| BackgroundBreast cancer is the most common malignant tumor in women,which seriously threatens women’s health.Triple-negative breast cancer(TNBC)is a highly heterogeneous disease that is defined by a lack of expression of estrogen receptor,progesterone receptor,and human epidermal growth factor receptor-2.TNBC is characterized by younger age at diagnosis,higher invasiveness,higher risk of early recurrence,tendency to visceral and brain metastases,and significantly shorter median survival and disease-free survival than other breast cancer subtypes.Because there is no precise target for treatment,systemic treatment of TNBC still relies on chemotherapy.For early stage breast cancer,the current two mainstay treatments are breast-conserving therapy(lumpectomy followed by radiotherapy,BCT)and mastectomy(with or without radiotherapy).However,the guidelines do not further address the molecular subtypes of breast cancer.Besides,considering poor prognosis of patients with TNBC,whether patients with TNBC should be performed more aggressive local treatment remains unclear.Therefore,we want to clarify the question whether there are survival differences among T1-2N0M0 TNBC patients treated with BCT,mastectomy alone or mastectomy with radiotherapy based on a population retrospective analysis from Surveillance,Epidemiology,and End Results(SEER)database,which provides a theoretical basis for the clinical formulation of the best treatment scheme for triple negative breast cancerMethodsBased on the SEER database,patients with T1-2N0M0 TNBC were included according to certain inclusion criteria.Patients were divided into three groups according to surgery modality and radiotherapy(RT):BCT,mastectomy alone,and mastectomy with radiotherapy.The Chi square test was used to examine the differences in demographics and tumor characteristics between the three groups.The survival endpoints were overall survival(OS)and breast cancer specific survival(BCSS).Cox proportional hazards model was used to estimate risk factors for OS and BCSS.Univariate analysis incorporated all variables and multivariate analysis was performed according to univariate results and clinical consideration,95%confidence intervals for the hazard ratios(HR)were calculated.And survival analysis was performed using the Kaplan-Meier method and the log-rank test among treatment types.Statistical significance was found at P values<0.05.ResultsA total of 14,910 female with T1-2N0M0 TNBC were included.Among them,there were 7,381 cases of patients treated with BCT,6,967 cases of mastectomy and 562 cases of mastectomy with radiotherapy.Cox multivariable analysis showed that local treatment was an independent risk factor for OS and BCSS.It showed that patients subjected to BCT had an improved OS(HR=0.717,95%CI:0.639-0.803,P<0.001)but similar BCSS(HR=0.930,95%CI:0.781-1.108,P=0.418)compared with mastectomy.Patients treated with mastectomy with radiotherapy had a higher mortality risk as women who underwent mastectomy alone(OS:HR=1.319,95%CI:1.093-1.771,P=0.007;BCSS:HR=2.071,95%CI:1.546-2.776,P<0.001).Patients with BCT had superior OS and BCSS than those treated with mastectomy alone(OS:log-rank P<0.001;BCSS:log-rank P=0.016)and mastectomy with radiotherapy(OS:log-rank P<0.001;BCSS:log-rank P<0.001).Patients receiving mastectomy with radiotherapy had similar OS(log-rank P=0.153)and worse BCSS(log-rank P<0.001)compared with mastectomy alone.The 5-year OS was 88.6%for BCT,83.0%for mastectomy alone and 79.6%for mastectomy with radiotherapy,respectively.The 5-year BCSS was 94.3%for BCT,93.3%for mastectomy alone and 83.7%for mastectomy with radiotherapy,respectivelyConclusionBased on this population-based retrospective analysis,we found that BCT was associated with superior survival compared to mastectomy with or without radiotherapy in patients with T1-2N0M0 TNBC.After mastectomy,there was no evidence of survival benefit of RT.We,therefore,supposed that BCT was the more suitable locoregional treatment for patients with T1-2N0M0 TNBC. |
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