The Role Of Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy In Early Stage Breast Cancer Patients With YpN0

Purpose Radiation therapy has been used over the years as a supplemental treatment after surgery to resect tumors from the body.Some analyses recommended post BCS radiation therapy for patients with early node positive breast cancers.It was also discussed that omission of radiotherapy has also been associated with a large increase in risk of ipsilateral breast tumor recurrence and with a small increase in the risk of patient mortality.While the role of postmastectomy radiotherapy(PMRT)in pathologically node-positive,stage T1-2N1M0 breast cancer patients who achieved yp N0 after treated with neoadjuvant chemotherapy is still under considerable debate.Our objective was to investigate whether PMRT affects locoregional recurrence or survival outcomes in patients with pathologically node-positive,stage T1-2N1M0 breast cancer who reached yp N0 after treated with neoadjuvant chemotherapy and whether omission of PMRT in that setting is rational.Patients and Methods We retrospectively analyzed a total of 187 pathologically nodepositive,stage T1-2N1M0 breast cancer patients treated with NAC and modified radical mastectomy with and without PMRT who achieved yp N0 from 2003 to 2013 in our institution.Clinicopathologic characteristics were compared between groups using Chi-square test or Fisher exact test.Survival curves for LRR-free survival(LRRFS),DM-free survival(DMFS),DFS,and OS were performed by Kaplan-Meier method and compared to the log-rank test.The relative risk of LRRFS,DMFS,DFS or OS were included in the Cox proportional hazards regression model to carry out multivariate analysis.Results With a median follow-up of 5.1 years(range,0.7-11.3 years),5-year survival analysis was performed.For all the187 patients enrolled,the 5-year LRRFS,DMFS,DFS and OS were 94.6%,89.6%,86.7%and 96.2%,respectively.With the wholly 187 patients included,better DFS and DM were found in the experimental group when compared with the group in which patients who did not receive PMRT(p=0.023,0.049,respectively).But no statistical difference was confirmed on LRR or OS between two cohorts.We did not fond prognostic factors of OS in the univariable analysis,while positive LVI state(p = 0.048)and soft tissue involvement(p <0.001)were associated with decreased LRRFS.Age younger than 40 years was associated with worse DMFS(p =0.027).yp T stage was significant predictors of DFS(p =0.007).Multivariate analyses indicated that advanced yp T stage,treatment without PMRT and ?40 years were connected with worse DMFS and a reduced DFS time(P < 0.05 for all comparisons).Associations between soft tissue involvement and decreased LRRFS was established.Conclusions Our results suggest that pathologically node-positive,stage T1-2N1M0 breast cancer patients who achieved yp N0 treated post NAC and modified radical,but without PMRT were likely to have worse DM and DFS outcomes.We need to place weight on the lack of prospective data for omission of PMRT.So that it may still be necessary for these patients.PMRT in this setting can't be safely omitted and decision making for these patients should be individualized with clinicopathologic characteristics and patient preference taken into consideration.This conclusion should be validated by further prospective investigation in large cohorts.