Adjuvant endocrine therapy (ATE) - hormone-blocking drugs such as
tamoxifen or aromatase inhibitors that can lower the odds of cancer
coming back - is associated with a 29% reduction in the risk of
death for women with hormone-receptor-positive breast cancer.
A nationwide cancer registry of almost one million patients treated
for hormone-sensitive breast cancer shows that one out of six women who
should have received this post-surgical treatment did not get this recommended component of care.
‘One out of six women with hormone-sensitive breast cancer who should have received post-surgical treatment with adjuvant endocrine therapy did not get this recommended component of care.’
authors estimate that 14,630 women who did not get hormone treatment
died unnecessarily between 2004 and 2013 from recurrence of their
Adherence to the guidelines for AET after surgery slowly improved
over the period studied. By the end of the study, however, 18% of
women who could have benefited were still not getting potentially
life-saving care. The researchers also found that about 3% of
women who lacked hormone receptors were inappropriately treated with
"The use of adjuvant endocrine therapy slowly gained popularity over
this time," said study senior author Dezheng Huo, associate
professor of public health sciences at the University of Chicago. "It
improved after 2004, rising from 70% in 2004 to almost 84%
in 2011. Then it declined slightly to 82% in 2013, when the
"Our results suggest that it is still underused," Huo said, "and in
some cases, misused, offered to patients who lack hormone receptors."
The study, published in JAMA Oncology
data from the National Cancer Data Base (NCDB), which is supported by
the American College of Surgeons and the American Cancer Society. The
NCDB collects information about cancer patients, treatments and outcomes
from more than 1,500 accredited healthcare facilities.
The authors found data from more than two million patients who were
diagnosed with breast cancer between 2004 and 2013. They narrowed that
down to women at least 18 years old who had stage-1, 2 or 3 breast
cancer, treated with lumpectomy or mastectomy, usually followed by
radiation and, less often, chemotherapy. The women had to express
estrogen or progesterone receptors. They wound up with records from
818,435 patients, who met the criteria and were likely to benefit.
AET slows or stops the growth of tumors that feed on these hormones.
Drugs such as tamoxifen, for example, attach to the estrogen receptor
in a cancer cell and shut down the hormone's cancer-causing effects.
Patients are encouraged to take the pills, one a day, for 10 years or
Compliance with AET guidelines in this study varied from hospital to
hospital. The researchers selected 80% compliance with the
guidelines as a reasonable goal for individual hospitals. They found
that in 2004, only 40% of hospitals met that standard. By 2013,
almost 70% of hospitals were reaching the 80% standard.
"Still, 30% of hospitals were falling short," Huo said.
Several factors influence compliance. Hormone therapy does have side
effects, such as hot flashes or nausea. Patients taking tamoxifen have
an increased risk of stroke. Those taking aromatase inhibitors have an
increased risk of osteoporosis.
Since there is no immediately detectable benefit from AET, some
breast cancer patients choose not to take hormone therapy. Others begin
therapy but lapse over time. Smaller studies found that 30 to 70%
of patients discontinue AET within five years.
Patients treated with surgery followed by radiation or chemotherapy
were more likely to stick with AET. Women treated at larger hospitals,
with 400 beds or more, were more compliant.
There were also racial disparities. Black and Hispanic women are
less likely than non-Hispanic whites to receive AET. Asian women are
more likely to receive AET.
Hospitals in certain geographic regions had better success. Those in
New England and the upper Midwest achieved compliance rates seven to 12% higher than those in the South and West.
The authors stress that their data has limitations. Previous studies
suggest that adjuvant endocrine therapy may be under-reported, in some
cases by as much as 10%.
On the whole, however, the researchers note that although AET use
has been steadily increasing. optimal usage, according to Huo, "has not
been achieved." Because of these gaps, "certain women are being deprived
of this life-saving therapy."