A Clinical Study On Selective Elimination Of Breast And Axillary Surgery After Neoadjuvant Chemotherapy For Breast Cancer

Objective:Neoadjuvant chemotherapy(NAC)is widely used as an efficient breast cancer treatment.Ideally,a pathological complete response(pCR)can be achieved.With improvements in molecular typing guided NAC and targeted therapies,there has been dramatic improvement in pCR rates,especially among triple-negative(TN)and human epidermal growth factor receptor 2(HER-2)positive breast cancers.Rates of pCR in these groups of patients can reach 60%or higher.After NAC.pCR can not only be used as a surrogate for long-term survival for breast cancer patients,but also affect the loco-regional de-escalating treatment of breast cancer.Patients who have achieved pCR after NAC still have to undergo breast and axillary surgery,and do not consider the obvious degree of pathological remission.Given the high pCR ratio of some subgroups after NAC,it should be questioned whether the surgery is redundant in the whole process of breast cancer management.This study was designed to prospectively evaluate the accuracy of ultrasound-guided multi-point core needle biopsy(CNB)in predicting breast pCR(breast pCR,bpCR)after NAC.And It aimed to explore the optimal time of sentinel lymph node biopsy(SLNB)and NAC,and to assess which patients would acquire greater benefits from selective elimination of axillary surgery by retrospectively analyzing the correlation between different clinicopathological characteristics of clinically nodal-negative(cN0)patients and axillary lymph node negative after NAC(ie,ypN0).Methods:This study is a one-armed clinical research conducted from June 2017 to October 2018.A total of 37 breast cancer patients from Shandong Cancer Hospital affiliated to Shandong University who achieved breast radiologic complete response(brCR)or partial response after NAC were enrolled in the study.Conventional breast surgery(breast-conserving surgery or mastectomy)was performed after NAC,and then ultrasound-guided multipoint CNB was performed on the postoperative specimens.The pathological results of CNB specimens was compared with the surgical specimens to evaluate the accuracy of CNB for predicting bpCR(ie,ypT0)after NAC.At the same time,the relationship between the different clinicopathological characteristics of 138 cN0 patients who received NAC and ypN0 after NAC from October 2010 to April 2018 were retrospectively analyzed.In the initial cN0 patients,some patients after NAC underwent directly axillary lymph node dissection(ALND);some patients underwent SLNB and then switched to ALND;some patients underwent SLNB,and Intraoperative sentinel lymph node(SLN)print cytology and rapid pathological examination of frozen,ALND only for SLN positive patients.Results:Of the 37 patients enrolled prospectively,18(48.6%,18/37)patients achieved bpCR after NAC.Univariate analysis showed that molecular subtypes of the breast tumor,post-NAC brCR and axillary pathological complete respons were significantly associated with bpCR(P=0.013,P=0.039 and P=0.001,respectively).Ultrasound-guided multipoint CNB for predicting the accuracy,negative predictive value(NPV)and false negative rate(FNR)of bpCR after NAC were 91.9%,90.0%and 10.5%,respectively,which were superior to ultrasound,mammography,MRI and a joint examination of the three.Imaging combined with ultrasound-guided multipoint CNB for predicting bpCR after NAC did not improve NPV comparing with CNB alone,but FNR was significantly lower(5.3%vs 10.5%;P<0.001)Among the 138 cN0 patients,81.9%(113/138)were ypNO.The rates of ypNO after NAC in patients with hormone receptor positive(HR+)/HER2-,HR+/HER2+,HR-/HER2+ and TN breast cancer were 75.4%(15/61),81.0%(17/21),79.2%(19/24)and 96.9%(31/32),respectively(P<0.001).The rates of ypNO after NAC in patients with HER2+(with targeted therapy)and TN were 94.1%(16/17)and 96,9%(31/32).respectively,which were significantly higher than that in HR+/HER2-patients(P<0.05).Molecular subtypes,clinical stage,brCR and bpCR correlated with ypNO after NAC(with full-course chemotherapy.P<0.05).Molecular subtypes(OR=0.454,P=0.049),clinical stage(OR=3.174,P=0.029)and bpCR(OR=0.337,P=0.016)of the breast tumor were independent predictors for ypNO after NAC.Conclusions:1.Ultrasound-guided multipoint CNB has the potential to accurately predict bpCR after NAC,making it possible to selectively eliminate breast surgery after NAC for breast cancer.2.The optimal time of SLNB and NAC in cNO patients might be different among different molecular subtypes:it would be preferable to perform SLNB prior to NAC for HR+/HER2-patients,and SLNB after NAC for HER2+(with targeted therapy)and TN patients to reduce the risk of ALND.3.In view of the high ypNO rate after NAC in cN0 patients,axillary surgical staging might be selectively eliminated,especially in patients with HER2+(with targeted therapy)and TN breast cancer.