colon-cancer death rates
People who regularly take aspirin cut in half their risk of dying from colon cancer, according to the largest, most
definitive epidemiologic study to investigate this link. The finding suggests
a relatively inexpensive strategy for battling a scourge that currently claims the lives of about 50,000 Americans annually.
The new work also adds weight to the findings of a much smaller study reported earlier this year. Although that retrospective study of about 6,000 men and women did not address cancer-survival rates,
it did indicate that regular aspirin use may reduce the incidence of colon cancer (SN: 3/16/91, p.166).
Spurred by those findings, epidemiologist Michael J. Thun and his colleagues at the American Cancer Society in
Atlanta correlated aspirin use and colon-cancer deaths among the 662,424 men and women they had been tracking since 1982 as
part of the society’s Cancer Prevention Study. Upon entering the study
participants had answered a questionnaire covering a range of behavioral, dietary and lifestyle factors, including
frequency of aspirin use during the past year.
The risk of dying from colon cancer decreased with increasing aspirin use, Thun’s team reports
in the Dec. 5 NEW ENGLAND JOURNAL OF MEDICINE. Colon-cancer death rates among the most frequent users—-those taking aspirin 16 times or more per month—were 60 percent as high as that seen in the study’s aspirin abstainers. And when the researchers controlled for risk factors such as diet, obesity and
family history of colon cancer, the risk dropped to 50 percent of the colon-cancer death rate of the aspirin abstainers.
“It’s an interesting finding,” says epidemiologist John A. Baron of Dartmouth Medical School
in Hanover, N.H. He notes, however, that the new study does not prove that aspirin
itself helps prevent colon cancer. For examp1e, he points out that side effects
of frequent aspirin use, such as Intestinal bleeding may have caused members of this subgroup to seek medical attention more
frequently than other volunteers thereby increasing the likelihood that any developing colon cancer would receive early
diagnosis. And early diagnosis increases the chance that a person with colon
cancer will survive.
A large, randomized trial in which some people take aspirin and others take placebo pills would provide firmer evidence
of aspirin’s protection against colon cancer. But such a gold-standard
study might be difficult to conduct, Baron says, because people who know about aspirin’s widely publicized heart benefits
(SN: 7/27/91, p.55) might balk at the prospect of receiving placebo pills instead.
For now, Baron and Thun remain cautious about advocating regular aspirin use for cancer
prevention, since it can cause potentially dangerous side effects.** At
the same time, they note that aspirin may provide secondary anticancer benefits for people who already take it to manage
arthritis pain or to reduce the risk of heart disease.
Even if epidemiologists can demonstrate that aspirin fights colon cancer, there remains the question
of how it exerts this effect. Like other nonsteroidal anti-inflammatory drugs
(NSAIDs), aspirin inhibits the synthesis of compounds called prostaglandins, which spur body cells — including colon cells — to proliferate.
Thun suggests that aspirin might prevent rampant cell division —
a key attribute of cancers —
by interfering win prostaglandin production.
A number of laboratory studies have shown that aspirin and other types NSAIDs inhibit the growth of
chemical induced colon tumors in rats and mice. Other studies have shown that
an NSAI called sulindac can shrink large-bow polyps in people. Such polyps, though
benign, can develop into cancers, Thun notes. Taken together, the individual
pieces of evidence provide scientists wit compelling reasons to further explore the link between aspirin and colon cancer,
Thun contends. — KA. Fackelman,
Science News, 1994, p. 374.***
* Two other problems, is first that it is easy because of taste
to identify aspirin. Second, the just prior mentioned objection of early medical
attention would still be a contravening variable. However, if the study also
recorded those who were diagnosed with color cancer this objection would be laid to rest.
In fact in the afore mentioned study of 662,424 participants recorded colon cancer, this objection would be laid to
** This problem as well as the identification of the placebo
are laid to rest with the use of enteric (coated aspirin), for it digests in the intestines, which is alkaline. Since aspirin is a weak acid, its acidity is neutralized, and thus as is to be expected the enteric aspirin
does not cause stomach bleeding—and there is little risk of intestinal bleeding.
*** Subsequent studies have confirmed this prophylactic result and
the science behind it.
A PREEMPTIVE STRIKE AGAINST CANCER, Aspirin cuts risks gives
a big boost to a slew of promising drugs
DRUG COMPANIES ARE pouring billions of dollars into developing new targeted therapies for cancer, and so far none are close to a cure.
But there is a countervailing force to their quest: the search for widely available drugs that could stop cancer from starting.
Chemoprevention, as the field is called, just got a win with the news that aspirin, already used to prevent heart disease,
reduces the risk of the most common form of breast cancer.
one is ready to recommend that women start popping aspirin every day, in part because the drug can cause gastrointestinal
side effects. But the report, in the May 26 issue of The Journal of the American Medical Association, does raise the
hope that women already taking aspirin to prevent heart disease may be getting another valuable benefit. “I think this
is a very important paper,” says Dr. Waun Ki Hong, a pioneer in chemoprevention at the M.D. Anderson Cancer Center
Hong says a number of drugs have now been shown to suppress cancer, including aspirin and similar nonsteroidal anti-inflammatory
drugs (NSAID5) such as ibuprofin. In fact, aspirin
has already been proven effective in preventing colon cancer. A stream of studies
over the last few yeas has also focused on aspirin’s potential against breast cancer, but with mixed results. The JAMA study by researchers from Columbia University, is noteworthy because it shows which type of breast
cancer would most likely be prevented—and why.
DOWNSIDE TO DAILY DOSES
THE RESEARCHERS studied 3,000 Long Island women, half with breast cancer and half without, and analyzed how often they
took aspirin, ibuprofen (such as Advil), and acetaminophen (such as Tylenol). They found that 20.9% of the women with breast
cancer had taken aspirin regularly for six months or longer before they were diagnosed, compared with 24.3% of the women in the control group. That adds up to a 20% lower risk of breast
cancer for aspirin users vs. nonusers. The drug was most effective
against tumors that are
dependent* on the hormones estrogen and progesterone, reducing the risk of these types of cancers by 26%. Hormone-dependent
tumors account for 60% to 70% of all breast cancer
cases. Ibuprofen had a weaker effect, while acetaminophen, which is not an NSAID, offered no protection.
The Columbia scientists based their study on 10 years of lab research. They knew that aspirin blocks an enzyme in the
blood called COX-2 that stimulates estrogen production. Testing its effect in mice, Dr. Andrew J. Dannenberg of Weill-Cornell Medical College, a co-author of the JAMA report, found that aspirin reduced both estrogen and breast
cancer experts say the Columbia study wasn’t flawless. It only followed the women for a year, and was retrospective—the
outcomes were based on participants’ reports of their own behavior and open to bias, a problem with many such studies.
But more money is being poured into prospective trials, which give a drug to a large population over a number of years to
see what happens. The National Cancer Institute is conducting a seven-year trial with 22,000 women to see whether tamoxifen,
a breast cancer treatment, or Eli Lilly & Co.’s Evista, an osteoporosis drug, is better able to prevent breast
cancer. Results are due in 2006.
The NCI says there are more than 40 other drugs
in chemoprevention trials, ranging from old standbys like aspirin to new targeted therapies such as AstraZeneca PLC’S Iressa, a lung cancer treatment approved in 2003. M.D.
Anderson doctors are testing Iressa and Tarceva, a similar drug by Genentech and OS1 Pharmaceuticals, in heavy smokers
in an attempt to prevent lung cancer.
There can be a downside to giving a pill every day to prevent disease. Merck & Co.’s anti-baldness
drug, Proscar, was able in a large trial reported
last year to reduce prostate cancer by 25%, but the men on Proscar who did develop cancer tended to get more deadly tumors,
possibly because of the drug.
cancer specialists are encouraged. “Oncology is two decades behind cardiology when it comes to disease prevention,
but we are beginning to get smarter about it,” says Dannenberg. The 212,000 women likely to be diagnosed with breast
cancer in the U.S. this year can only hope so.
-By Catherine Arnst in New York
PAGE 48, Business Week ; June7, 2004
*THE CANCER IS NOT DEPENDENT ON ESTROGEN
OR PROSTOGLANDINS, BUT RATHER HAS ON THE SURFACE OF THOSE CELLS RECEPTORS FOR ESTROGEN.
WHEN STIMULATED BY ESTRONGEN THEY DIVIDE MORE RAPIDLY. THUS A LIFE THREATENING
BREAST CANCER (link to explanation of how cancer becomes life threatening) WILL GROW AND SPREAD FASTER. IN OTHER WORDS, THE CLOCK HAS
BEEN PUSHED FORWARD FOR THOSE WITH THE RIGHT SET OF MUTATIONS. Thus the results are suspect. In long-term estrogen studies,
after a moderate first couple of year surge, breast cancer rates for those on estrogen fell slightly below the control group
and the two became essentially equal. . For an account of the poor media work on hormone replacement therapy (HRT). --JK
ASPIRIN SHOWN TO PREVENT PREGNANCY-INDUCED HYPERTENSIVE DISEASE
The recent meta-analysis of aspirin and pregnancy-induced
hypertension by Imperiale and Petrulis caught our interest, and we examined this issue from the standpoint of clinical decision
making. Since the meta-analysis included studies that were not randomized, not
blinded, or used dipyridamole in addition to aspirin, we excluded data from those studies.
Using data from the remaining studies that addressed cesarean sections, we found that 5.6% of the aspirin group required
cesarean sections, compared with 23.9% of the control group. The maximum aspirin
costs is $4.60 and the cost difference between cesarean and vaginal birth of $3,014.
Calculating 5.6% c-section plus the cost of aspirin yields $173 per patient, for those without aspirin, 23.9%
News, Dec. 11, 1991, Vol. 266 No. 22
companies are about making a profit. Medicinally valuable substances that are
not profitable such as aspirin are not pushed by drug companies. Information
about, for example, about aspirin’s other uses generally are not widely known.
Moreover, the drug companies in seeking to promote their expensive alternative to aspirin, state that their product
is better. They create expectations in the public who then expect something for
arthritis other than aspirin, such as Naproxin. Doctors to please their
patients and often because of being mislead by the advertisements of drug companies proscribe the more expensive alternatives. Harm is done by taking a substance that is not as safe and has not been shown to have
the other beneficial qualities, the reduction of colon cancer by 50%.
companies should not be allowed to exert influence upon the research of the products they are having tested in hopes of getting
FDA approval for, nor should they be given control of the information (research results).