-year specific survival rates than KSCC(P < 0.001 and P < 0.001),whereas there was no statistically significant difference between BSCC and NKSCC(P= 0.062).After PSM,the baseline characteristics of the subtypes were more balanced between the three cohorts and we compared the differences in CSS between patients in the three new cohorts.The results showed that the CSS of KSCC patients were lower than those of NKSCC and BSCC(P < 0.001),and in addition,the 5-year and 10-year CSS of KSCC subtypes in the corresponding matched cohort were lower than those of NKSCC and BSCC(P < 0.001);However,unlike before PSM matching,the 5-year,10-year and long-term specific survival rates were higher for NKSCC than for BSCC after PSM and were statistically different(P < 0.001).In addition,we included variables that were statistically significant after univariate COX regression analysis in the multifactor COX regression analysis,which showed that age,race,T-stage,N-stage,M-stage,surgery,radiotherapy and histological subtype were all independent prognostic factors for oropharyngeal cancer-specific survival(P < 0.05),and the results of univariate and multifactor COX analyses across the matched cohorts also showed that histological subtype was an independent factor in the prognostic assessment of oropharyngeal cancer(P < 0.05).Conclusion:(1)Histological subtypes are independent risk factors in the prognostic assessment of oropharyngeal cancer and in our clinical work we should not only focus on HPV and p16 testing,we should equally focus on the prognostic impact of histological subtypes.(2)The survival rates of different histological subtypes of oropharyngeal cancer vary to a certain extent.When dealing with patients of different subtypes,it is important to consider all indicators,actively assess them,be alert to the possibility of poor prognosis and formulate individualised interventions and treatment plans according to the prognosis of different subtypes,so as to effectively improve the long-term survival rate of patients.