The US Food and Drug Administration issued a new warning on the drug
tamoxifen, advising doctors that it may cause an aggressivecancer of
theuterus.
The labelling of tamoxifen will be changed to add a "black box" warning about
the newly identified risk of uterine sarcoma,the drug agency said.
Black boxes are used to draw attention toproblems that are serious
and potentially lifethreatening.
Letters advising doctors of the new warning were sent out last month, but the
information was not posted on the agency's websiteuntil
Thursday.
Tamoxifen was already known to increase the risk of another, less dangerous
type of uterine cancer, endometrial adenocarcinoma,which is usually
detected at an early, curable stage. But therisk of the more
dangerous type of cancer had not been recognisedpreviously.
The new warning was directed only at women who have not had breast cancer but
are at high risk. The warning does not tellthose women to avoid
tamoxifen, but it does urge them to talkto their doctors about its
benefits and risks. The warning doesnot apply to women who have
already had breast cancer and whotake tamoxifen to prevent a
recurrence. For those women, the FDAsaid, the benefits far outweigh
itsrisks.
The warning is also aimed at women who have had a very early form of breast
cancer that is still confined to the milk ducts(ductal carcinoma in
situ, or DCIS). In those two groups, unlikethose who have had
invasive breast cancer, it has not been provedthat tamoxifen
prolongs life, even though it does lower the riskof breastcancer.
Uterine sarcoma is rare, estimated to occur in 0.17 women per 1000 a year who
take tamoxifen. In women not taking the drug,there are far fewer
casesonly 0.01 to
0.02 cases per 1000 women.Since 1978, when tamoxifen was first
marketed in the United States,159 cases of uterine sarcoma worldwide
have been reported in womentaking thedrug.
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"