Biomedical Engineering Reference
In-Depth Information
A second prospective validation study including a population-
based study involving a case:cohort sample chosen from 4964
patients with node negative breast cancer diagnosed between
1985 and 1994 who did not receive adjuvant chemotherapy.
21
Cases included 220 patients who died from breast cancer, and
were individually matched to 570 controls with respect to age,
race, adjuvant tamoxifen, medical facility and diagnosis year and
were alive at the date of death of their matched case. About 50% of
patients had a low RS irrespective of tamoxifen used. After adjusting
for tumor size and grade, RS was significantly associated with risk of
breast cancer death in ER-positive, tamoxifen-treated and -untreated
patients (
= 0.03, respectively). At 10 years, the risks
for breast cancer death in ER-positive, tamoxifen-treated patients
were 2.8% (95% confidence interval [CI] 1.7-3.9%), 10.7% (95%
CI 6.3-14.9%), and 15.5% (95% CI 7.6-22.8%) for those in the low,
intermediate and high-risk RS groups, respectively. For those with
ER-positive tumors not treated with tamoxifen, the 10 year risk of
death was 6.2% (95% CI 4.5-7.9%), 17.8% (95% CI 11.8-23.3%),
and 19.9% (95% CI 14.2-25.2%), respectively. This study therefore
provided additional validation of the RS in a population-based study
of lymph node-negative, ER-positive breast cancer patients not
treated with chemotherapy, showing that RS was strongly associated
breast cancer death among ER-positive, tamoxifen-treated and
-untreated patients.
A third study provided information about the prognostic utility
of RS in patients treated with aromatase inhibitors (AIs), which
have been shown to be more effective than tamoxifen in preventing
recurrence in post-menopausal women.
P
= 0.003 and
P
22
One of the pivotal trials
showing benefit of AIs was the Arimidex, Tamoxifen, Alone or in
Combination (ATAC) trial, which compared anastrozole (1 mg)
with tamoxifen (20 mg), or their combination, given orally every
day for 5 years as adjuvant treatment for postmenopausal women
with early-stage breast cancer. After a median of 120 months, there
were significant improvements in the anastrozole group (but not
the combination group) compared with the tamoxifen group for
disease-free survival (hazard ratio [HR] 0.91, 95% CI 0.83-0.99;
p
= 0.04), time to recurrence (0.84, 0.75-0.93;
p
= 0.001), and time
23
to distant recurrence (0.87, 0.77-0.99;
The Trans-ATAC
trial evaluated the prognostic utility of RS in the 1231 treated on
p
= 0.03).
