The Distribution And High-risk Factors Of Lymph Node Metastasis In Patients With Stage IB1 Cervical Cancer

Objective The purpose of our study was to analyze the clinicopathological features and distribution characteristics of lymph node metastasis(LNM)in patients with stage IB1 cervical cancer,to study the related risk factors for total lymph node metastasis and each group of lymph node metastasis,and to compare the clinicopathological features and risk factors for LNM in squamous cell carcinoma and adenocarcinoma.Materials and Methods 1.A case-control study was conducted to retrospectively collect clinicopathological and surgical information of the cervical cancer patients who were with stage IB1 according to International Federation of Gynecology and Obstetrics(FIGO)staging(2009),and to analyze the risk factors of lymph node metastasis.2.We brought primary cervical cancer patients with stage IB1 into our study,who did not undergo radiotherapy and chemotherapy before surgery and underwent the radical hysterectomy and pelvic lymphadenectomy in the Department of Obstetrics and Gynecology,Wuhan Union Hospital from January 2008 to December 2017.3.The patient's general medical information and clinicopathological information were extracted and recorded from the patient's medical record,including name,age,admission number,menopausal status,surgical procedure,date of surgery,tumor diameter,pathological type,and degree of differentiation,lymphovascular space invasion(LVSI),parametrial invasion(PI),the number of lymph nodes removed(RLN)and number of LNM,depth of stromal invasion,etc.4.The data of this study were analyzed by IBM SPSS Statistics 22.0 statistical software.Independent-samples T test was used to compare the RLN in different surgical ways.The differences of lymph node metastasis rate of each parameter were compared by chi-square test or Fisher's exact test.Risk factor analysis was performed by binary logistic regression analysis.The statistical significances were expressed by the odds ratio(OR)and its 95% confidence interval(CI).The difference was statistically significant at P<0.05.Results 1.A total of 728 patients with stage IB1 cervical cancer met the screening criteria,and the overall LNM positive rate was 14.6%(106/728).Among the LNM positive patients,59.4% were single-group LNM,and the unilateral LNM positive rate was 64.2%.There was no significant difference between the left and the right side of LNM(P>0.05).There are 20(18.9%)patients with LN skipping metastasis.In each group of lymph nodes(LN),the highest rate of LNM was obturator LN(8.5%),followed by internal iliac(5.4%),inguinal(3.2%),external iliac(2.3%),common iliac(1.9%),and parametrial LN(1.8%).There was no metastasis found in the presacral LN and para-aortic LN.There was a significant difference in the positive rate of LNM between the groups(P<0.05).When the tumor is bigger than or equal to 2 cm,the lymph node metastasis rates of the obturator,internal iliac,and common iliac are increased.When the tumor is smaller than 2 cm,the rate of common iliac LNM is 0%.Compared with adenocarcinoma,the rate of internal iliac LNM in squamous cell carcinoma was higher,and the differences are statistically significant.2.LVSI,PI,tumor larger than 2 cm,deep stromal invasion(DSI)and moderate-low differentiation were all risk factors for LNM.Among them,tumor larger than 2 cm(OR: 1.780,95% CI: 1.043-3.039),PI(OR: 2.930,95% CI: 1.262-6.801)and LVSI(OR: 5.022,95% CI: 3.074-8.204)were independent risk factors for LNM in stage IB1 cervical cancer.We used these three parameters to predict LNM,the area under curve(AUC)of the receiver operating characteristic curve(ROC)was 0.769,P <0.001.When the tumor was less than 2cm,PI was negative and LVSI was negative,we predicted that LNM was negative.The sensitivity for this way was 89.9%,the specificity was 43.6%,and the negative predictive value was 96.2%.When the tumor was larger than 2cm,PI positive and LVSI positive,we predicted that LNM was positive.The sensitivity for this way was 14.1%,the specificity was 99.0%,and the positive predictive value was70.0%.3.Compared with squamous cell carcinoma,adenocarcinoma had lower LVSI positive rate and better differentiation(P<0.05),while LNM positive rate was not statistically different among them.The independent risk factors for squamous cell carcinoma LNM were tumors larger than 2 cm(OR=1.799,95% CI: 1.022-3.166),PI(OR=3.166,95% CI: 1.243-8.065),and LVSI(OR=5.803,95% CI: 3.444-9.778),while the independent risk factor for adenocarcinoma LNM was LVSI(OR = 7.622,95% CI: 2.254-25.775).4.Analysis of lymph nodes in groups showed that the independent risk factors for LNM in each group were different.· Common iliac:PI(OR=9.928,95% CI:2.761-35.699),tumor larger than 3cm(OR=16.851,95% CI:2.128-133.423);· External iliac: PI(OR=8.689,95% CI:2.617-28.854),LVSI(OR=3.973,95% CI:1.244-12.691);· Inguinal: LVSI(OR=4.085,95% CI:1.615-10.336),DSI(OR=2.932,95% CI:1.132-7.596);· Obturator: Tumor larger than 2cm(OR=2.398,95% CI:1.178-4.882),LVSI(OR=6.071,95% CI:3.240-11.373);· Internal iliac: LVSI(OR=3.600,95% CI:1.710-7.578);·Parametrial:PI(OR=3.008,95% CI:1.115-8.114),LVSI(OR=3.284,95% CI:1.602-6.731).Conclusions The lymph node metastasis rate of IB1 cervical cancer is about 15%,obturator and internal iliac LNM are the most common,the rate of common iliac LNM is 0% when tumor smaller than 2cm,which can provide references for the extent of lymph node dissection.Tumors larger than 2 cm,PI,LVSI are independent risk factors for LNM in IB1 cervical squamous cell carcinoma,while LVSI is an independent risk factor for adenocarcinoma.