Document Details
Comments for the Cancer Risk Criterion Committee
- Click : 0
- Download : 0
- File Size : 19.90 K
- Document Type :
Memo
:
Comments for the Cancer Risk Criterion Committee
1. Do you have any facts/information
that may be useful to the EMC as they evaluate this policy decision?
2. Do you have an opinion/recommendation
to offer as to whether or not the EMC should change the Cancer Risk
factor used in the equation?
BONA FIDES
First, let me establish my
bona fides. I am Professor Emeritus in the Department of Epidemiology
of the School of Public Health of the University of Alabama in Birmingham.
I received my Ph.D. in Pathology/Immunology and M.D. from the University
of Chicago and M.P.H. in Epidemiology from the University of North
Carolina. I have been on the faculty of the Department of Epidemiology
in the School of Public Health at the University of Alabama at Birmingham
for almost 30 years. My foci of teaching and research have been chronic
diseases, including cancer. Since the early 1980's I have been teaching
about risk assessment and risk management. From 1996 to 2000 I was a
member of the Board of Scientific Counselors of the Agency for Toxic
Substances and Disease Registry and Chair of their Community/Tribal
Subcommittee.
BACKGROUND-I have provided
the background below so that you understand the context in which you
are making your decision.
RISK
To understand the concept of
"acceptable risk", it is first necessary to understand the concept
of "risk". The idea that one could actually measure risk is not
a very old concept. It arose out of the need for maritime insurance
in Italy around the 12th century. With the end of feudalism,
entrepreneurs began to own ships. However, in order to avoid the new
risk of bankruptcy if a ship went down, insurance was invented. To determine
the premium, it was necessary for the insurance company to measure the
probability of a ship going down. This was the "riscio", a
word, the etymology of which comes from Greek and Latin and relates
to a ship being destroyed by rocks. When maritime insurance came to
England through Lloyd's of London, the paper describing the ship and
its passage which Lloyd's was showing to the potential underwriters,
was the "risqué". Given the Anglo-Saxon fondness for four-letter
words, it was later shortened to "risk." Later, insurance was extended
to "life-insurance" [really "death-insurance"].
The first measurement of "risk"
in a public health context was the comparison of the risk of developing
smallpox after being given a smallpox vaccination compared to the risk
in those unvaccinated. Dr. John Snow gave the science of epidemiology
its start when he calculated the risk of developing cholera among those
who got their water from a water company which drew its water downstream
of London on the Thames versus the risk to those whose water came from
upstream. In each of these examples, the "risk" was the ratio of
those who became cases divided by all those who were potential cases.
The modern measurement of risk
in the environmental circumstances began in the 1960's with the desire
to compare the risks of nuclear energy with other sources of energy.
It grew as the result of the National Environmental Policy Act of 1969
and the development of the Occupational Safety and Health Administration
in the 1970's. Risk assessment (also called risk analysis) became
central when the Supreme Court decided that the US
EPA proposed regulation on
Benzene could not be supported unless "Significantly lower risks could
be demonstrated." In the 1980's it was recognized that there was
a need for data and standards for Risk Assessment so in 1982 the Risk
Analysis Research and Demonstration Act established the Office of Science
and Technology Policy Risk Analysis to "define criteria and standards
to guide the development and use of risk analysis" and "improve
the methodologies." Among the Federal agencies which use risk assessment
are EPA, FDA, OSHA, Consumer Product Safety Commission, and ATSDR. For
the estimate of risk related to carcinogens, the EPA uses the equation,
Risk = dose X incidence/dose.
ACCEPTABLE RISK
One of the earliest discussions
of what is an "acceptable risk" was by William Farr in his 1868
analysis of the mortality of riders on the English railway. He estimated
that "a season ticket-holder who is on an average railway
only an hour a day for 300 days adds less than one -10,000th
to his risk; it is, therefore, below the degree of commonly appreciated
danger. For double the time the risk may be doubled; but even this is
only an addition of 2 to the ordinary risk of 150 per 10,000 from all
other causes incurred by a life at the age of fifty. Insurance
offices constantly neglect such slight additional risks in dealing with
men living in different circumstances, in different professions. As
the assayer of gold cannot test its fineness from alloy with any certainty
beyond the 2 or 3 ten thousandth part, so it is in scientific assays
of the value of human life." [Today, the assayers of gold can test
its fineness to many more orders of magnitude than in Farr's day,
and we are discussing the acceptability of risks 1 to 2 orders of magnitude
lower.]
What societies determine to
be an acceptable risk has been the subject of considerable discussion.
"The general consensus is that 'acceptibility' of a risk is a
judgement decision properly made by those exposed to the hazard or their
designated health officials. It is not a scientifically derived value.."
None-the-less, Chauncy Starr proposed three "Laws of Acceptable Risk".
The first law is that the public is willing to accept voluntary risk
roughly 1000 times greater than involuntarily imposed risks. This is
consistent with the apparent dissonance displayed by when a smoker is
concerned about the concentration of possible carcinogenic chemicals
in the water bodies they use for drinking, fishing and swimming. It
is also consistent with the considerably high risk which is acceptable
in the occupational setting than in the environmental setting. The second
law is that the statistical risk from disease appears to be a psychological
yardstick for establishing the level of acceptability of other risks.
This is a possible explanation for the lower level of acceptable risk
today compared to Farr's day since the risk of disease is considerably
lower today. The third law is that the acceptability of risk appears
to be crudely proportional to the third power of the benefits (real
or imagined). Research by Ottway and Cohen found that for voluntary
risks it was to the 1.8 power; for involuntary risks, to the 6th
power. Although it is not one of his laws, Starr wrote, "Public acceptance
of any risk is more dependent on public confidence in risk management
than on the quantitative estimates of risk consequences, probabilities
and magnitude." [Perhaps if there were more public confidence in ADEM,
there would not be the public request to lower the level of acceptable
risk of carcinogenic chemicals in water.]
There have been a number of
legal approaches to establishing acceptable risk criteria. With respect
to carcinogens in food, The Delaney
clause, named after Congressman James Delaney of New York and tacked
onto the Federal Food, Drugs, and Cosmetic Act in 1958, said, "the
Secretary [of the Food and Drug Administration] shall not approve for
use in food any chemical additive found to induce cancer in man, or,
after tests, found to induce cancer in animals." As the ability
to detect lower and lower concentrations of chemicals, there has been
a effort to move away from the zero acceptable risk criterion as required
by the Delaney clause toward what has been called, "DeMinimus Risk."
This comes from the legal theory, "DeMinimis non curat lex" (the
law does not concern itself with trifles). The Supreme Court ruled that
the EPA had power "in most statutory schemes to overlook circumstances
that in contest may fairly be considered DeMinimus." The question
is what is a DeMinimis risk. "The first use of 'acceptable
risk' in any environmental guidance appears to have been a part of
the Superfund Public Health Evaluation Manual, issued in 1986
and now superseded by the 1900 National Contingency Plan. The original
Superfund guidelines stated: '. remedies considered should
reduce ambient chemical concentrations to levels associated with a carcinogenic
risk range of 10-4 to 10-7.' This range was
modified to 10-4 to 10-6 in the final NCP."
Subsequently for almost all regulatory decisions concerning carcinogens,
EPA has used 10-6 as the acceptable risk criterion.
In summary, the decision about what is
the acceptable risk criterion is not a scientific decision, but a decision
about what kind of state you, as the representatives of the people of
Alabama, want the citizens to live in. I urge you to lower the acceptable
risk criterion to 10-6, showing a commitment to protecting
human health and a conviction that Alabama can be economically competitive
with the surrounding states even as it adopts similar levels of acceptable
risk of cancer to theirs.
7. Please provide documentation
of cancer types associated with each of the 58 carcinogens potentially
impacted by the change and incidence rates of these cancers in the State
of Alabama; particularly in, but not limited to, the very young and
very old.
a. Please provide documentation
as to whether these incidence rates have generally
risen or generally fallen over
the course of the last 10 years (trends) and, if
possible, reasons for the rise
or fall.
b. Please provide supporting
documentation from current literature (preferably
within, but not limited to,
the last 5 years) for a link or potential link between any
case of these types of cancers
in Alabama and the discharge of these 58
carcinogens. "Cancer cluster"
reports and documentation are acceptable.
c. Where geographically in
the State are these cancer types most often located?
d. In which ethnic subpopulation
(White, Hispanic, African-American, Asian, etc.)
are these cancer types most
often seen?
In order to address the first
part of Question 7 as to the "documentation of cancer types associated
with each of the 58 carcinogens potentially impacted by the change,
I have attached an Excel file of the ADEM regulated chemicals in water,
the weight-of-evidence that it is a carcinogen and for those for which
there is evidence of possible carcinogenicity the sites with which they
might be associated. The information about the weight-of-evidence with
respect to carcinogenicity comes from the IRIS database of the EPA.
In this database, A is a known Human
carcinogen; B1, Probable human carcinogen - based on limited evidence
of carcinogenicity in humans and sufficient evidence of carcinogenicity
in animals; B2, Probable human carcinogen - based on sufficient evidence
of carcinogenicity in animals; C, Possible human carcinogen; D, Not
classifiable as to human carcinogenicity, and E, Evidence of non-carcinogenicity
for humans. Where there
is only evidence of carcinogenicity in animals, I have identified those
animal cancer sites which have been reported as increased when exposed
to the particular chemical.
[It should be noted that for
some of these chemicals, even if there is no evidence that the chemical
is a carcinogen, there may be evidence that the chemical has other health
effects and the non-carcinogenic acceptable risk also needs to be determined.
]
The latest available top ten
cancer incidence rates in Alabama can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=n
15. Please provide the cancer
incidence rate trends in cancers associated with the 58 carcinogens
affected in Region 4 states currently using a cancer risk factor of
10-6.
The latest top ten cancer incidence
rates by state can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=n
The rankings of the states with respect
to incidence by cancer site can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=4fb&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=4fb&Year=2003&Display=n
It should be noted that this is not available
for liver cancer which is one of the likely cancers to be caused by
these chemicals. This is because the incidence rate for liver cancer
is 8.2 per 100, 000 per year in the US which does not put it in the
top 10 cancers.
The trends in state rates (usually mortality
rather than incidence) can be found at the following website:
http://statecancerprofiles.cancer.gov/
20. What are the prevalent
types of cancer that are present in Alabama, what are the statistical
levels, and what is the current state of the science on understanding
the most probable factors that cause these different types of cancer?
There are no reliable estimates
of the most prevalent types of cancer in Alabama, however, the top 10
cancers by age-adjusted incidence (all per 100,000 persons) in Alabama
in 2003 were, in order of incidence (all races, both genders combined)
with the most probable causal factors identified:
Prostate-140.8
Primary cause unknown
Lung and Bronchus-104.9
Smoking, radon,
Colon & Rectum-60.9
Primary cause unknown
Urinary Bladder-30.3
Smoking, Arylamines, PAHs, bladder infections
Oral Cavity & Pharynx-18.6
Smoking, Smokeless tobacco
Non-Hodgkins Lymphoma-18.5
Weakened immune system, certain infections,
herbicides?, hair dyes?
Kidney & Renal Pelvis-18.2
Primary cause unknown, smoking, cadmium, asbestos
Melanomas of the Skin-16.7
Sun exposure, weakened immune system
Pancreas-12.0
Primary cause unknown, smoking, alcohol, beta-
naphthalene and benzidine
Leukemias-10.9
Cause varies by leukemia type-Benzene exposure is
causal for CLL.
21. Is there a clear cause
and effect for cancer that can be attributed to environmental factors
other than the water quality standards in our regulations?
There are environmental factors,
other than water quality standards in our regulations that have been
demonstrated causal of cancer. They include asbestos, cadmium, radiation,
beryllium and hexavalent chromium
22. If there are other environmental
factors that attribute to cancer in the citizens of Alabama, how do
we determine the relative improvement in risk to the population by changing
only one factor such as water quality standards?
You can't.
27. Is there any correlation
between the magnitude of the two risk factors and the incidence or mortality
rates for cancer?
It is not clear to what two
risk factors this question refers.
28. Is there any evidence of
cancer incidence attributed to the consumption of fish or raw water
from Alabama streams?
None that I am aware of, however,
I am also not aware of any effort to try to determine if there is such
an association, and such a study would be extremely difficult to carry
out to demonstrate convincingly an association.
33. Is there any scientific
evidence to link a lowering of the cancer risk level to 10-6
to a corresponding lowering of cancer incidence?
No. It would be impossible to detect
the effect on incidence trends in cancer of a policy which would reduce
the acceptable risk criterion from 10-5 to 10-6.
The difference between 10-5 and 10-6 is 9 X 10-6.
This is the difference in lifetime risk so to estimate its effect on
the annual rate we need to divide this by 70 years. This is about 13
X 10-8 excess cases per year.
As an example of how difficult it would
be to detect these excess cases in Alabama or even the US, let us look
at the situation with liver cancer. Liver cancer is one of those cancer
types which would be likely to be caused by exposure to carcinogens
in the water. If we estimate that there are 4 X 106
people in Alabama [3 X 108 in the US] and the incidence rate
of liver cancer is 8.2 X 10-5, then the expected number of
liver cancers in Alabama each year is around 328 [24600 in the US].
If the criterion were lowered to 10-6 then we would expect
at most one of those cases per year might be eliminated in Alabama [5
in the entire US]. Such a difference would be impossible to detect through
current epidemiologic methods. It would be even more impossible to detect
such an effect for more common cancers such as lung or colon cancer.
Although the effect would be difficult
to detect epidemiologically, lowering the acceptable risk criterion
has the potential to spare many Alabamians an occurrence to cancer.
Since the difference is 9 X 10-6 and the population of Alabama
is approximately 4 X 106, assuming all are exposed, then
36 persons would be spared an occurrence of cancer for each chemical
and if we assume that each of the 50+ chemicals is an independent cause
of cancer over 1800 Alabamians will be spared an occurrence of cancer
from reduced exposure to all the chemicals.
Comments for the Cancer Risk Criterion Committee
1. Do you have any facts/information
that may be useful to the EMC as they evaluate this policy decision?
2. Do you have an opinion/recommendation
to offer as to whether or not the EMC should change the Cancer Risk
factor used in the equation?
BONA FIDES
First, let me establish my
bona fides. I am Professor Emeritus in the Department of Epidemiology
of the School of Public Health of the University of Alabama in Birmingham.
I received my Ph.D. in Pathology/Immunology and M.D. from the University
of Chicago and M.P.H. in Epidemiology from the University of North
Carolina. I have been on the faculty of the Department of Epidemiology
in the School of Public Health at the University of Alabama at Birmingham
for almost 30 years. My foci of teaching and research have been chronic
diseases, including cancer. Since the early 1980's I have been teaching
about risk assessment and risk management. From 1996 to 2000 I was a
member of the Board of Scientific Counselors of the Agency for Toxic
Substances and Disease Registry and Chair of their Community/Tribal
Subcommittee.
BACKGROUND-I have provided
the background below so that you understand the context in which you
are making your decision.
RISK
To understand the concept of
"acceptable risk", it is first necessary to understand the concept
of "risk". The idea that one could actually measure risk is not
a very old concept. It arose out of the need for maritime insurance
in Italy around the 12th century. With the end of feudalism,
entrepreneurs began to own ships. However, in order to avoid the new
risk of bankruptcy if a ship went down, insurance was invented. To determine
the premium, it was necessary for the insurance company to measure the
probability of a ship going down. This was the "riscio", a
word, the etymology of which comes from Greek and Latin and relates
to a ship being destroyed by rocks. When maritime insurance came to
England through Lloyd's of London, the paper describing the ship and
its passage which Lloyd's was showing to the potential underwriters,
was the "risqué". Given the Anglo-Saxon fondness for four-letter
words, it was later shortened to "risk." Later, insurance was extended
to "life-insurance" [really "death-insurance"].
The first measurement of "risk"
in a public health context was the comparison of the risk of developing
smallpox after being given a smallpox vaccination compared to the risk
in those unvaccinated. Dr. John Snow gave the science of epidemiology
its start when he calculated the risk of developing cholera among those
who got their water from a water company which drew its water downstream
of London on the Thames versus the risk to those whose water came from
upstream. In each of these examples, the "risk" was the ratio of
those who became cases divided by all those who were potential cases.
The modern measurement of risk
in the environmental circumstances began in the 1960's with the desire
to compare the risks of nuclear energy with other sources of energy.
It grew as the result of the National Environmental Policy Act of 1969
and the development of the Occupational Safety and Health Administration
in the 1970's. Risk assessment (also called risk analysis) became
central when the Supreme Court decided that the US
EPA proposed regulation on
Benzene could not be supported unless "Significantly lower risks could
be demonstrated." In the 1980's it was recognized that there was
a need for data and standards for Risk Assessment so in 1982 the Risk
Analysis Research and Demonstration Act established the Office of Science
and Technology Policy Risk Analysis to "define criteria and standards
to guide the development and use of risk analysis" and "improve
the methodologies." Among the Federal agencies which use risk assessment
are EPA, FDA, OSHA, Consumer Product Safety Commission, and ATSDR. For
the estimate of risk related to carcinogens, the EPA uses the equation,
Risk = dose X incidence/dose.
ACCEPTABLE RISK
One of the earliest discussions
of what is an "acceptable risk" was by William Farr in his 1868
analysis of the mortality of riders on the English railway. He estimated
that "a season ticket-holder who is on an average railway
only an hour a day for 300 days adds less than one -10,000th
to his risk; it is, therefore, below the degree of commonly appreciated
danger. For double the time the risk may be doubled; but even this is
only an addition of 2 to the ordinary risk of 150 per 10,000 from all
other causes incurred by a life at the age of fifty. Insurance
offices constantly neglect such slight additional risks in dealing with
men living in different circumstances, in different professions. As
the assayer of gold cannot test its fineness from alloy with any certainty
beyond the 2 or 3 ten thousandth part, so it is in scientific assays
of the value of human life." [Today, the assayers of gold can test
its fineness to many more orders of magnitude than in Farr's day,
and we are discussing the acceptability of risks 1 to 2 orders of magnitude
lower.]
What societies determine to
be an acceptable risk has been the subject of considerable discussion.
"The general consensus is that 'acceptibility' of a risk is a
judgement decision properly made by those exposed to the hazard or their
designated health officials. It is not a scientifically derived value.."
None-the-less, Chauncy Starr proposed three "Laws of Acceptable Risk".
The first law is that the public is willing to accept voluntary risk
roughly 1000 times greater than involuntarily imposed risks. This is
consistent with the apparent dissonance displayed by when a smoker is
concerned about the concentration of possible carcinogenic chemicals
in the water bodies they use for drinking, fishing and swimming. It
is also consistent with the considerably high risk which is acceptable
in the occupational setting than in the environmental setting. The second
law is that the statistical risk from disease appears to be a psychological
yardstick for establishing the level of acceptability of other risks.
This is a possible explanation for the lower level of acceptable risk
today compared to Farr's day since the risk of disease is considerably
lower today. The third law is that the acceptability of risk appears
to be crudely proportional to the third power of the benefits (real
or imagined). Research by Ottway and Cohen found that for voluntary
risks it was to the 1.8 power; for involuntary risks, to the 6th
power. Although it is not one of his laws, Starr wrote, "Public acceptance
of any risk is more dependent on public confidence in risk management
than on the quantitative estimates of risk consequences, probabilities
and magnitude." [Perhaps if there were more public confidence in ADEM,
there would not be the public request to lower the level of acceptable
risk of carcinogenic chemicals in water.]
There have been a number of
legal approaches to establishing acceptable risk criteria. With respect
to carcinogens in food, The Delaney
clause, named after Congressman James Delaney of New York and tacked
onto the Federal Food, Drugs, and Cosmetic Act in 1958, said, "the
Secretary [of the Food and Drug Administration] shall not approve for
use in food any chemical additive found to induce cancer in man, or,
after tests, found to induce cancer in animals." As the ability
to detect lower and lower concentrations of chemicals, there has been
a effort to move away from the zero acceptable risk criterion as required
by the Delaney clause toward what has been called, "DeMinimus Risk."
This comes from the legal theory, "DeMinimis non curat lex" (the
law does not concern itself with trifles). The Supreme Court ruled that
the EPA had power "in most statutory schemes to overlook circumstances
that in contest may fairly be considered DeMinimus." The question
is what is a DeMinimis risk. "The first use of 'acceptable
risk' in any environmental guidance appears to have been a part of
the Superfund Public Health Evaluation Manual, issued in 1986
and now superseded by the 1900 National Contingency Plan. The original
Superfund guidelines stated: '. remedies considered should
reduce ambient chemical concentrations to levels associated with a carcinogenic
risk range of 10-4 to 10-7.' This range was
modified to 10-4 to 10-6 in the final NCP."
Subsequently for almost all regulatory decisions concerning carcinogens,
EPA has used 10-6 as the acceptable risk criterion.
In summary, the decision about what is
the acceptable risk criterion is not a scientific decision, but a decision
about what kind of state you, as the representatives of the people of
Alabama, want the citizens to live in. I urge you to lower the acceptable
risk criterion to 10-6, showing a commitment to protecting
human health and a conviction that Alabama can be economically competitive
with the surrounding states even as it adopts similar levels of acceptable
risk of cancer to theirs.
7. Please provide documentation
of cancer types associated with each of the 58 carcinogens potentially
impacted by the change and incidence rates of these cancers in the State
of Alabama; particularly in, but not limited to, the very young and
very old.
a. Please provide documentation
as to whether these incidence rates have generally
risen or generally fallen over
the course of the last 10 years (trends) and, if
possible, reasons for the rise
or fall.
b. Please provide supporting
documentation from current literature (preferably
within, but not limited to,
the last 5 years) for a link or potential link between any
case of these types of cancers
in Alabama and the discharge of these 58
carcinogens. "Cancer cluster"
reports and documentation are acceptable.
c. Where geographically in
the State are these cancer types most often located?
d. In which ethnic subpopulation
(White, Hispanic, African-American, Asian, etc.)
are these cancer types most
often seen?
In order to address the first
part of Question 7 as to the "documentation of cancer types associated
with each of the 58 carcinogens potentially impacted by the change,
I have attached an Excel file of the ADEM regulated chemicals in water,
the weight-of-evidence that it is a carcinogen and for those for which
there is evidence of possible carcinogenicity the sites with which they
might be associated. The information about the weight-of-evidence with
respect to carcinogenicity comes from the IRIS database of the EPA.
In this database, A is a known Human
carcinogen; B1, Probable human carcinogen - based on limited evidence
of carcinogenicity in humans and sufficient evidence of carcinogenicity
in animals; B2, Probable human carcinogen - based on sufficient evidence
of carcinogenicity in animals; C, Possible human carcinogen; D, Not
classifiable as to human carcinogenicity, and E, Evidence of non-carcinogenicity
for humans. Where there
is only evidence of carcinogenicity in animals, I have identified those
animal cancer sites which have been reported as increased when exposed
to the particular chemical.
[It should be noted that for
some of these chemicals, even if there is no evidence that the chemical
is a carcinogen, there may be evidence that the chemical has other health
effects and the non-carcinogenic acceptable risk also needs to be determined.
]
The latest available top ten
cancer incidence rates in Alabama can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=n
15. Please provide the cancer
incidence rate trends in cancers associated with the 58 carcinogens
affected in Region 4 states currently using a cancer risk factor of
10-6.
The latest top ten cancer incidence
rates by state can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=3f&Year=2003&Display=n
The rankings of the states with respect
to incidence by cancer site can be found at the following website:
<a href=http://apps.nccd.cdc.gov/uscs/Table.aspx?Group=4fb&Year=2003&Display=nhttp://apps.nccd.cdc.gov/uscs/Table.aspx?Group=4fb&Year=2003&Display=n
It should be noted that this is not available
for liver cancer which is one of the likely cancers to be caused by
these chemicals. This is because the incidence rate for liver cancer
is 8.2 per 100, 000 per year in the US which does not put it in the
top 10 cancers.
The trends in state rates (usually mortality
rather than incidence) can be found at the following website:
http://statecancerprofiles.cancer.gov/
20. What are the prevalent
types of cancer that are present in Alabama, what are the statistical
levels, and what is the current state of the science on understanding
the most probable factors that cause these different types of cancer?
There are no reliable estimates
of the most prevalent types of cancer in Alabama, however, the top 10
cancers by age-adjusted incidence (all per 100,000 persons) in Alabama
in 2003 were, in order of incidence (all races, both genders combined)
with the most probable causal factors identified:
Prostate-140.8
Primary cause unknown
Lung and Bronchus-104.9
Smoking, radon,
Colon & Rectum-60.9
Primary cause unknown
Urinary Bladder-30.3
Smoking, Arylamines, PAHs, bladder infections
Oral Cavity & Pharynx-18.6
Smoking, Smokeless tobacco
Non-Hodgkins Lymphoma-18.5
Weakened immune system, certain infections,
herbicides?, hair dyes?
Kidney & Renal Pelvis-18.2
Primary cause unknown, smoking, cadmium, asbestos
Melanomas of the Skin-16.7
Sun exposure, weakened immune system
Pancreas-12.0
Primary cause unknown, smoking, alcohol, beta-
naphthalene and benzidine
Leukemias-10.9
Cause varies by leukemia type-Benzene exposure is
causal for CLL.
21. Is there a clear cause
and effect for cancer that can be attributed to environmental factors
other than the water quality standards in our regulations?
There are environmental factors,
other than water quality standards in our regulations that have been
demonstrated causal of cancer. They include asbestos, cadmium, radiation,
beryllium and hexavalent chromium
22. If there are other environmental
factors that attribute to cancer in the citizens of Alabama, how do
we determine the relative improvement in risk to the population by changing
only one factor such as water quality standards?
You can't.
27. Is there any correlation
between the magnitude of the two risk factors and the incidence or mortality
rates for cancer?
It is not clear to what two
risk factors this question refers.
28. Is there any evidence of
cancer incidence attributed to the consumption of fish or raw water
from Alabama streams?
None that I am aware of, however,
I am also not aware of any effort to try to determine if there is such
an association, and such a study would be extremely difficult to carry
out to demonstrate convincingly an association.
33. Is there any scientific
evidence to link a lowering of the cancer risk level to 10-6
to a corresponding lowering of cancer incidence?
No. It would be impossible to detect
the effect on incidence trends in cancer of a policy which would reduce
the acceptable risk criterion from 10-5 to 10-6.
The difference between 10-5 and 10-6 is 9 X 10-6.
This is the difference in lifetime risk so to estimate its effect on
the annual rate we need to divide this by 70 years. This is about 13
X 10-8 excess cases per year.
As an example of how difficult it would
be to detect these excess cases in Alabama or even the US, let us look
at the situation with liver cancer. Liver cancer is one of those cancer
types which would be likely to be caused by exposure to carcinogens
in the water. If we estimate that there are 4 X 106
people in Alabama [3 X 108 in the US] and the incidence rate
of liver cancer is 8.2 X 10-5, then the expected number of
liver cancers in Alabama each year is around 328 [24600 in the US].
If the criterion were lowered to 10-6 then we would expect
at most one of those cases per year might be eliminated in Alabama [5
in the entire US]. Such a difference would be impossible to detect through
current epidemiologic methods. It would be even more impossible to detect
such an effect for more common cancers such as lung or colon cancer.
Although the effect would be difficult
to detect epidemiologically, lowering the acceptable risk criterion
has the potential to spare many Alabamians an occurrence to cancer.
Since the difference is 9 X 10-6 and the population of Alabama
is approximately 4 X 106, assuming all are exposed, then
36 persons would be spared an occurrence of cancer for each chemical
and if we assume that each of the 50+ chemicals is an independent cause
of cancer over 1800 Alabamians will be spared an occurrence of cancer
from reduced exposure to all the chemicals.