Study On Factors Affecting Prognosis Of Primary Breast Angiosarcoma

Background: Primary breast angiosarcoma is an extremely rare malignant tumor,which is characterized by the high degree of malignancy,rapid progression and poor prognosis.Because of its low incidence,there are almost no prospective studies but small retrospective reviews and case reports.Previous studies have not reached a unified conclusion on the factors affecting the prognosis of primary breast angiosarcoma.Especially,the effects of breast-conserving surgery and mastectomy on the prognosis are controversial.Objective: The purpose of this study is to analyze the factors affecting the prognosis of primary breast angiosarcoma by propensity score matching,competitive risk model and Cox proportional hazard model,and to explore the effects of different surgeries on the prognosis of primary breast angiosarcoma.Methods: The baseline data and survival data of female patients with primary breast angiosarcoma diagnosed from 1983 to 2015 were retrieved online in the Surveillance Epidemiology and End Result(SEER)database.Survival curves were drawn to compare the survival rates of patients in different groups.Cox proportional hazard model was used to analyze the related prognostic factors.Then,the patients were divided into two groups by surgery.Propensity score matching was used to minimize the influence of uneven distribution of baseline data of patients in different surgery groups.Finally,the effects of breast-conserving surgery and mastectomy on the prognosis of patients were analyzed.Results: 1.A total of 164 patients with breast angiosarcoma were enrolled.The Kaplan-Meier survival curve showed that there were significant differences in survival rates among groups of different ages,tumor sizes,tumor differentiation,tumor stages and surgeries(P<0.05).Multivariate Cox analysis showed that the late year of diagnosis(2009-2015),old age,large tumor size,low tumor differentiation,advanced tumor stage and mastectomy were independent risk factors while the chemotherapy after surgery was the independent protecting factors affecting the prognosis of primary breast angiosarcoma(P<0.05).2.The patients were divided into breast-conserving surgery group of 29 patients and mastectomy group of 135 patients.Gray test and cumulative incidence curve of sarcoma-specific death were performed in the competitive risk model.Results showed that the risk of tumor-specific death was higher for the patients receiving mastectomy(P<0.05).With the increase of follow-up time,the incidence of tumor-specific death in mastectomy group was always higher than that in breast-conserving surgery group.There were significant differences in age and tumor size between the two groups(P<0.05).Thus the propensity score matching was used and 54 patients were finally enrolled,with 27 patients in each group.Kaplan-Meier curve and Cox univariate regression showed that the survival rate of patients in breast conserving surgery group was higher,and mastectomy was a risk factor for overall mortality(HR: 2.65,95%CI: 1.18-5.93,P<0.05).In the competitive risk model the cumulative incidence of tumor-specific death in mastectomy group was still higher than that in breast conserving surgery group.Conclusion: The late year of diagnosis(2009-2015),old age,large tumor size,low tumor differentiation,advanced tumor stage and mastectomy are independent risk factors while the chemotherapy after surgery is the independent protecting factors affecting the prognosis of primary breast angiosarcoma.The cumulative incidence of tumor-specific death of mastectomy group was higher than that of breast-conserving surgery group.