Comparison Of Clinical Characteristics And Prognosis Of OCS And HGSC Based On Propensity Score Matching

Background:Ovarian Carcinosarcoma(OCS)was a rare tumor with high malignancy.At present,there are few studies on OCS at home and abroad,and there is no mature treatment mode for this disease.Existing studies have reported different conclusions on the improvement value of different treatment schemes for patients’ prognoses.At the same time,the prevalence of the disease makes it difficult to conduct prospective clinical trials to evaluate the efficacy of different treatment regimens.Previous studies have shown that OCS is an epithelial-driven tumor with sarcomatous components generated by carcinoma through Epithelial-mesenchymal transition(EMT),and no correlation between histological subtypes and poor prognosis has been found.Therefore,some researchers believe that the management of OCS can be directly referred to as the treatment of epithelial ovarian cancer.Carcinoma cell reduction combined with postoperative chemotherapy is the cornerstone of the treatment of ovarian cancer.It is the most common histological subtype in epithelial ovarian cancer.The purpose of this study was to compare the clinical features and prognostic outcomes of patients with ovarian sarcoma and high-grade serous cancer and to explore the prognostic differences between the two groups of patients after surgery combined with chemotherapy,to deepen the understanding of the disease characteristics of OCS and evaluate the value of current treatment for improving the prognostic outcome of patients with OCS.Method:The information of OCS and HGSC patients who were admitted to Qilu Hospital of Shandong University and from The Surveillance,Epidemiology,and End Results(SEER)Program of the United States of America were collected.A total of 1249 patients with OCS and 15,664 patients with HGSC were screened followed by Inclusion and exclusion criteria.Differences between variables were compared by t-test or chi-square test.Propensity score matching(PSM)was used to balance the differences in baseline between the two groups.Kaplan-Meier survival analysis was used to draw the survival curve of the two groups before and after matching.Subgroup analysis was performed by univariate COX regression in the cohort after PSM and univariate and multivariate COX regression analyses were used to find significant independent risk factors.The patients who received cytoreductive surgery combined with chemotherapy were selected from the overall patients,and the prognostic outcomes of the two groups were compared.Results:1.Comparison of clinical characteristics between the two groups before PSM matching:In the cohort before PSM matching,compared with HGSC patients,OCS patients were older at diagnosis(66±12 years vs.63±12 years.P<0.001),and a slightly higher proportion of patients were black(6.8%vs.4.7%)or unmarried(14.0%vs.12.4%),with differences in race distribution and marital status(P<0.05).Unilateral ovarian involvement was common in OCS(60.3%).and the tumor size was larger(122.56±68.80mm vs.85.68±56.84mm,p<0.001).Fewer OCS patients underwent surgery than HGSC(92.1%vs.97.3%),but OCS patients had a higher rate of no visible disease after cytoreductive surgery(12.6%vs.9.6%).Fewer OCS patients underwent lymph node surgery than HGSC patients(43.3%vs.40.0%),and more OCS patients did not have lymph node metastasis(56.7%vs.49.6%).Although 79.7%of patients had FIGO stage Ⅲ or Ⅳ at diagnosis,a higher proportion of OCS than HGSC patients had FIGO stages Ⅰ and Ⅱ across FIGO stages(29.4%vs.19.5%).Postoperative adjuvant therapy was mainly chemotherapy,but the proportion of OCS patients who received chemotherapy was lower than that of HGSC patients(72.3%vs.83.3%),while some OCS patients(4.2%)also received radiotherapy.2.Histological types of OCS carcinomatous and sarcomatous components:Twenty-one patients with OCS admitted to Qilu Hospital of Shandong University were grouped according to the histological type of cancer component(high-grade serous carcinoma,others)and the source of sarcoma component(heterologous origin,others).Univariate COX regression analysis and Kaplan-Meier survival analysis were performed.The results showed that there was no significant correlation between the histological type of cancer component or the origin of the sarcoma component and the OS of patients(P>0.05).3.Prognostic analysis of the two groups after PSM matching:Our study showed that there was no statistically significant difference in survival prognosis between OCS patients with high-grade serous carcinoma in epithelial components and OCS patients with other types.Therefore,all patients with OCS were included to compare their prognosis with those with HGSC.After PSM with 1249 patients in each group,there were no significant differences between groups in both baseline and pathologic characteristics(P>0.05,SMD<0.1).KaplanMeier survival analysis showed that the median Overall survival(OS)and median Diseasespecific survival(DSS)of OCS patients were lower than those of HGSC patients before and after matching(median OS before PSM:17 vs.43 months,median DSS:19 vs.46 months;After PSM,median OS:17 months vs.41 months,median DSS:19 months vs.47 months),and the differences were statistically significant(P<0.001).In each FIGO stage,the 5-year overall survival rate and 5-year disease-specific survival rate of OCS patients were lower than those of HGSC patients,and the survival rate gradually decreased with the increase of stage.Univariate COX regression subgroup analysis showed that patients with OCS histology type had a higher risk of all-cause death(HR:1.46,95%CI:1.33-1.59,P<0.001)and disease-specific mortality(HR:1.53,95%CI:1.39-1.69,P<0.001).There was no significant difference in the risk of death caused by OCS and HGSC in the subgroups of no surgery,pelvic exenteration,lymph node biopsy,unknown lymph node surgery,and postoperative residual lesion size≤1 cm and>1 cm(P>0.05).4.Univariate and multivariate COX regression analysis:Univariate and multivariate COX regression analysis screened out the independent risk factors for prognosis.Age>62 years,postoperative residual macroscopic lesions,lymph node metastasis or distant metastasis,and late FIGO stage were independent risk factors for reducing OS and DSS in both groups.Systematic lymph node resection and chemotherapy are independent protective factors for the prognosis of patients with OCS.For patients with HGSC,bilateral ovarian involvement and tumor diameter>170mm are also independent risk factors affecting the prognosis of patients.Surgical treatment,systematic lymph node resection,and chemotherapy can improve the prognosis of patients with HGSC.5.Comparison of the prognosis of OCS and HGSC patients after surgery combined with chemotherapy:the survival prognosis of patients can be improved by receiving tumor cytoreductive surgery without macroscopic lesions combined with chemotherapy,but the improvement of the prognosis of OCS patients is not as significant as that of HGSC patients.The 5-year overall survival and 5-year disease-specific survival of OCS patients remain lower than those of HGSC patients.However,when stratified by FIGO stage,the median OS and DSS of the two groups in FIGO stage Ⅰ/Ⅱ were similar and the difference was not statistically significant(P>0.05);However,in FIGO stage Ⅲ/Ⅳ patients,the median OS and DSS of OCS patients were still shorter,and the differences were statistically significant(P<0.05).Conclusion:1.OCS has unique clinical behavior and histopathological features,its natural course is different from that of HGSC,and its prognosis is extremely poor.2.Age,postoperative residual lesion size,lymph node metastasis,distant metastasis,FIGO stage,systematic lymph node resection,and chemotherapy are independent risk factors for OS and DSS in patients with OCS.3.Cytoreductive surgery combined with chemotherapy can make OCS patients with early FIGO achieve a prognostic outcome similar to that of HGSC patients,but the prognosis of OCS patients with advanced FIGO is worse than that of HGSC patients.