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CANCER TRENDS
U.S. cancer trends are increasingly bleak. There are two ways to
judge cancer trends: by incidence rates and by death rates.
Cancer incidence refers to the number of new cases of cancer per
100,000 population, age-adjusted.  Similarly, the cancer death
rate is the number of cancer deaths per 100,000 population,
age-adjusted.  The purpose of adjusting for age is to eliminate
trends that might occur simply because the average age of the
population is increasing.  In other words, age-adjusting
eliminates the argument, "Cancer only SEEMS to be getting worse
because people are living longer."
Table 1 presents the latest U.S. cancer statistics from the
National Cancer Institute, covering the period 1950 to 1992 (the
last year for which published data are available).[1]  As the
table makes clear, there are four cancers for which the news is
entirely good: both incidence and deaths are declining (cervix,
stomach, rectum, and uterus).
There are also eight cancers for which the news is mixed:
incidence is increasing while deaths are declining.  These
cancers are striking a larger proportion of Americans each year,
yet surgery, chemotherapy, and radiation treatments are keeping
more victims alive.  These are the eight cancers that more people
are having to learn to live with: cancers of the colon, larynx,
testicles, bladder, and thyroid, Hodgkin's disease, leukemias,
and all childhood cancers.
Then there are 11 cancers for which the news is all bad:
incidence is rising, and so is the death rate.  These 11 are:
cancers of the ovaries, lung, skin, female breast, prostate,
kidney, liver, non-Hodgkin's lymphomas, multiple myeloma, brain,
and pancreas.
In the U.S., the incidence of all cancers has increased 54.3%
during the past 45 years, and the death rate for all cancers has
increased 9.6%. However, lung cancer --which is caused mainly by
cigarettes --dominates these increases.  If lung cancer is
excluded, the incidence of all cancers has still increased an
impressive 40.8% during the past 45 years, but the death rate has
declined 15.0% during the same period. This shows rather
dramatically the extent to which more of us each year are
"learning to live with cancer."
A recent review article by the staff of the National Cancer
Institute (NCI) adds some perspective to these numbers.[2]  Among
men, prostate cancers account for two-thirds of the cancer
incidence increase during the past 20 years.  Notable increases
have also occurred in non-Hodgkin's lymphomas and skin cancers
(melanomas).
Among women, the major increases of the past 20 years occurred in
cancers of the breast and lung, followed by non-Hodgkin's
lymphomas and skin melanomas.
The NCI analysts found that, in general, the rising incidence of
cancers in the U.S. is dominated by increases at older ages in
breast, prostate, and lung.
Regarding breast cancer, the NCI analysts say that some, though
not all, of the increase is accounted for by earlier detection.
They point out that the biggest increase has occurred among
estrogen-responsive tumors --that is to say, the kind of breast
cancer that is increasing most rapidly is the kind that is
influenced by the presence of estrogen, "suggesting that some of
the changes are related to hormonal factors," the NCI analysts
say.
Among men the biggest increase is found in prostate cancer
--another cancer influenced by hormones.  The NCI analysts say
better diagnosis accounts for part, but not all, of the increase.
They conclude, "it is possible that nutritional practices (e.g.,
increased consumption of fat and meat) have contributed to the
upward trend."
These data hide significant differences between races. The
highest incidence of cancer in the U.S. occurs among black men
(557.2 cases per year among each 100,000 persons), followed by
white men (464.0), then white women (348.0), then black women
(331.8).
The incidence of colon cancer is 20% higher among blacks than
among whites.[3]  The incidence of multiple myeloma is about 50%
higher among blacks than among whites, and the incidence of
prostate cancer is 71% higher among blacks.  (Multiple myeloma is
cancer of the immune system's cells in the bone marrow.) Lung
cancer --caused mainly by cigarette smoking --is 36% higher among
blacks than among whites.[4]
Relative survival rates are poorer among blacks then among
whites; generally, about 75% as many blacks as whites survive a
particular cancer.  Survival rates are thought to reflect
socio-economic status. Thirty percent of blacks live in poverty
vs. only 13% of whites.[4] Among blacks cancer tends to be at an
advanced stage when it is first detected, compared to whites,
which partially explains why black survival rates are poorer.
Much cancer is caused by "environmental factors," broadly defined
to include food, drink, and habits such as smoking tobacco and
basking in the sun.
Numerous studies have shown that environmental factors are far
more important than genetic, inherited factors.  Cancer rates
differ from country to country.  When people migrate from one
country to another, within a generation or two their cancer rates
have changed from those of their country of origin to those of
their new homeland.  For example, Japanese women living in Japan
have a low rate of breast cancer; but Japanese women who move to
the U.S. soon have U.S. rates of breast cancer.
These "migration studies" --of which there are now many in the
literature[5] --tell us that many cancers are preventable.
Unfortunately, there is a great deal of money to be made treating
cancer, and little money to be made preventing cancer.  And so
cancer prevention today gets about one penny out of every dollar
spent on cancer research.
So long as we continue to bathe ourselves in carcinogens in air,
water, and food, and in chemicals that degrade our immune
systems, more of us each passing year will have to learn to live
with cancer.  Present policies are exceedingly expensive
(estimated at $72.5 billion in 1985) and don't make much sense
from a public health viewpoint, but they make eminently good
sense from the viewpoint of the cancer industry --those who cause
it and those who sell services that ameliorate its effects. The
cancer industry is robust and healthy; by comparison, the
proponents of prevention are sickly, weak and pallid.
						--Peter Montague
		(National Writers Union, UAW Local 1981/AFL-CIO)
===============
[1] Source: C.L. Kosary and others, editors, SEER CANCER
STATISTICS REVIEW 1973-1992 [National Institutes of Health
Publication No. 96-2789] (Bethesda, Md.: National Cancer
Institute, 1995), Table I-3, pg. 17. NIH says historical data for
non-whites are not considered reliable spanning the period
1950-1992 so historical data are only given for whites.
[2] Susan S. Devesa and others, "Recent Cancer Trends in the
United States," JOURNAL OF THE NATIONAL CANCER INSTITUTE Vol. 87,
No. 3 (February 1, 1995), pgs. 175-182.
[3] Lynn A. Gloeckler Ries and others, "Cancer incidence,
mortality, and patient survival in the United States," in David
Schottenfeld and Joseph F. Fraumeni, Jr., editors, CANCER
EPIDEMIOLOGY AND PREVENTION [SECOND EDITION] (New York: Oxford
University Press, 1996), pgs. 168-191.
[4] John W. Horm and others, "Cancer incidence, mortality, and
survival among racial and ethnic minority groups in the United
States," in David Schottenfeld and Joseph F. Fraumeni, Jr.,
editors, CANCER EPIDEMIOLOGY AND PREVENTION [SECOND EDITION] (New
York: Oxford University Press, 1996), pgs. 192-235.
[5] David B. Thomas and Margaret K. Karagas, "Migrant studies,"
in David Schottenfeld and Joseph F. Fraumeni, Jr., editors,
CANCER EPIDEMIOLOGY AND PREVENTION [SECOND EDITION] (New York:
Oxford University Press, 1996), pgs. 236-254.
=================================================================
			TABLE 1
U.S. Cancer Incidence and Deaths in 1992, and the Percent Change
in Age-Adjusted Rates of Incidence and Death per 100,000 U.S.
Population, 1950-1992.
.
.		-----ALL RACES-------    ------WHITES---------
Cancer	   Incidence      Deaths       Percent    Percent
type	       in 1992     in 1992     change in  change in
.	      (estimated)		incidence,     deaths,
.					  1950-1992   1950-1992
----------------------------------------------------------------
stomach	      24,400      13,630	-74.8      -77.6
cervix	       13,500       4,641	-76.6      -74.5
rectum	       45,000       7,785	-21.3      -66.9
colon	       111,000      49,204	+21.6      -15.0
larynx	       12,500       3,966	+50.9       -7.4
testicles	     6,300	 355       +113.6      -69.6
bladder	      51,600      10,705	+57.1      -34.8
Hodgkin's disease     7,400       1,639	+17.3      -67.8
childhood cancers     7,800       1,679	 +4.9      -62.4
leukemias	    28,200      19,417	 +8.7       -2.1
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