Effect Of Breast Conservation Therapy And Modified Radical Mastectomy On The Prognosis Of Patients With Stage ? Breast Cancer

Objective: In this study,we analyzed the survival of patients with stage II breast cancer undergoing breast-conserving surgery plus radiotherapy(BCT)and modified radical mastectomy(MRM)and evaluated the impact of the two procedures on the survival and prognosis in stage II breast cancer patients with different characteristics,which aimed at providing a theoretical basis for the surgical selection of breast cancer patients.Methods: This study was a registry-based analysis involving patients with stage II breast cancer who underwent BCT and patients who underwent MRM between January 1,1998,and December 31,2010,in the SEER database.Propensity-score matching was used to assemble a cohort of patients with similar baseline characteristics.The comparative risks of outcomes were further adjusted for in the matched cohort with the use of a Cox proportional-hazards regression model that was stratified on the matched pair to preserve the benefit of matching.The primary outcome was all-cause mortality.Secondary outcomes were breast cancer specific mortality.Results: Among 136,419 eligible patients,50,935 patients who underwent BCT and 50,935 who underwent MRM had similar propensity score and were included in the analyses.At a mean follow-up of 9.9 years,OS curve and BCSS curve showed that the five-year?ten-year and fifteen-year survival rates of OS and BCSS in the group of patients that underwent BCT were 88.6%?75.0%?62.4% and 98.7%?96.3%?93.4%,which were higher than those that underwent MRM(OS: 83.5%,68.2%,55.0% vs BCSS: 97.7%,94.6%,91.1%),and the prognosis between the two groups was significantly different(P<0.001).BCT,as compared with MRM,was associated with a lower risk of death(hazard ratio,0.758;95% confidence interval [CI],0.741 to 0.776;P<0.001)and breast cancer-specific death(hazard ratio,0.754;confidence interval [CI],0.728 to 0.782;P<0.001).The results were generally similar in subgroup analyses.The patients with age older than 65(65-78: hazard ratio,0.736;confidence interval [CI],0.709 to 0.765;P<0.001;>78: hazard ratio,0.709;confidence interval [CI],0.675 to 0.745;P<0.001)?infiltrative specific type of carcinoma(hazard ratio,0.741;confidence interval [CI],0.706 to 0.777;P<0.001)?Grade ? and ?(Grade ?: hazard ratio,0.683;confidence interval [CI],0.639 to 0.703;P <0.001;Grade ?: hazard ratio,0.730;confidence interval[CI],0.704 to 0.756;P <0.001)?ER positive(hazard ratio,0.740;confidence interval [CI]: 0.720 to 0.760;P <0.001)undergoing BCT associated with a favorable prognosis for OS than undergoing MRM.Conclusions: In a population-based cohort with stage II breast cancer,BCT,as compared with MRM,was associated with a lower risk of death and breast cancer specific death.The magnitude of this benefit was greater among patients with age older than 65?infiltrative specific type of carcinoma?Grade ? and ? and ER positive.