Analysis Of Clinicopathologic Characteristics And Prognosis Of De Novo Metastatic Breast Cancer

Objective: To analyze and compare the clinicopathological characteristics and prognosis between de novo metastatic breast cancer(DnMBC)and recurrent metastatic breast cancer(rMBC),and analyze the prognosis factors of DnMBC in-depth.Methods: In this retrospective case-controlled study,243 female patients with DnMBC from Tianjin Medical University Cancer Institute and Hospital were included as the DnMBC group between January 2006 and December 2017,and 972 female patients with rMBC were selected according to the matching conditions during the same period.Clinical and pathological characteristics and prognostic factors were analyzed by SPSS25.0 statistical software.Graph Pad Prism7 software was used for drawing.P<0.05 was considered statistically significant.Results: In this study,243 patients of DnMBC group and 972 patients of rMBC group were reported.Compared with rMBC,patients with DnMBC had a higher median age(52 years vs.49 years),higher proportion of tumor T3-4(53% vs.12.7%),higher proportion of axillary lymph node N2-3(65.6% vs.36.4%),higher proportion of bone metastasis in first single organ metastasis(51.9% vs.22.6%),higher proportion of first-line chemotherapy(94.6% vs.83.9%)and higher proportion of surgical treatment(27.6% vs.14.7%).The median follow-up time was 28(2-155)months,the median overall survival(OS)were 35(30-40)in DnMBC and 30(28-32)months in rMBC,respectively(P=0.047).In rMBC,the median OS of patients with DFI<2 years,≥2 years and<5 years,≥5years were 24 months,29 months,and 46 months,respectively(P<0.001).Compared with DnMBC patients,rMBC patients with DFI<2 years(P < 0.001),≥2 years and <5years(P=0.02)had worse OS,while rMBC patients with DFI≥5 years(P=0.008)had longer OS,and the differences were statistically significant.Univariate analysis showed that menstrual status,T stage,ER status,PR status,HER2 expression,Ki-67 index,number of first metastatic organs and visceral metastasis were associated with PFS in DnMBC(P<0.05).T stage,N stage,ER status,PR status,HER2 expression,Ki-67 index,number of first metastatic organs,single organ metastasis site,visceral metastasis,anti-HER2 treatment in HER2 positive patients and primary breast cancer surgery were associated with OS in DnMBC(P<0.05).Multivariable analysis revealed that ER status and Ki-67 index were highly significant independent predictors of PFS in DnMBC(P<0.05).T stage,N stage,ER status,visceral metastasis and surgical treatment of primary tumors were highly significant independent predictors of OS in DnMBC(P<0.05).Univariate analysis showed that N stage,ER status,PR status,initial treatment and anti-HER2 treatment in HER2 positive patients were associated with OS in rMBC(P<0.05).N stage,ER status,PR status,and initial treatment were highly significant independent predictors of OS in rMBC(P<0.05).Subgroup analysis of DnMBC patients showed that PFS and OS in HR+/HER2-group were better than those in HR±/HER2+ and HR-/HER2-groups,in non-visceral metastasis group were better than those in visceral metastasis group,and in the group receiving primary tumor surgery regardless of the surgical method were better than those not.In HR+/HER2-、HR±/HER2+ groups,the OS of patients who underwent surgical treatment was longer than those without surgery(P=0.011,P=0.004).In the single bone metastasis group,the OS of the patients receiving surgical treatment was longer than those without surgery(P=0.032).Conclusion: Compared with rMBC in the same period,DnMBC patients have stronger tumor aggressiveness,more active treatment and better prognosis.DFI is an important factor affecting the prognosis of rMBC patients.Palliative surgical treatment may improve the prognosis of patients with single bone metastasis,non-triple negative DnMBC.