Table 6 Clinical trials testing tamoxifen beyond 5 years

6,846^a

Pre- and post-menopausal women with ER⁺ EBC who already received T for 5 years (in the context of ATLAS trial total number = 12,894)

T for additional 5 years (10 years) versus stop T (5 years)

5-9 years RR 0.90 (0.79-1.02) P = 0.10 > 10 years RR 0.75 (0.62-0.90) P = 0.01

BC mortality: 5-9 years RR 0.97 (0.79-1.18) P = 0.74 BC mortality: >10 years RR 0.71 (0.58-0.88) P = 0.002

All years log-rank = 0.002

Absolute reduction at years 15: 3.7%

6,953

Invasive EBC who had already been taking T for 5 years. 2,755 ER⁺ (39%) and 4,198 ER untested (61%) (estimated 80% ER⁺ if status unknown)

T for additional 5 years versus no further treatment

RR 0.85 (0.76-0.95) P = 0.003

BC mortality: 5-9 years RR 1.08 (0.85-1.38)

Absolute reduction 4%

BC mortality: >10 years RR 0.75 (0.63-0.90) P = 0.007 BC mortality: all years RR 0.88 (0.74-1.03) P = 0.1

17,477

10,543^c ER⁺ from ATLAS plus 6,934 ER⁺ from aTTom

T 10 versus 5 years

NA

BC mortality: 5-9 years RR 0.97 (0.84-1.15)

BC mortality: >10 years RR 0.75 (0.65-0.86) P = 0.00004

BC mortality: all years RR 0.85 (0.77-0.94) P = 0.001