Doubling Time on Tamoxifen Cuts Odds for Breast Cancer's Return: Study06/02/13
SUNDAY, June 2 (HealthDay News) -- When it comes to using the
drug tamoxifen to prevent breast cancer's return, longer may be
better for some patients, a new study finds.
Women combating estrogen-sensitive breast tumors fared better
when treated with 10 years of tamoxifen compared to those given the
current standard of five years, researchers found.
However, longer tamoxifen regimens were associated with a
greater risk for side effects from the cancer-suppressing drug,
such as night sweats, hot flashes, blood clots, strokes and a
heightened risk for cancer of the lining of the uterus (endometrial
Still, the investigation found that 10 years of treatment gave
patients better protection against the recurrence of estrogen
receptor (ER)-positive breast cancers and/or death than did
treatments offered for half as long.
Assessing the findings in conjunction with the results of
another recently completed study called the ATLAS trial, the team
concluded that the benefits of prolonged therapy still outweigh any
The study was scheduled for presentation Sunday in Chicago at
the annual meeting of the American Society of Clinical Oncology
Five years of tamoxifen "is already an excellent treatment but
we thought that longer treatment might be even better because women
with ER-positive breast cancer can have recurrences long after
treatment is completed," study lead author Richard Gray, professor
of medical statistics at the University of Oxford in the United
Kingdom, said in an ASCO news release.
"Until now, though, there have been doubts whether continuing tamoxifen beyond five years is worthwhile," he added. "This study and its international counterpart ATLAS confirm that there is definitely a survival benefit from longer tamoxifen treatment and many doctors will likely recommend continuing tamoxifen for an extra five years."
The research was funded by Cancer Research UK and the UK Medical
Research Council. Findings presented at medical meetings are
typically considered preliminary until published in a peer-reviewed
The study involved nearly 5,000 British breast cancer patients,
all of whom had already completed a five-year regimen of tamoxifen
by the time they entered the study at some point between 1991 and
In turn, half the women were randomly assigned to continue the
medication for another five years, while half stopped the treatment
The result: no appreciable difference was found in death or
breast cancer recurrence when assessing the impact of the sixth to
ninth years of continued treatment.
However, when looking long-term -- at the 10th year and beyond
-- the team found that the longer treatment option was having an
impact. For example, breast cancer recurrence was lower among the
10-year group than the five-year group, at 16.7 percent versus 19.3
What's more, continuing treatment for double the usual period
also reduced the overall risk of dying from breast cancer, the team
"These results are therefore practice-changing for premenopausal women with hormone receptor-positive breast cancer and especially relevant for women who are at high risk of recurrence," Dr. Sylvia Adams, an ASCO spokesperson and breast cancer expert, said in the ASCO news release.
There's more on estrogen and cancers at the
U.S. National Cancer Institute.
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