|Scrutinizing the evidence for breast
cancer procedures and treatments
|ATLAS Tamoxifen Trial
Key question to
Is information patients
receive based on
of care "consensus" or
evidence based overall
Dr. Eric Winer from Dana
Farber Cancer Institute
Aromatase Inhibitors as
adjuvant therapy offer no
ATLAS (Adjuvant Tamoxifen, Longer Against Shorter):
International randomized trial of 10 versus 5 years of adjuvant
tamoxifen among 11,500 women – preliminary results.
Peto R, Davies C, on behalf of the ATLAS Collaboration.
Background: In estrogen receptor positive (ER+) early breast
cancer, 5 years of tamoxifen substantially reduces the annual
recurrence rate throughout the first decade (years 0-9). Despite
this, appreciable risks of recurrence remain, and are persistent.
Even with 5 years of tamoxifen, the annual recurrence risks for ER+
disease are comparably high during years 0-4, years 5-9 and years
10-14 (and perhaps beyond). It is not reliably known how 10 years of
adjuvant tamoxifen compares with the current standard duration of
tamoxifen, which is just 5 years.
Methods: During 1996-2005, ATLAS randomized 11 500 women (59%
ER+, 41% ER untested) in 420 hospitals in 38 countries who had
completed ~5 years of adjuvant tamoxifen between continuing for
another 5 years (ie, to a total of 10 years) and control (ie, stopping).
The annual follow-up recorded information on compliance, hospital
admission(s), breast cancer recurrence (including new
contralateral disease), incidence of other new primary cancer,
death and cause of death. Halfway through the trial treatment
period, 83% of those allocated to continue and 4% of those
allocated to stop were still taking adjuvant tamoxifen; <1% had
switched to any other adjuvant hormonal treatment.
Results: During ~48 000 woman-years of follow-up after
randomization (mean 4.2 years per woman), the annual recurrence
rate in each of the two treatment groups was approximately
constant during and after the five-year trial treatment period (ie,
during years 5-9 and 10-14 after first starting tamoxifen). Some 1500
recurrences have been reported, ~1300 during years 5-9 but, in
these preliminary results, only ~200 during years 10-14. Overall, the
recurrence rate was significantly lower among those allocated to
continue tamoxifen. There was no significant heterogeneity in this
recurrence rate reduction with respect to ER status (ER+ or ER
untested), time period (years 5-9 or 10-14), age or nodal status (at
the time of diagnosis). There were ~700 deaths after recurrence
(mostly from breast cancer) and ~500 deaths before recurrence (all
from other causes).
Although breast cancer mortality and overall mortality were lower
among those allocated to continue, these differences were not
statistically significant. There were no significant differences in
mortality before recurrence, either overall or from particular
Discussion: This large study shows that continuation of tamoxifen
beyond the first 5 years reduces recurrence over the next few
years, but further follow-up is needed to assess reliably the longer-
term effects on recurrence and the net effects, if any, on mortality.
|Tamoxifen studies conducted
show no overall (all cause)
survival benefit when carried
out longer than five years.
According to the ATLAS trial,
while Tamoxifen has some
small statistical benefit in
reducing recurrence, the
widely prescribed drug does
not appear to show it
lengthens the lives of breast
Breast Cancer Choices
encourages physicians to
disclose the overall survival
statistics to patients.
What are the hidden
statistics in treatment
How to ask your doctor
for "overall survival"
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