Abstract
BackgroundAdjuvant endocrine therapy undoubtedly prolongs the time to recurrence for patients with hormone-positive early breast cancer. Extended endocrine therapy to 10 years or longer has been expected to bring a greater clinical advantage. However, the related research conclusions are controversial.MethodsTamoxifen (TAM), Aromatase Inhibitor (AI), Exemestane, letrozole (LET) and anastrozole were used as key words in the literature search. After the patients completed 5 years of adjuvant endocrine treatment, they were allocated to continue endocrine treatment for 5 years or receive placebo/observation for 5 years. Disease-free survival (DFS) and overall survival (OS) were the end points. Systematic assessment was performed using Stata 12.0.ResultsTwelve trials including 30,848 cases were involved. The overall analysis demonstrated that extended endocrine therapy to 10 years significantly prolonged DFS compared with 5 years of endocrine therapy [hazard ratio (HR) = 0.84, 95% CI: 0.73–0.97]. Subgroup analysis showed that DFS was significant prolonged with TAM 5y - AI 5y treatment versus TAM 5y treatment and with (AI and/or TAM) 5y - LET 5y treatment versus (AI and/or TAM) 5y treatment [(HR = 0.61, 95% CI: 0.50–0.76) and (HR = 0.81, 95% CI: 0.71–0.93), respectively]. However, no significant difference was found in the DFS with TAM 5y - TAM 5y treatment versus TAM 5y treatment (HR = 0.97, 95% CI: 0.81–1.17). Overall and subgroup analysis did not demonstrate an OS benefit of therapy extended to 10 years. A DFS benefit of extended endocrine therapy to 10 years was verified in the lymph node-positive subgroup, postmenopausal subgroup and ER+ and/or PR+ subgroup (HR = 058, 95% CI: 0.45–0.75; HR = 0.70, 95% CI: 0.58–0.80; HR = 0.80, 95% CI: 0.67–0.96).ConclusionsAn extended 10 years of endocrine treatment yields a DFS benefit for patients with early breast cancer; (AI and/or TAM) 5y - AI 5y treatment is the optimal choice. ER+ and/or PR+, postmenopausal and lymph node-positive patients are the most suitable groups.
Highlights
Adjuvant endocrine therapy undoubtedly prolongs the time to recurrence for patients with hormone-positive early breast cancer
The analysis of Cochrane risk-of-bias showed that the methodological quality of all trials was relatively satisfied and fair
Subgroup 2 and subgroup 3 analysis showed that TAM 5y Aromatase Inhibitor (AI) 5y and (AI and/or TAM) 5y - LET 5y treatment significantly prolonged disease-free survival (DFS) compared with TAM 5y and (AI and/ or TAM) 5y treatment, respectively (HR = 0.61, 95% confidence interval (CI): 0.50–0.76; hazard ratio (HR) = 0.81, 95% CI: 0.71–0.93) (Additional file 2: Figure S1C, 1D)
Summary
Adjuvant endocrine therapy undoubtedly prolongs the time to recurrence for patients with hormone-positive early breast cancer. Li et al BMC Cancer (2018) 18:977 of AI to 10 years significantly reduced the recurrence risk after 5 years of adjuvant TAM and/or AI treatment [4,5,6]. In the NSABP-B33 trial, prolonged exemestane (EMT) for 5 years did not significantly decrease the recurrence compared with placebo [7]. The ATLAS, aTTom, E4181/ E5181 trials showed significant recurrence reduction by 10 years of TAM treatment compared with 5 years of TAM treatment; the Scottish trial demonstrated no benefit of extended adjuvant TAM [9,10,11,12]. The National Surgical Adjuvant Breast and Bowel Project (NSABP) B-14 reported extended TAM by more than 5 years led to a shorter DFS. All extended endocrine treatment did not bring an overall survival (OS) benefit [13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
