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#266 - Brain Cancer Is Rapidly Increasing, 31-Dec-1991

Brain cancer is relatively rare, accounting for only 2% of all cancers,
but it seems to be increasing rapidly in children and in people over 65
in the U.S. The latest figures from the National Cancer Institute
indicate that brain cancer in the elderly (ages 75-84) is doubling
every 9 years [1, pg. 1621; 2, pg. 635.] In 1991 in the U.S., an
estimated 16,700 new cases of brain cancer were diagnosed and an
estimated 11,500 deaths occurred. [3, pgs. I.15-I.16] The causes of
brain cancer are unknown.

Brain cancer is usually fatal; the average (median) time between
diagnosis and death is about nine months. [1, pg. 1621.] The average
survival rate after 5 years is 25%, but in people over 65 the 5-year
survival rate is only 4%. [3, pg. I.16.]

This situation--a fatal cancer that is rapidly increasing, particularly
in older Americans--clearly sets the "cancer establishment" apart from
those younger medical professionals who are prevention-oriented.
"Cancer establishment" is a label commonly given to the tightly-knit,
international group of professionals that has controlled $2 billion per
year of research funds for the past 20 years as the U.S. has waged its
"war on cancer," searching unsuccessfully for a cure.

In 1988 when a group of prevention-oriented public health specialists
began to sound the alarm about rising cancer rates in older people in
many industrialized countries [2, 4], the cancer establishment attacked
them openly. Richard Doll, the eminent British epidemiologist, called
the new work "uninteresting," "quite uninformative," "boring," and "old
junk." [5, pg. 901.] As SCIENCE magazine said, "If it were politicians
doing this rather than scientists, you might say they were engaged in
spin control."

Doll's position, which he staked out in a paper first delivered in
September, 1989, is that deaths of older people that used to be
attributed to senility or some other non-specific cause are now
attributed correctly to cancers. [6, pg. 500.] Doll went on to make it
clear that he doesn't think cancer among older people is terribly
important anyway; he said "I conclude that we are, for the most part,
winning the fight against cancer. This does not appear from examination
of the trends in mortality [death] at all ages, but it does when we
examine the cohorts [groups] on whom the future depends." [6, pg. 508.]
In other words, Doll argues that the future does not depend on older
people so their rising cancer rates can be dismissed and we can declare
that we are winning the war on cancer.

A different view has emerged since the late 1980s among a group of
younger researchers who emphasize the need to prevent cancer rather
than cure it after it occurs. To them, rising cancer rates among older
Americans are a public health problem that needs to be understood and
prevented, not simply brushed aside. Two advocates of this position are
Devra Lee Davis of Mt. Sinai Medical Center in NYC and Joel Schwartz of
U.S. Environmental Protection Agency.

The latest information from the U.S. National Cancer Institute reveals
that the brain cancer problem is not confined to older people. A
"dramatic rise" in brain cancers has occurred during the last 15 years
in Americans over 65 but also in children, and in adults aged 30-34 [1,
pg. 1622.]

Between 1973 and 1985, the incidence (occurrence) of brain cancer
increased 2.6% per year in the age-group 0-4, 5% per year in the age-
group 30-34, 2.8% per year in the age-group 70-74, 7% per year in the
age-group 75-79, 20.4% per year in the age-group 80-84, and 23.4% per
year in those 85 and older. [1, pg. 1622.] Between 1973 and 1988, in
white children under age 14 in the U.S. the incidence of brain cancer
jumped from 2.3 per 100,000 to 3.4 per 100,000, a 47% increase in 15
years. [3, pg. II.32; 1, pg. 1622.] Data for non-white children is not
available.

In the age-group 75-84, brain cancer deaths increased 8% per year
between 1968 and 1983. Overall, brain cancer in Americans over 75
tripled between 1968 and 1983. [2, pg. 634.] Thus in older Americans,
brain cancer is doubling every 9 years, a very rapid increase. Even in
the age-group 30-34, deaths from brain cancer are doubling every 14
years.

Davis and Schwartz suggest that exposure to chemicals in the workplace
and in the general environment may explain the rise in brain cancer.
People over age 64 have experienced longer exposure to chemicals than
younger people, and in the past, they say, there were fewer
environmental and occupational controls. In addition, the proportion of
U.S. workers in blue collar jobs has declined steadily since the early
1960s. Furthermore, the production of synthetic [human created] organic
chemicals increased rapidly throughout the 1960s and 1970s and a rise
in cancers from exposure to these would be expected to be particularly
evident among the elderly. After careful analysis of available data,
Davis and Schwartz answer the Doll argument specifically: "There is no
evidence that recent increases in cancer mortality among elderly whites
in the U.S. chiefly reflect improved diagnoses in cases that would
formerly have been misrepresented or miscoded as ill-defined causes,
such as senility or non-specified cancers." [2, pg. 635.] They point
out that better diagnosis, aided by the CAT scan accounts for some of
the increase, but they also note the general increase began before CAT
scans grew common in the late 1970s.

The first suspicion of brain cancer risks in blue collar workers was
recorded in 1949 and definite evidence appeared in 1968 but it was not
until the 1980s that numerous studies revealed risks to rubber workers,
oil refinery workers, chemical plant workers, polyvinyl chloride
workers, and machinists (often exposed to various oils and oil mists).
Some white collar and professional occupations also have an elevated
risk of brain cancer including artists, laboratory professionals
(pathologists and hematologists, for example), veterinarians,
cosmetologists, farmers, and embalmers [7.]

Chemicals that have been implicated with brain cancer to one degree or
another include lubricating oil, acrylonitrile, vinyl chloride and
polyvinyl chloride (PVC), polycyclic aromatic hydrocarbons [PAHs], and
phenolic compounds [phenol, chlorophenols, cresol, resorcinol,
hydroquinone, and quinone], hexamethylenetetramine, coal tar, carbon
tetrachloride, methylene chloride, tetrachloroethylene, benzene,
toluene, PCBs, acrylates, acrylonitrile, diesel exhaust, welding fumes,
dyes, pigments, organochlorine pesticides, N-nitroso compounds, and
formaldehyde. [7] Other possible explanations, derived from study of
worker deaths include x-rays and electro-magnetic fields. [8, pg. 185;
7, pgs. 3,9.]

Workplace exposures cannot easily explain all brain cancers because
children never exposed to a workplace get brain cancer. Something
occurring during conception, during pregnancy, or shortly after birth
must cause brain cancer in young children. Some researchers wonder
whether it isn't chemicals affecting the father's sperm. Others wonder
whether it isn't electromagnetic radiation--the kind emanating from
large electric transformers at power substations, from the backs and
sides of many computer screens and TV sets, and from intimate contact
with electric blankets.

In addition to chemicals and electro-magnetic fields, exposure to
atomic radiation also contributes to brain cancer. Viruses, spontaneous
genetic aberrations, and perhaps other factors cause brain cancer as
well.

Until the U.S. and other industrial nations, which also appear to be
experiencing rising rates of brain cancer [9.], conduct more research
aimed at finding the causes of brain cancer, rates of incidence and
death seem likely to continue rising.

--Peter Montague

=====

[1] Nigel H. Greig, Lynn G. Ries, Rosemary Rancik, and Stanley I.
Rapoport. "Increasing Annual Incidence of Primary Malignant Tumors in
the Elderly," JOURNAL OF THE NATIONAL CANCER INSTITUTE, Vol. 82
(October 17, 1990), pgs. 1621-1624.

[2] Devra Lee Davis and Joel Schwartz, "Trends in Cancer Mortality: US
White Males and Females, 1968-83," THE LANCET Vol. I (March 19, 1988),
pgs. 633-636.

[3] Lynn A. Gloeckler Ries and others, CANCER STATISTICS REVIEW 1973-
1988 [National Institutes of Health Publication No. 91-2789]. Bethesda,
MD: National Cancer Institute, 1991.

[4] Devra Lee Davis, David Hoel, John Fox, and Alan Lopez,
"International Trends in Cancer Mortality in France, West Germany,
Italy, Japan, England and Wales, and the USA," THE LANCET Vol 366, No.
8713 (August 25, 1990), pgs. 474-481.

[5] Eliot Marshall, "Experts Clash Over Cancer Data," SCIENCE Vol 250
(Nov. 16, 1990), pgs. 900-902.

[6] Richard Doll, "Are We Winning the Fight Against Cancer? An
Epidemiological Assessment," EUROPEAN JOURNAL OF CANCER Vol. 26, No. 4
(1990), pgs. 500-508.

[7] Terry L. Thomas, and Richard J. Waxweiler, "Brain Tumors and
Occupational Risk Factors; A Review." SCANDINAVIAN JOURNAL OF WORK,
ENVIRONMENT AND HEALTH Vol. 12 (1986), pgs. 1-15.

[8] Anders Ahlbom, "Some Notes on Brain Tumor Epidemiology," in Devra
Lee Davis and David Hoel, editors, TRENDS IN CANCER MORTALITY IN
INDUSTRIAL COUNTRIES (New York: New York Academy of Sciences, 1990),
pgs. 179-190.

[9] Devra Lee Davis, Anders Ahlbom, David Hoel, and Constance Percy,
"Is Brain Cancer Mortality Increasing in Industrial Countries?"
AMERICAN JOURNAL OF INDUSTRIAL MEDICINE Vol. 19 (1991), pgs. 421-431.

Descriptor terms: brain cancer; cancer; us; industrialized countries;
health; carcinogens; chlorinated chemicals; prevention; elderly;
studies; workers; occupational safety and health; chemicals; childhood
cancer;