The
information in this column is intended for informational
purposes only, and does not constitute medical advice or
recommendations by the author. Please consult with your
physician before making any lifestyle or medication changes, or if you
have any other concerns regarding your health.
BREAST
CANCER INCIDENCE
& HORMONE REPLACEMENT THERAPY
In
the years following the
end of World War II, the number of breast cancer cases diagnosed each
year
began to climb in the United States,
and they kept on climbing until, in
2003, a historic decline in the annual incidence of breast cancer
suddenly
appeared. One year
earlier, another
dramatic event related to breast cancer also occurred.
A huge prospective, randomized,
placebo-controlled hormone replacement therapy (HRT) clinical trial,
the
Women’s Health Initiative study, prematurely terminated the portion of
the
study evaluating combination HRT pills (the most common type of HRT
medication
prescribed throughout the world).
The
plug was pulled on this clinical study because a worrisome excess of
breast
cancers (as well as cases of cardiovascular disease) was observed among
the
women who were secretly randomized to receive HRT pills containing both
estrogen-like and progesterone-like female hormones (estrogen-only HRT
pills
are reserved for women who have previously undergone hysterectomy, as
this type
of HRT is associated with an increased risk of uterine cancer). The preliminary results of
this study’s
adverse findings, published in 2002 in the Journal
of the American Medical Association, identified a nearly 30
percent
increase in the risk of breast cancer among the women who had been
randomized
to take combination HRT pills.
Many
of us in the cancer research
and treatment community have been arguing, for decades, that the
continuously
rising incidence of breast cancer observed in the post-war United
States has been
due to, at least in part, the rising use of HRT medications. Even prior to the
publication of the Women’s
Health Initiative study’s adverse findings, there have been numerous
clinical
studies that have linked a woman’s lifetime exposure to female sex
hormones to
the risk of developing breast cancer.
In
fact, even decades-old epidemiological studies have, repeatedly,
identified an
early onset of menstrual periods and a late arrival of menopause as
risk
factors for breast cancer (these events mark the beginning and end of
ovarian
hormone production, respectively).
More
recently, large breast cancer prevention studies have confirmed that
estrogen-blocking medications can reduce the risk of breast cancer by
about 50
percent in women who are at high risk for this type of cancer.
However,
despite decades of clinical
and scientific evidence linking HRT to breast cancer risk, it took the
sobering
results of the Women’s Health Initiative study to finally convince
large
numbers of women, and their physicians, that HRT increases the risk of
breast
cancer (and, contrary to the findings of less rigorous and much older
epidemiological studies suggesting that HRT reduces the risk of
cardiovascular
disease in women, the opposite effect actually appears to be the case). Following widespread
reporting of the
negative findings of the Women’s Health Initiative study, new HRT
prescriptions
in the United States
declined an average of 40 percent over the first three years following
the
publication of the study’s results.
Several
clinical studies over
the past 5 years have compared HRT prescribing trends with the
incidence of
breast cancer in the United States.
These studies have shown a significant decrease in the
number of new HRT
prescriptions filled each year since 2002, and when plotted on a graph,
the curve
of this decline in new HRT prescriptions matches up very nicely with
the curve
of the declining number of new breast cancer cases observed each year
since
2003. And yet, a
significant number of
doubters still remain. Some
have
hypothesized that a small downturn in the number of women undergoing
screening
mammograms might explain the fewer cases of breast cancer that have
been
diagnosed each year since 2003. Others
have come up with even less likely potential explanations, hoping to
explain
away the growing and already substantial research evidence linking HRT
with an
increased risk of breast cancer.
However, two new breast cancer research updates further
confirm the link
between HRT and breast cancer risk.
An
update of a previous
breast cancer incidence study, from the National Cancer Institute and
the M.D.
Anderson Cancer Center,
has just been published online in the journal Breast
Cancer Research & Treatment.
In this study, the authors reviewed and
analyzed the newly updated SEER (Surveillance Epidemiology &
End Results)
database, which is the national cancer statistics database maintained
by the
National Cancer Institute.
When
compared to the period
between 2000 and 2002, significant declines in the number of new cases
of
breast cancer were observed between 2003 and 2005.
Altogether, a 20 percent drop in the
incidence of new breast cancer cases was observed during the period
beginning
in 2003 and ending in 2005, and this historic trend closely mirrors the
results
predicted by the 2002 Women’s Health Initiative study report. Moreover, nearly the
entire decline in breast
cancer cases was observed in postmenopausal women over the age of 50,
and in
breast cancers sensitive to estrogen, further linking this dramatic
decrease in
breast cancer incidence to decreased HRT use among women.
The
other dramatic breast
cancer research update was announced at the world’s largest annual
breast
cancer research conference, the San Antonio Breast Cancer Symposium,
less than
two weeks ago. At
this symposium, the researchers
from the Women’s Health Initiative study provided an update on the
women who
participated in the combination HRT group.
These updated results offer striking proof that
combination HRT pills
are associated with a significantly increased risk of developing breast
cancer. Among the
study volunteers who
took combination HRT pills for an average of 5 years, their risk of
breast cancer
is now 100 percent greater than what is being observed among the women
volunteers who were secretly randomized to receive identical placebo
(sugar)
pills. This means
that the incidence of
breast cancer among the women who received combination HRT pills is now
fully
twice as high as is being observed in the women who did not take HRT
pills.
I
have, for almost two decades
now, recommended against taking HRT medications.
In 85 to 90 percent of women, the symptoms of
menopause subside significantly within 2 to 3 years.
Although they are not quite as effective as
HRT drugs in relieving the symptoms of menopause, there are also a
variety of
prescription and non-prescription remedies available that can reduce
the
severity of the hot flashes, night sweats and irritability that often
accompany
the early phases of menopause. (I
will
have much more to say on the topic of breast cancer prevention in my
forthcoming book, “A Cancer Prevention Guide for the Human Race.”) Today, in 2008, my
recommendations against
HRT drugs remain even more vigorous than ever before.
CIRCUMCISION
& THE RISK OF HPV & HIV INFECTION
Male
circumcision continues
to be a hotly debated topic. The
practice of circumcision, most commonly performed for religious or
cultural
reasons, has been ongoing for thousands of years.
Recently, however, there has been a growing
backlash against infant circumcision in the United States and, in
fact, between 1971 and 1983, the American Academy of
Pediatrics formally advocated
against the practice. The
Academy’s
position against circumcision was modified in 1989, however, after new
clinical
research data was published suggesting that circumcision significantly
decreased the risk of acquiring the human immunodeficiency virus (HIV). However, in view of the
historically
non-medical basis for circumcision, and due to an increasing
sensitivity on the
part of both parents and physicians towards the discomfort that infants
may experience
during circumcision, this procedure continues to be the subject of
considerable
debate.
Three
newly published studies
in the Journal of Infectious Diseases
add to the findings of previous studies suggesting that a potential
clinical
benefit may be associated with circumcision.
Specifically, these new studies suggest that not only does
male
circumcision reduce the risk of acquiring HIV infection, but it may
also
significantly reduce the risk of infection with the human papilloma
virus
(HPV). Like HIV,
HPV is a sexually
transmitted virus, and several strains of the HPV virus are known to
cause
virtually all cases of cancer of the cervix in women, as well as many
of the cases
of cancers of the anal canal, oral cavity, and throat (in both men and
women). Several HPV
virus strains also cause genital
warts in both men and women.
While
chronic infection with
cancer-causing HPV strains produces precancerous changes in women that
can
usually be detected during Pap smears, most infected males are
asymptomatic. The
FDA recently approved
a human HPV vaccine, Gardasil, which provides protection against 4
strains of
the HPV virus. Although
not all cancer-causing
strains of HPV are covered by Gardasil, the vaccine does provide
protection
against the HPV strains that, together, account for about 70 percent of
all
cervical cancer cases, and against more than 90 percent of all
HPV-associated
cases of genital warts. Because
the
vaccine is quite expensive, and because the vast majority of cancers
caused by
HPV occur in women, Gardasil is approved for use only in girls and
young women
between the ages of 9 and 26 years.
The
three new studies
presented in the Journal of Infectious
Diseases compared the incidence of HPV and HIV infections in
sexually
active men with and without a prior history of circumcision. One of these studies
prospectively assessed
the effects of adult circumcision in young African men, and after 21
months of
follow-up, the incidence of HPV infection was observed to be 34 percent
lower
in the men who had been randomized to undergo circumcision when
compared to the
men who did not draw the “circumcision card.”
The second clinical study was performed in the United States,
and evaluated the incidence of HPV infection among circumcised and
uncircumcised men. Among
the 16 percent
of men who had previously been circumcised, the incidence of HPV
infection,
after adjusting for a number of behavioral and demographic variables,
the
authors of this second study identified a 53 percent lower risk of HPV
infection in the circumcised men when compared to the uncircumcised men.
In
an accompanying editorial,
both of these studies were criticized due to inherent weaknesses in
both
methodology and analysis, although the editor acknowledged that there
may well
be a protective effect of circumcision against HPV infection in males. As males act as both
reservoirs and vectors
in the transmission of HPV, the possibility that circumcision may
decrease the
incidence of HPV infection in men is intriguing.
As prior studies have produced conflicting
results regarding the protective effect, if any, of circumcision
against HPV
infection in men, we must await the results of two large prospective
male
circumcision trials ongoing in Africa
before
circumcision can be advocated for the purpose of reducing the incidence
of HPV
infections.
A
third study in the Journal of Infectious
Diseases adds to
the already substantial body of research data confirming that male
circumcision
decreases the risk of HIV infection.
In
this third study, also performed in Africa,
male circumcision reduced the risk of HIV infection in heterosexual
African
males known to be exposed to the virus by almost 50 percent, which is
comparable to the findings of multiple prior studies that have looked
at the
impact of circumcision on HIV infection risk.
Taken
together, these three
studies add important information regarding the potential protective
effects of
circumcision against infections by the HPV and HIV viruses. While the jury is still
out with respect to
circumcision and the risk of HPV infection, the data showing that
circumcision
cuts the risk of HIV infection in half is quite robust.
Because of these findings, the World Health
Organization now advocates on behalf of male circumcision as part of a
comprehensive strategy to prevent HIV infections.
However, no research study has ever suggested
that male circumcision can protect men (or women) against all cases of HIV infection, and so even
if you are circumcised, you
still need to adhere to established safe sex practices to protect
yourself and
your partner from infections with HIV, HPV and other sexually
transmitted
diseases.
Disclaimer:
As always, my advice to readers is to seek the advice of your physician
before making any significant changes
in
medications, diet, or level of physical activity.
