The Silva Classification System Of Endocervical Adenocarcinoma And Its Correlation With Clinicopathological Features And Prognosis

Background and objectivesEndocervical cancer is one of the most common gynecologic malignancy,and most of them are associated with high-risk human papillomavirus(HPV)infection.Endocervical adenocarcinoma is the second most frequent endocervical carcinoma following squamous cell carcinoma,and its incidence has been increasing in recent decades,accounting for 25% of all endocervical cancers.Although squamous cell carcinoma and endocervical adenocarcinoma have different histologies sites of origin,prognostic factors,and patterns of spread,they are staged and treated similarly.A novel method of stratifying patients into risk categories based on the pattern of stromal invasion has been proposed for endocervical adenocarcinoma.This new system,the Silva system,has the potential to considerably reduce the number of unnecessary radical procedures.The Silva classification system is only limited to HPV-related endocervical adenocarcinoma.According to the classification,endocervical adenocarcinomas are divided into patterns A,B,and C.There were some studies about the clinicopathological features of the Silva classification system and the relationship between the Silva classification system and some prognostic factors,but the number of analysis was less and it is still unclear whether other potential prognosticators should be added to better define Silva system.In the present study,we reviewed the histological sections of endocervical adenocarcinomas,analysed the clinicopathological features of the Silva classification system,and the prognosis of micropapillary patten、cribriform pattern and retraction clefting.We explored whether the patterns could be a potential factor added to better define Silva system.We also design Silva score as a supplementary prognostic grade group system.Materials and methodsCases of endocervical adenocarcinoma were selected from archival files in the Department of Pathology,The Second Hospital of Jilin University.All cases were followed up and the history and clinicopathological features of the follow-up cases were analyzed retrospectively.The morphological characteristics of Silva classification、 micropapillary patten、cribriform pattern and retraction clefting were recorded.Inferential analysis was performed to compare clinicopathologic variables data between pattern subgroups using SPSS.Kaplan-Meier plots and the log-rank test were used to compare the independent variables and survival.Results1.There were 333 cases of endocervical adenocarcinoma we collected,of which 300 cases were human papilloma virus related,accounting for 90.0%.This study fit into 120 patients who were followed up.Silva C demonstrated the highest frequency of 72.5% among the cases reviewed,followed by Silva B,accounting for 18.3%,and Silva A,accounting for 9.2%.2.Among the three types of Silva pattern,there were statistical differences with the degree of tumor differentiation、the frequency of invasion depth>1/2,the frequency of lymphatic vascular space invasion,FIGO stage and the frequency of pelvic lymph node metastasis(P<0.05),but there were no statistical differences with age distribution and the frequency of accompanying HSIL among the three groups(P>0.05).3.There were 31(25.8%)cases showed micropapillary patten,of which 25(80.6%)cases were Silva C,6(19.4%)cases were Silva B.The frequency of lymphatic vascular space invasion,pelvic lymph node metastasis and the frequency of invasion depth>1/2 showed statistical difference between micropapillary patten and none-micropapillary patten cases(P<0.05)in the 120 cases.The cases with micropapillary patten are more likely to have lymph vessel space infiltration and pelvic lymph node metastasis,and more likely to have a deeper invasion.4.There were 64(53.3%)cases showed cribriform patten,of which 3(4.7%)cases were Silva A,17(26.6%)cases were Silva B,44(68.8%)cases were Silva C.The Silva system,FIGO stage,the frequency of lymphatic vascular space invasion,the frequency of invasion depth>1/2 showed statistical difference between cribriform pattern and none-cribriform patten cases(P<0.05)in the 120 cases.The cases with cribriform pattern are more likely to have a deeper invasion,but demonstrate neither advanced FIGO stage nor pelvic lymph node metastasis.5.There were 34(28.3%)cases showed retraction clefting and all of them were Silva C.The Silva system,FIGO stage,the frequency of lymphatic vascular space invasion,the frequency of invasion depth>1/2,pelvic lymph node metastasis showed statistical difference between retraction clefting positive and retraction clefting negative cases(P<0.05)in the 120 cases.The cases show retraction clefting are all Silva C.These cases show advanced FIGO stage,are more likely to have lymph vessel space infiltration and pelvic lymph node metastasis.6.The median follow-up time was 54 months(25-95 months).19 patients were dead and24 patients with recurrence or metastasis.The 1-year overall survival rate was 91.7%,the 3-year overall survival rate was 86.5%,and the 5-year overall survival rate was 84.2%.7.Silva score、differentiation、depth of invasion、lymph vascular space invasion、FIGO stage、pelvic lymph node metastasis、micropapillary patten are related to prognosis of endocervical carcinoma(P<0.05).High Silva score、poor differentiation、invasion depth>1/2、advanced FIGO stage、pelvic lymph node metastasis positive、micropapillary patten were related to the shortening of overall survival and disease-free survival.8.At the multivariate analysis,Silva score was an independent poor prognostic factor of overall survival and disease-free survival of endocervical carcinoma.Pelvic lymph node metastasis was an independent poor prognostic factor of overall survival of endocervical carcinoma.Conclusions1.Silva C demonstrated the highest frequency in cervical adenocarcinoma.The patients with higher Silva pattern are more likely to have poorer differentiation,deeper invasion,lymph vascular space invasion,pelvic lymph node metastasis,but there was no significant difference in overall survival and disease-free survival.2.Silva score shows a batter predictive value to the overall survival and disease-free survival than Silva pattern in endocervical adenocarcinoma.3.We suggest revising the Silva C criteria by adding papillary patten and retraction clefting as factors and propose expanding the Silva pattern system to include more histologic variants.