The Relationship Between Molecular Subtyping Of Breast Cancer And The Feasibility Of Breast-conserving Surgery

Purpose and backgroundBreast cancer ranks first in the global female malignancies and it is a heterogeneous malignancy.Different molecular subtypes of breast cancer have different biological behavior and prognosis.Molecular typing of breast cancer plays an increasingly important role in the individualized treatment of breast cancer patients.At present,breast-conserving surgery has become an important treatment for clinical stage I and II breast cancer.There was no significant difference between breast-conserving surgery and radical surgery for survival rate,but for the local recurrence rate,the former was significantly improved.Although the multivariate analysis in some studies showed that patients age,tumor size,positive axillary lymph nodes,no adjuvant chemotherapy or endocrine therapy associated with local recurrence,but the margin status is still the most important risk factor.Data showed that the negative margins of recurrence rate is low,which 5-year recurrence rate was 3% to 4% and positive margins were 12% to 20%.Completely removed and negative margins are the primary factor for the success of breast-conserving surgery and low local recurrence rates.It has been reported that the positive margins correlate with tumor size,age,lymph node positive,lymphatic vessel invasion and a wide range of intraductal carcinomas,but the relationship between molecular typing and marginal status has not yet been clarified.In this study,the relationship between molecular typing of breast cancer and the feasibility of breast-conserving surgery was studied by analyzing the molecular classification of breast cancer and the status of breast-conserving surgery and the prognosis of patients.The results have important reference value and guiding role for clinical breast-conserving surgery patients' choice,surgical methods,margin of resection and comprehensive treatment.MethodsRetrospectively analyzed the clinical and pathological data in 235 patients of breast cancer in Shandong Cancer Hospital from January 1,2010 to February 28,2017.According to the molecular classification,patients were divided into four groups: luminal A,luminal B,HER2-enriched and triple-negative.The clinicopathological features of the four groups were analyzed and compared.Logistic regression analysis were used to analyze the influencing factors of positive margins,and the relationship between different subtypes and marginal status.A total of 223 cases of breast-conserving surgery patients were followed up.Cox regression analysis were used to analyze the influencing factors of progression-free survival.Using Kaplan-Meier for survival analysis in different molecular types,and Log-rank test.ResultsThe breast-conserving success rate was 94.9%(223/250).There were statistically significant difference in age(P=0.04),tumor size(P=0.03),tumor grade(P<0.001),and neoadjuvant therapy(P=0.04)among different molecular subtypes.The presence of mammographic calcification was associated with positive margins(OR=2.02,P=0.049),whereas molecular typing(P=0.30)did not affect breast conserving margins and was not associated with neoadjuvant chemotherapy(P>0.05).In the luminal A group,the positive margin was associated with mammographic calcification(P=0.02)and tumor grade(P=0.03),whereas no statistically significant factors were observed in other groups.The risk of recurrence and metastasis was significantly higher in patients with axillary lymph node metastasis than those without lymph node metastasis(HR=3.448,P=0.03).Patients receiving adjuvant radiotherapy had a lower risk of recurrence and metastasis(HR=0.077,P<0.001).HER2-enriched(HR=7.734,P=0.03)and triple-negative(HR=5.910,P=0.01)patients had higher risk of recurrence and metastasis.Patients with different subtypes of breast cancer had statistically significant differences in progression-free survival(P=0.03),and luminal A patients had the best prognosis,luminal B take second place,and triple-negative patients with the worst prognosis.ConclusionsMolecular typing is not a risk factor for marginal state in breast-conserving surgery.It might be thought that no wider margins are necessary to control the more aggressive tumor types.Although the adjuvant treatment are different in the four molecular types,the molecular subtyping may not affect the feasibility of breast-conserving surgery.