Role Of Postmastectomy Radiation Therapy In Breast Cancer Patients With Different Pathological Responses To Neoadjuvant Chemotherapy

Background Neoadjuvant chemotherapy was initially applied to patients with locally advanced breast cancer.Some studies have shown that neoadjuvant chemotherapy has certain advantages over postoperative adjuvant chemotherapy such as: 1.Shrinking tumors to reduce staging and increase breast-conserving opportunities;2.The sensitivity of cancer to chemotherapy agents can be intuitively understood.In recent years,the use of neoadjuvant chemotherapy has become more and more widely.Some operative patients also begin to select neoadjuvant chemotherapy.Due to the down stage of neoadjuvant chemotherapy,the traditional guidelines for postmastectomy radiation therapy(PMRT)cannot fully suitable for patients after neoadjuvant chemotherapy.Therefore,there is no uniform standard for the indication of PMRT after neoadjuvant chemotherapy.The purpose of the present study was to investigate the role of PMRT after neoadjuvant chemotherapy in breast cancer patients of clinical stage?–? with different pathological responses to neoadjuvant chemotherapy.Methods We retrospectively analyzed 79 clinical stage?–? breast cancer patients who underwent mastectomy after neoadjuvant chemotherapy between 2008 and 2013 in Shandong cancer hospital.The pathological type was invasive ductal carcinoma,and the resection margin was negative.The total radiation therapy dose was 50-52 Gy.The standard schedule consisted of daily fractions of 1.8-2.0Gy.The 5-year loco-regional recurrence-free survival(LRRFS),distant failure free survival(DFFS)and overall survival(OS)were compared between the patients with and without radiotherapy in good response subgroup.The 5-year LRRFS,DFFS and OS were also compared between the patients with and without radiotherapy in poor response subgroup.The 5-year curves for LRRFS?DDFS and OS were constructed using the Kaplan–Meier method,and the difference using the log–rank test and the difference was statistically significant(P<0.05).Results A total of 79 patients met the inclusion criteria,with a median age of 48 years and a median follow-up period of 56 months.There were 46 patients in the radiotherapy group and33 in the non-radiotherapy group.The 5-year LRRFS,DFFS,and OS in the two groups were97.8% and 81.8%(P=0.01),73.9% and 75.8%(P=0.92),84.8% and 84.8%(P=0.96),respectively.The subgroup analysis showed that 41 patients with good response,the 5-year LRRFS,DFFS,and OS of radiotherapy and non-radiotherapy patients were 100% and 93.8%(P=0.21),84.0% and 81.3%(P=0.85),88.0% and 81.3%(P=0.32),respectively.38 patients with poor response,5-year LRRFS,DFFS,and OS were 95.2% and 70.6%(P=0.03),61.9%and 70.6%(P=0.71),81.0% and 88.2%(P=0.59),respectively.Conclusions When the pathological response was good,the loco-regional recurrence was low;and when the pathological response was poor,the loco-regional recurrence was high.The local benefits of PMRT were greater in patients with poor response.