Evaluation Of The Prognostic Value Of Systematic Lymphadenectomy For Low-Grade Serous Ovarian Cancer

Objective:Low-grade serous ovarian cancer(LGSOC)is a rare ovarian malignancy,and its clinical decision-making is mainly based on retrospective studies and subgroup analyses of ovarian cancer clinical trials.For newly treated LGSOC patients,primary maximal cytoreductive surgery is the cornerstone of clinical treatment.However,the prognostic value of lymphadenectomy in LGSOC patients remains uncertain.Therefore,we conducted a national multicenter study to evaluate the effect of systematic lymphadenectomy for the clinical prognosis of patients with LGSOC,in order to provide a reference for the selection of clinical surgical methods for patients with LGSOC.Materials and methods:The clinical data of 155 patients with LGSOC during 2011-2020 between 2011 and 2020 were collected from 4 medical units in China.The patients were divided into groups according to whether the systematic retroperitoneal lymph nodes were dissected during the operation.The differences between the patient groups were analyzed by the chi-square test.The propensity score matching(PSM)algorithm was used to balance the basic characteristics of the lymphadenectomy and non-lymphadenectomy groups.Kaplan-Meier analysis was used to evaluate the effect of lymphadenectomy for the clinical prognosis of LGSOC patients,and univariate and multivariate COX proportional hazards regression analysis was used to explore the protection and risk factors associated with clinical prognosis.Finally,subgroup analysis stratified by pathological stage was performed to explore the prognostic value of lymphadenectomy in patients with FIGO(International Federation of Gynecology and Obstetrics)stage Ⅰ and Ⅱ,and patients with stage Ⅲ and Ⅳ.Results:A total of 155 LGSOC patients were included in this study.The median age of onset was 47 years(21-79),and 98(63.2%)patients were not yet postmenopausal.There were 52 patients(33.5%)in stage Ⅰ,12(7.7%)in stage Ⅱ,83(53.5%)in stageⅢ,and 8(5.2%)in stage Ⅳ.One hundred and ten patients underwent pelvic and/or para-aortic lymph node resection,of which 30(27.3%)patients had lymph node metastasis.Of the 155 patients,60(38.7%)patients in the early stage underwent staging surgery with removal of all visible lesions,and 54(34.8%)patients in the advanced stage underwent satisfactory cytoreductive surgery(largest macroscopic lesion diameter≤1 cm).A total of 54 patients(34.8%)relapsed and 27(17.4%)died during the follow-up period.Grouping according to whether lymphadenectomy is performed or not,the chi-square test shows that the two groups of data have significant statistical differences in age(p=0.024),FIGO staging(p=0.018),carbohydrate antigen 125(CA-125)levels(p=0.014),cytoreductive surgery(p=0.041)and adjuvant therapy(p=0.044).Differences between groups were balanced by PSM.The Kaplan-Meier analysis showed that there were statistical differences in disease-free survival(DFS)(p=0.032)and overall survival(OS)(p=0.017)between the lymphadenectomy and no lymphadenectomy groups in the post-PSM cohort.There were no statistical differences in DFS(p=0.449)and OS(p=0.167)between the two groups in the FIGO stage Ⅱ/Ⅱ cohort of post-PSM cohort.However,there were statistical differences in DFS(p=0.011)and OS(p=0.046)between the two groups in the FIGO stage Ⅲ/Ⅳ cohort of post-PSM cohort.The COX proportional hazard regression analysis showed that age>50 years(p=0.026),FIGO stage Ⅲ/Ⅳ(p=0.027),and ineffective cytoreductive surgery(p=0.004)were risk factors associated with recurrence,while age>50 years(p=0.006)and ineffective cytoreductive surgery(p=0.001)were risk factors associated with death.In the lymphadenectomy group,the histological status of pelvic lymph nodes had no significant effect on DFS(p=0.205)and OS(p=0.114).Conclusions:Our study demonstrated that systematic lymphadenectomy was associated with DFS and OS.Age>50 years,FIGO stages Ⅲ/Ⅳ,and ineffective cytoreductive surgery were,however,high-risk factors associated with clinical prognosis in patients with LGSOC.Our study suggests that for patients with early-stage LGSOC,systematic lymphadenectomy may not be performed after comprehensive evaluation,but attention should be paid to occult lymph node metastasis.For patients with advanced LGSOC,systematic lymphadenectomy should be performed after comprehensive evaluation while undergoing cytoreductive surgery,but the prognostic value of patients with large residual lesions still needs further discussion.