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Table 2 Outcome results in the main phase III clinical trials testing adjuvant aromatase inhibitors

From: Status of adjuvant endocrine therapy for breast cancer

Study Arms DFS hazard ratio (95% CI) TTR or RFS hazard ratio (95% CI) TTDR or DRFI or DRFS or DDFS hazard ratio (95% CI) BCFI or BCFS hazard ratio (95% CI) OS hazard ratio (95% CI)
Monotherapy analysis (versus tamoxifen)
ATAC [53] 120-month follow-up A versus T versus T + A (5 years) 0.91 (0.83-0.99) P = 0.04 TTR 0.84 (0.75-0.93) P = 0.001 TTDR 0.87 (0.77-0.99) P = 0.03 NA 0.97 (0.88-1.08) P = 0.6
HR+ patients 0.86 (0.78-0.95) P = 0.003 HR+ patients 0.79 (0.70-0.89) P = 0.0002 HR+ patients 0.85 (0.73-0.98) P = 0.02 HR+ patients 0.95 (0.84-1.06) P = 0.4
BIG 1-98 [54] 8.1-year follow-up L versus T 0.53 (0.78-0.96) P = 0.007 NA DRFI 0.86 (0.74-0.998) P = 0.047 BCFI 0.86 (0.76-0.98) P = 0.03 0.87 (0.77-0.999) P = 0.048
IPCW 0.82 (0.74-0.92) P <0.0002   IPCW 0.79 (0.68-0.92) P = 0.003 IPCW 0.80 (0.70-0.92) P = 0.002 IPCW 0.79 (0.69-0.90) P <0.0006
TEAM [45] 2.75-year follow-up (before the switch) Upfront E (2.75 years) versus T 0.89 (0.77-1.03) P = 0.12 NA NA NA NA
Sequential therapy analysis
IES [46] 91-month follow-up T→ E versus T→ T (5 years) 0.81 (0.72-0.91) P <0.001 NA TTDR 0.84 (0.73-0.97) P = 0.01 BCFS 0.81 (0.71-0.92) P <0.001 0.53 (0.75-0.99) P <0.04
ARNO 95 [47] 30.1-month follow-up T (2 years)→A (3 years) versus T (2 years)→T (3 years) 0.66 (0.44-1.00) P = 0.049 NA NA NA 0.53 (0.28-0.99) P = 0.045
ABCSG Trial 8 [48] 60-month follow-up T (2 years)→A (3 years) versus T (5 years) 0.91 (0.75-1.103) P = 0.33 RFS 0.80 (0.631-1.013) P = 0.06 DRFS 0.78 (0.60-0.99) P = 0.046 NA 0.87 (0.64-1.16) P = 0.33
ITA [49] 128-month follow-up T (2-3 years)→A (5 years) versus T (5 years) NA RFS 0.64 (0.44-0.94) P = 0.02 NA BCFS 0.72 (0.44-1.17) P = 0.2 0.79 (0.52-1.21) P = 0.3
BIG 1-98 [54] 8.1-year follow-up L→T versus T→L (5 years) L→T 1.06 (0.91-1.23) P = 0.48 NA L→T DRFI 1.14 (0.92-1.42) P = 0.24 L→T BCFI 1.10 (0.91-1.32) P = 0.34 L→T 0.97 (0.80-1.19) P = 0.79
T→L 1.07 (0.92-1.25) P = 0.36 T→L 1.23 (0.99-1.53) P = 0.06 T→L 1.16 (0.96-1.40) P = 0.12 T→L 1.10 (0.90-1.33) P = 0.36
TEAM [55] 5-year follow-up (after the switch) E (5 years) versus sequential T→E 1.06 (0.91-1.24) P = 0.42 RFS 1.06 (0.88-1.28) P = 0.53 NA NA 1.00 (0.89-1.14) P >0.99
Extended therapy analysis
MA.17 [56] 64-month follow-up L versus placebo 0.68 (0.56-0.83) P <0.001 NA DDFS 0.81 (0.63-1.04) P = 0.09 NA 0.99 (0.79-1.24) P = 0.83
IPCW 0.52 (0.45-0.61) P <0.001 IPCW 0.51 (0.42-0.61) P <0.001 IPCW 0.61 (0.52-0.71) P <0.001
SCC 0.58 (0.47-0.72) P <0.001 SCC 0.68 (0.52-0.88) P = 0.004 SCC 0.76 (0.60-0.96) P = 0.02
ABCSG Trial 6 [51] 62.3-month follow-up A (3 years) versus no further treatment NA RFS 0.62 (0.40-0.96) P = 0.031 DFRS 0.53 (0.29-0.96) P = 0.034 NA 0.89 (0.59-1.34) P = 0.57
NSABP-33 [52] 30-month follow-up E (5 years) versus placebo (5 years) 0.68 P = 0.07 RFS 0.44 P = 0.004 NA NA NA
  1. →, switch to; A, anastrozole; ABCSG, Austrian Breast and Colorectal Cancer Study Group; ARNO 95, Arimidex-Nolvadex 95; ATAC, Arimidex, Tamoxifen, Alone or in Combination; BCFI, breast cancer-free interval; BCFS, breast cancer-free survival; BIG, Breast International Group; CI, confidence interval; DDFS, distant disease-free survival; DFS, disease-free survival; DRFI, distant relapse-free interval; DRFS, distant relapse-free survival; E, exemestane; HR+, hormone receptor-positive; IPCW, Inverse probability of censoring weighted; IES, Intergroup Exemestane Study; ITA, Italian Tamoxifen Anastrozole (trial); L, letrozole; NA, not available; NSABP, National Surgical Adjuvant Breast and Bowel Project; OS, overall survival; RFS, recurrence-free survival; SCC, approach proposed by Shao and colleagues [57]; T, tamoxifen; TEAM, Tamoxifen Exemestane Adjuvant Multinational; TTDR, time to distant relapse; TTR, time to relapse.