It has long been known that drinking alcohol can increase a
woman’s risk of breast cancer. A recent review from the French International Agency for Research in Cancer looked at 15 meta-analyses
on the risk relationship between alcohol consumption (including light
consumption) and the risk of breast cancer. (A meta-analysis is a
statistical approach to combine the results from multiple studies in an effort
to improve estimates of the size of an effect and/or to resolve uncertainty
when reports disagree.) All but
two of these analyses showed a dose-response relationship between alcohol
consumption and the risk of breast cancer, even at low levels of consumption.
Researchers at the University of
Houston have found a cancer-causing gene that is triggered by alcohol. Cancer biologist Chin-Yo Lin says: "Our research shows alcohol enhances the
actions of estrogen in driving the growth of breast cancer cells and diminishes
the effects of the cancer drug Tamoxifen on blocking estrogen by increasing the
levels of a cancer-causing gene called BRAF." Along with colleagues, he
published his findings in PLOS ONE, an open access, peer-reviewed
scientific journal published by the Public
Library of Science. The authors estimate that tens of thousands of breast
cancer cases in the U.S. and Europe each year are attributable to alcohol
consumption and that drinking is also associated with an increased risk of
disease recurrence in women with early stage breast cancer. Another key finding was that alcohol
weakened Tamoxifen's ability to suppress the rapid growth of cancer cells. Lin
and his colleagues posit that their results suggest exposure to alcohol may
affect a number of cancer-related pathways and mechanisms. He says their
findings have implications for women who are undergoing hormone replacement
therapy for menopausal symptoms, as alcohol can affect the actions of the
hormones they take to manage their symptoms. The research highlights potential
long-term health effects for college-age women, who might find themselves in
situations where heavy or binge drinking is part of the social environment.
"We hope these and
future findings will provide information and motivation to promote healthy
behavioral choices, as well as potential targets for chemoprevention strategies
to ultimately decrease breast cancer incidents and deaths within the next
decade," Lin said. "We want to provide women, in general, with more
information and insight to be better able to balance their consumption of
alcoholic beverages with the potential health risks, including cancer patients
who may want to take into consideration the potential detrimental effects
alcohol consumption might have on treatments and modify their behavior and
habits accordingly."
Alcohol may affect the
growth of cancers beyond the breast. A recent study from the University of
Otago in New Zealand was published in the journal Addiction; it was also based on meta-analyses concerning alcohol
and a variety of cancers. The
author wrote ”even without complete knowledge of biological mechanisms, the
epidemiological evidence can support the judgement that alcohol causes cancer
of the oropharynx, larynx, oesophagus, liver, colon, rectum and breast. The measured associations
exhibit gradients of effect that are biologically plausible, and there is some
evidence of reversibility of risk in laryngeal, pharyngeal and liver cancers
when consumption ceases. The limitations of cohort studies mean that the true
effects may be somewhat weaker or stronger than estimated currently, but are
unlikely to be qualitatively different.”
How can we wisely react to these
recent findings? Alcohol has been
a part of the human experience since our early beginnings. Many other factors
are closely related to the development of cancer, such as ionizing radiation,
tobacco, the papilloma virus, UV exposure, family genetics, environmental
toxins, unhealthy diets et al.
Cancer incidence rises with age, along with DNA changes in our
genome. Alcohol is clearly not the
only risk factor for cancer, but it is one we can control. I think it is wise for women to be very
careful about alcohol use, not to exceed one drink a day, and preferably use
less, such as a drink only on special occasions. Women dealing with breast cancer should stop
altogether. Men who drink daily
should limit their intake to one or two drinks at most. If there is a strong
family history of colon cancer or other cancers, stop completely. If you are diagnosed with cancer, stop
completely. Go to AA
meetings. If you don’t believe in
a God, try nature or your sober friends for support. My partner used to say ”I need an attitude adjustment”
before having a glass of wine. Now
he says “Let’s meditate”.
Sadja Greenwood, MD, MPH
