Table 2

Treatment with TAM, its potential as a chemopreventive agent, and the potentially confounding effects of HRT on response to TAM

Early Breast Cancer Trialists Collaborative Group2-a(1992)
EndpointTAMControlReduction in RiskSignificance
Recurrence2,852 /15,0274,387 /15,05416% p < 0.000001
Contralateral breast cancers122 /9,128184 /9,13539% p < 0.000001
Mortality5,052 /15,0276,043 /15,05425% p < 0.000001
Recurrence or Prior DeathSignificanceDeath Any CauseSignificance
ER+ (n = 14,972)32% p  = 0.0000121%Significant
ER poor2-b (n = 5,366)13% p  = 0.00111% p = 0.02
Early Breast Cancer Trialists Collaborative Group (EBCTCG, 1998)
EndpointTAM ∼5 yrControlReduction ± S.D.Significance
Recurrence (ER+)692 /2,9661,110 /2,90350%  ± 4 p < 0.00001
Recurrence (ER poor)191 /446210 /4766%  ± 11N.S.
Death: any cause (ER+)655 /2,966812 /2,90328%  ± 5Significant
Death: any cause (ER poor)182 /446178 /476−3%  ± 11N.S.
Chemoprevention
StudyPlaceboTAMReduction in RiskSignificance
U.K. (Powles et al., 1998)3634 6%; 1.06 p = 0.8
 (n = 2,471)2-c  (0.7, 1.7)
Italian (Veronesi et al., 1998)2219 14% p = 0.6
 (n = 5,408)2-d
NSABP P-1 (Fisher et al., 1998) Relative riskSignificance
 (n = 13,388)2-e
Invasive cancers17589 49%; 0.51 p < 0.00001
 (0.39; 0.66)
Noninvasive cancers6935 50%; 0.50 p < 0.002
 (0.33, 0.77)
  • 2-a  Data are adapted from each study. Significance estimates are from the appropriate study. In some cases, the precise p-values are not available. N.S. = not significant.

  • 2-b  ER poor is generally taken as <10 fmol/mg protein.

  • 2-c  42% used HRT.

  • 2-d  TAM appears effective in 14% of women taking HRT (hazard ratio = 0.13; confidence interval = 0.02, 1.02).

  • 2-e  Subjects did not receive HRT.