Continuing Adjuvant Tamoxifen to 10 Years

ATLAS Christina Davies,et al. Lancet 2013; 381: 805–16

Figure 3A: Recurrence by treatment allocation for 6846 women with ER-positive disease

Figure 3B: Breast cancer mortality by treatment allocation for 6846 women with ER-positive disease

Figure 4: Recurrence by treatment allocation for 6846 women with ER-positive disease, subdivided by patient or tumour characteristics and location or time of first recurrence

Conclusions aTTom confirms that, in ER+ disease, continuing tamoxifen to year 10 rather than just to year 5 produces further reductions in recurrence, from year 7 onward, and breast cancer mortality after year 10. 10 years of adjuvant tamoxifen, compared to no tamoxifen, reduces breast cancer mortality by about one third in the first 10 years following diagnosis and by a half subsequently.

aTTom During 1991-2005, 6,953 women with ER+ (n=2755), or ER untested (4198, estimated 80% ER+ if status known) invasive breast cancer were, after 5 years of tamoxifen, randomized to stop tamoxifen or continue to year 10. Richard G. Gray, et al. J Clin Oncol, 2013, 31 (suppl)

RESULT OF aTTOM Allocation to continue tamoxifen reduced breast cancer recurrence (580/3468 vs 672/3485, p=0.003). Longer treatment also reduced breast cancer mortality (392 vs 443 deaths after recurrence, p=0.05) Non-breast-cancer mortality was little affected (457 vs 467 deaths, rate ratio 0.94 [0.82-1.07]). There were 102 vs 45 endometrial cancers RR=2.20 (1.31-2.34, p<0.0001) with 37 (1.1%) vs 20 (0.6%) deaths (absolute hazard 0.5%, p=0.02).