Document 10XO1JNwKYkog6JE4aZ4r135K
FILE NAME Kent KNT
DATE 1954 Mar
DOC KNT135
DOCUMENT DESCRIPTION Journal Article - Etiology of Lung Cancer
Present Status
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Etiology of Lung Cancer Present Status
MORTON L. LEVIN M.D. ALBANY NEW YORK Assistant Commissioner for Medical Services New York State Degurtment Degurtment of Health
\ VAILABLE evidence points to a number of
i
different possible etiologic factors for lung
ranger man These include chemicals radia-
bous dust or fumes encountered by workers in
various occupations and cigaret smoking In-
4
Instries and
occupations with ocupations
evidence of abnor-
mally high lung cancer risks are chromate production production production of illuminating gagsas studied in England ining of uranium ores in Schnee-
F
Terg Germany and Jachymov Czechoslovakia
I
sickel refining in South Wales asbestos manufacturing in England and metal grinding in England Recent evidence points also to increased lung cancer among welders and other workers exposed to metal fumes or dust in the United States Suggestive evidence regarding several other occupations has been reported and atseems seemsseems probable that other as yet unknown occupations with bigh lung cancer risks remain to be
discovered
Evidence for relationship of these occupations to lung cancer consists chiefly of the increased
saortality rate from lung cancer observed among workers in these occupations Exact risks have been estimated for two of these occupations
chromate production in the United States and illuminating gas manufacture in England For few there is also experimental evidence of a carcinogenic agent in the material to which workers are exposed but in no instance has lung cancer been produced in animals by such material In the case of the chromate industry in
shich lung cancer mortality has been showtno
te 14 times that of the United States population
among white workers and 80 times among
Negro workers application or injection into
animals of various materialtso which workers are
eqposed has thus far failed to produce malignant
Studies reported here were aided by a grant from the National Cancer Institute T.S. Public Health Service CS , and from the New York State Division American
Cancer Society
lung tumors Nevertheless there is little or no disagreement as to the existence of a lung cancer etiologie agent in the chromate industry
relationship between lung cancer and tobacco smoking has been suspected for many years Statistical studies of which the first apparently was that of M^...llerin 1939 have uniformly shown a higher percentage of cigaret smokers among lung cancer cases than among control groups In the past few years this relationship has received increasing public notice so that it is today widely debated and discussed in the newspapers in national magazines and no doubt by the public itself Many physicians statisticians and others engaged in cancer research have expressed themselves in the public press as to the significance of the reported studies on this association Considerable difference of opinion and of emphasis has thus been elicited Appraisal of the nature of the evidence regarding tobacco as a possible etiologie factor in lung cancer has thus become of increasing importance because of the widespread public interest and concern over the subject the large financial and tax interests at stake and most important the steadily rising mortality from lung cancer reported each year It is therefore necessary that physicians and public health authorities appraise the situation as
it now exists to determine what conclusions may
be drawn and what action may be required Most studies regarding smoking and lung can-
eer thus far made 13 are listed in a recent arti-
cle have compared the smoking histories of lung cancer patients with those obtained from other persons usually patients with other diseases in the same hospital Almost without exception these studies have found more cigaret smokers among lung cancer patients than among other patients If these observations are valid it would mean that lung cancer occurs more frequently among cigaret smokers than among non-
smokers
March 15 1954
769
MORTON L. LEVIN
i
Several objections can be raised to this type of study and these objections must be carefully weighed to determine what possibilities of error exist in such studies whether these are sufficient
rectly diagnosed groups and were statistical indistinguishable from those of all the othe patients suffering with other discase In the Roswell Park Memorial Institute studies bege
to invalidate the conclusions reached and what in 1938 we consider this source of error to have
bearing the evidence has on the question of smok- been eliminated first because the studies wer 2NN!
ing as cause of lung cancer
undertaken in the belief that no association reaTE
otea The first question which arises with respect to existed and second because of the fact that U
these studies is whether they prove that a real smoking histories were not part of a separate |
|
association exists between smoking and lung terview but were obtained as part of the routits :
|
oe {
cancer In other words do the studies prove history taken on admission before any diagnos
had been made
1
that persons who smoke cigarets develop Jung
ag
: | vy
cancer more frequently than do those who have
A second possible source of error which ha ce
never or rarely smoked for this is the meaning of been pointed out is that one could not be certa
association as used with respect to this type of that the lung cancer cases studied were representa
evidence Association does not mean as has tive of all hung cancer cases or that the contra
been implied by some writers in the press merely that the rise in lung cancer mortality has arcompanied the rise in the use of cigarets The guilt attributed to cigarets is not based on this
jatter type of association The concomitant
rise of lung caucer and cigaret consumption would be expected to follow a true association between the two but by itself cannot be considered as more than suggestive evidence of it
patients were representative of the general popul tion However these two conditions are ne necessary necessary for a valid study of the association two variables First of all the cases and contr need not come from the general population bu
|
from the same population i.e. the contro should be persons of the type most likely to enter the study as cases Second the cases and co | trols need be representative only with respert to
The evidence which is at hand is that cigaret the factors studied in this instance smokin-
smoking is more frequent and heavier among persous who develop lung cancer than among those
who do not
history The theoretic sampling questions raised abov
with respect to the case studies may thus be sum-
The fact that many studies by independent investigators in this country and abroad show the same result is accepted by all or most authorities as proof that some association exists i.c. that cigaret smokers do experience a higher incidence of lung cancer than do nonsmokers It may be of interest however to consider why there should be any doubt at all on this point
Two possible sources of error must be considcred those due to bias in obtaining the history and those due to bins in sampling Where the smoking history is taken as part of a special investigation one must consider whether the interviewer by reason of his own bias or conviction influences the patient in the answers the latter gives In least two studies the element of in-
terviewer bias would seem to have been eliminated
if it existed Doll and Hill considered that they
had demonstrated this error did not exist in their
study since in 335 patients believed to have
marized in the following questions
1. How likely is it that the control and lung . cancer cases in the studies reported were dran |
from two different populations which differe
significantly with respect to smoking and differe :
always so that the control cases came from
smoking population than the lung cater :
?
$
cases ?
2. How likely is it that these sampling biasa: would be more marked for cigaret smokers that|
for pipe and eigar smokers and more marked .. heavy cigaret smokers than for light eigate
smokers
3. How likely is it that lung cancer cases wh ;
smoke are more apt to go to the hospital or that
patients with other diseases who smoke are les :
apt to do so
i
1. How likely is it that these sampling biase
should occur repeatedly in studies made in dig ferent countries and in different sectious of the
bronchial carcinoma at the time of interview but same country
shown later not to have the discuse the smok-
None of these contingencies seems very likeh
ing habits of the wrongly diagnosed group were sharply distinguished from the habits of the cor-
and their occurrence to so marked a degree as
show the differences between smokers and now
=H
senna an
ETIOLOGY OF LUNG CANCER CANCER PRESENT PRESENT STATUS
FABLE Estivated Prevalenge
Prevalenge Rates of Lung Cancen per 100,000 MALES or Seleeren ARET SMOKING HISTORIES
Seleeren Ages and Various Cin-
Number - ++ Lung
Control
Estimated Prevalence
--Quantity --Quantity Smoked
Smoked Dailys-
Heavy Quanti Quanti None
Relative --Prevalencel
All
Quanti
ties
aged 5 to 59 years and Hil
Wynder and tirnham
Sadowsky
Breslow
Gilliam and Cornfield Cornfield
Sadowsky Honglin Rasmussen and Memorial Institute
Abrauis
276
275
94
42
7
**
6
258
210
117
47
27
11
198
208
87
!
12
**
4
213
213
102
40
G
**
v
173
657
111
109
14
**
7
Doll and Hil
Wynder und Sadowsky Gillian
Breslow
199 180
71 169 676
137 138
11
133
63
0 a
Le
70
fl
249
15
73
5
}
1
78
17
23
3
280
50
9
* EstimatEed stimated according to the method of Cornfield Cornfield &
+ All data apappezrping ezring in this table ,
except for
Roswell Park Memorial Institute figures
are taken from
the paper by Bros-
by
} ... L
Quantity smoked daily except for the present study
onverted to their expuivalenta in cigarels as follows
and Hill ounce tobaero
eigarets
eigarets day
is all
forms
of sumaking
expressed
and Wynder
babam
Cill
- eigar
: | pipeful 3 21 cigarets
Cornfield eigar -- cigarets
onnee pipe tobacco = 20 cigarets
study quantity
daily includes includes
only cigaret
smoking
are the following ratios
: heavy -
rate among nonsmokers
rate among heavy smokers among nonsmokers all quantities
or more
defined
following number of eiguraba
eiguraba equivalents
Sadowsky Gilliam and Cornfield 41 or more
per day Doll and III 50 or more Breslow al 10 or more present study
-mokers elicited by the various studies is even lung cancer suffered by eigaret smokers vary
i
|
less likely Their likelihoodis probably least in markedly Table I taken in part from the paper
studies made in hospitals such as those at Ros- by Breslow et al indicates that in the age groups
f
:
i
well Park Memorial Institute in which all pa- fifty to nine and sixty to sixty years
i
tients are admitted without charge and in the inale smokers have lung cancer prevalence rates
British studies of Doll and Hill made in patients
in hospitals coming within the NationaNl ational Health
from four to 15 times as great as among nonsmokers Among heavy smokers according
Insurance scheme Wynder and Cornfield's to varying definitions the relative prevalence is
study made of smoking histories of physicians estimated at seven to 29 times that of non-
aho died of lung cancer also is not subject to the
possible biasofhospitalized cases
smokers Table A presents estimated rates based on
The fact that 13 separate studies have shown tabulation of smoking histories patients ad-
the same resultis strong presumptive evidence mitted to Roswell Park Memorial Institute from
that an association exists between cigaret smok- 1938 to the present These data indicate that
ing and lung cancer i.c. that lung cancer occurs cigaret smokers have at least six times the risk of
more frequently among cigaret smokers than hung cancer incurred by nonsmokers The ex-
among nousn okers Indeed one may predict
that the prospective prospective studies now under way will
ress risk among pipe and cigar smokers is much
,
loss
fully confirm the fact of a substantially increased risk of lung cancer among eigaret smokers However they should provide more precise estimates the magnitude of this risk
In Table HA these data have been recul-
culated after adjusting the place of residence classified into nine population density categories of the noncancer cases to that of the lung cancer
Magnitude of Increased Risk of Lung Cancer Among Cigaret Smokers
cases The indicated relative prevalence among smokers is not significantly altered by this adjust-
ment The relative incidence ratios between
smokers and nonsmokers are based on the as-
increased Estimates of the extent of
risk to
sumption that the differences in smoking history between lung cancer patients and noncancer
Murel 15 1951 771 771
t
MORTON
1
MORTON L. LEVIN 4
TABLE HE
A. Estimated ANNUAL INCIDENCE OF LUNG CANCER PER 100,000 Porelynas Porelynas Amosa Phee CIGAR AND CIGARET SMOKE
45 to 54 55 to 04
no lung cancer
Ratio of Incidence
to Nonsmokers Among
Cagarel Stokera
Pipe
igar Smakri
91.4
in this age group
75 and over
Nonsmokers--
Lung
Non
Cancer
Cauver
1
51
G
122
16
186
BS
163
t
86
Piper Lung Cancer
Smokers-Non-
Cauner
3
==
G
10
95
2
==
37
613
21
Includes pure pipe and eigar * Includes cigaret smokers who also
only smoked pipes and cigars
Cigar Cigar Smokers Non-
Sgareth Laing Cancer
Smoke~-s Nag-
Patient
eet
TABLE III
A. ESTIMATED LUNG CANCH CANCH 100,000 PopULATION AMONG MALE
NONSMOKERS
ANNUAL
INCDENC
CIGARET
INCIDENCE
SMOKERS
PER AND
Aga Group Years
> New York State
Non-
AR
smokers Snickers
Males
Ratio of Incidence
Nonstokers
30 to 39
40 50
to 49
30
to
60 to
70 79
0.8 1.2 14.8 50.3 33.6
3.6 6.0 7.3 5.6 13.0
Rates based on incidence rates rates for lung
York State
exclusive of New York York City for
cancer in New 1949-1951
proximate trite differences in the relative risk
developing lung cancer These data The
IVC indicate that among males aged thirty yea
and over who are light smokers less thanyea
cigarets a day the lung cancer risk is abs
doubled in smokers of five to 19 cigarets a the risk is about six times as great and in the
smoking
20 or more cigarets
t
approximately
times as great as in nonsmokers
In Table V is presented a further analysiosf
smoking history of male lung cancer patients Roswell Park Memorial Institute compared wi
patients admitted with a presumptive diagr
30 to 39 40 to 49 50 to 59 60 to 69 70 to 79
- Nonsmokers
Lung
Non-
Canner
Cancer
38 86 150 205 150
39
636
B. NUMBER OF CASES
-Cigaret -Cigaret Suakers
Lung Cancer
Non-
cancer
170 244 366
Other
Laing
Non-
Cancer
Cancer
cancer
1
z
3
Ez
13
patients reflect similar differences between hung cancer patients and the population from which they come Since there is no reason to believe that the smoking habit per se influences admission to the hospital these ratios probably ap-
i
3
a
4
of lung cancer but whose symptoms upon diagnosis were not due to the presence of by
cancer any lung tumor This is severtees
the difference us to smoking history between :
cancer and other patients since smoking pere
ETIOLOGY OF LUNG CANCER PRESENT STATUS
A, Estimating Axxral Leng CANCER INCIDENCH
TABLE IV
PER 100,000 Asosa Mats ChuAker Smokers AND NONSMOKERS NONSMOKERS BY
Smoken Daily New York StatE
Age Years
480 to 40 to 50 to 60 to 70 to 30 to
: DailyDaily Cigarets Smoked
to 19
20 or more
Nonsmokers
0.S
3.23.2
11.8 50.3 33.6
All Sorokers
" for the bod of caleniating insidener insidenerinsidener rates
* Based on reported lung cancer incidence for Adjusted to population males aged 30 to 70 years
years New York Stute Stute exclusiveexclusive of New
York City 1950 census
:. Pen Crer DiSTRIDiSTBRIBUTUIONSTDiISTROIBUNTIOSNS OF CIGARET CIGARET
Stokers Stokers i^ Dany
Number of Cigarers Svoken
one
meat 10 10 49 50 to 59
MN
Less than 5-
Non-
Long
Cancer
Number of Cigarets Cigarets Cigarets -3 to 19
Non-
Cancer
20 or More
+.
Non-
Long
eumeer
Cancer
46 01
37.34
37.34
29.65
12.10
6.84
- Nonsmokers Nonsmokers
Non-
Lammer
caneer
Cancer
residence of the lung cancer oOTID not shown in this table
COMPARISON OF ESTIMATED ESTIMATED RELATIVE
CreARET CreARET SMOKERY AND
NONSMOKERS
Ve Years
Daily Chaucets Sipoised Sipoised os
5 to
1th
20 or More
All QuantitiesQuantities
50 15 30
6.0
|:
20 to 49
1.9
,
70 to 59
2.2
'
10
69
2
'
to 70
2.1
30 to 797
1.
Relative insidenec ( clusive of New York City 1950 census
olitained alter adjusting adjusting all rates to
population New
TABLE Y
CICARET SMOKERS SMOKERS AMONG PATERNra wien LuxGCANCER WITH OTHER
MALES ROSWELL DISEASES IN
MALES
ROSWELL PARK MEMORIAL
DISEASES THE LUNG
NONTUMORA NONTUMORA
Cases
17 37 46 17
Number
400
*
Includes
18
18
cases
with
history of combination pipe and rigar smoking
not tabulated
inin Table
IIB
* Includes chronic bronchitis bronchiectasis emphysema and other diagnoses
' Comparison here is between cigaret smokers and all others including nonsmokers nonsmokers and pipe and cigar smokers
known to cause in some individuals chronic inflammation of the trachea and bronchial tree
The differences in per cent cigaret smokers between the two groups is statistically significant
WH aC deat
MORTON L. LEVIN
and the indicated relative prevalence from these data of lung cancer among stokers compared to
nonsmokers is still considerable approximately
five times as great
Because the routine method of obtaining smok-
ing histories
is known to understate the preva-
lence of smokers there is reason to believe that
these estimates of relative risk are too low rather
than too high These data confirm those of
previous reports from Roswell Park Memorial
Institutes and by many other investigators that
the lung cancer risk among moderate and heavy cigaret smokers is several times that of non-
smokers
Etiologic Significance
The fact that cigaret sinokers suffer an appreciably increased risk of lung cancer does not of course amount to proof that this increased risk is caused by cigaret smoking It could also be due to the fact that cigaret smoking was in turn associated with some other factor or factors which were carcinogenic or that cigaret smoking enhanced the effect of other carcinogenic factors
Possible factors of this kind which have been
suggested are atmospheric pollution by industrial wastos engine exhaust fumes dust from tarred roads and occupational exposure to carcinogenic dusts or fumes or radiations
The air of some industrial citics is known to
contain benzpyrene and arsenic and mortality rates from lung cancer are higher in cities than in rural areas in this country in England and in Deumark However this would fail to explain the marked excess incidence of lung cancer among males in cities as well as in
rural areas The extensive British studies of Doll
and HEP10 also showed the same excess risk
among smokers when attention was confined to
residents of London Doll,,"has recently reported that the lung cancer incidence antong nonsmokers in England was about the same in London as in rural areas and in females as compared to males These findings suggest that the difference in lung cancer incidence between the sexes and
between rural and urban dwellers may be due to
differences in the prevalence of cigaret smokers in these groups either alone or in combination with
other factors It has not been established
that exposure to air pollution to engine ex-
haust fumes or to dust from tarred roads is
significantly higher among lung cancer cases than among the population from which they come
Lung cancer cases known to arise in occupations which involve increased risk to lung cancer al present account for only a relatively small porcentage of the total cases Admittedly there
may be many more such cases than are recorded and more such occupations than are now known
Two studies correlating smoking history and orcupation in lung cancer cases have been reported In 1,357 male lung cancer cases and 1,357 matched controls Doll found an important exress in the cancer group in only one occupation the production of illuminating gas The cancer
group containined 23 such men the control group
14. Although this difference was not significant it corroborated other evidence gathered also by Doll that gas workers have an excess risk to lung cancer Breslow a study of the smoking and occupational histories of 518 hung cancer eases and 518 controls found 77 lung cancer cases about 15 per cent had an exposure of more than five years to suspect occupations In one of these weiders and sheet metal workers doing welding part of the excess risk was attributable to the high proportion of smokers and a significant portion could not be so explained Unless occupational hazards causing lung cancer are many times more prevalent than any existing evidence indicates they could not possibly explain more than a minor fraction of the observed increase in lung cancer or the excess risk among
smokers
This conclusion has been further tested by a study of the occupational histories and smoking histories of male lung cancer patients and other male cancer patients at Roswell Park Memorial Institute In this study to be reported more } fully in a subsequent publication 137 male lung
cancer cases and 396 control cases were matched
for age and place of residence and adjusted for oe-
cupation The excess of cigaret smokers among
the lung cancer cases remained after the factors of
age residence and occupation were equalized
Table Table
(
VI
Interpretation of the etiologic significance of the smoking cancer association rests on several types of evidence First it conforms
with what is known about other carcinogenic agents Tobacco smoke is known to be an irritant
and to come into contact with the bronchial
Mucos All or most known carcinogens may be classed as irritants although the reverse is not
true and direct contact is one of the most fre
quent modes of effective application of carcino
TABLE VI -ESTIMATED -ESTIMATED
Nonsmokers
Other than
Cikarcts
Fnadjusted for occupation
Lung cancer Control other cancer Lung cancer incidence
among cigaret smok-
ers compared to non-
amokers
Control cases adjusted to
occupational distribu-
tion of lung cancer
cases
Jaung cancer incidence
among cigare smokers
compared
611
non-
smokers adjusted for
mccupation mccupation
8.11 24.21
8.03 28.28
1.00
1.33
23.02
27.81
1.00
1.32
1.32
by Daily Units and Duration
20 or More +
20 per Day Under 40 Years
per Day Under 10 Years
Total Cigarel
10 Years
or More
40
or Mure
Snikers
13.87 10.61
10.95 9.85
27.01 27.01 13.89
35.03 13.13
86.86 86.86 47.48 47.48
6.24 11.87 11.87
5.29 9.38
9.21
12.71
144.18
13.74
8.71 49.17
3,32
8.05
Total Cases
Nitmber
Per
|
Cent
137 396
100.0 100.0 100.0
500.0
gens Second it rests on the failure to demonstrate other snown causes of lung cancer among
smokers as compared with nonsmokers to explain
the excess risk among the former Third and
more indirectly it rests on the conformiance of the rtiniogic hypothesis with the known epidemiologic facts These require that the suspected etiologie age at be one known to have increased markedly in prevalence within the past thirty years as has cigaret smoking and to have affected males more extensively than females
The production of skin cancer in mice by tar obtained from sigaret smoke reported by Wynder Graham anc Croninger adds further support to the belief the cigaret smoke may be a truly etio-
logic factor in lung cancer
All the available evidence thus indicates that
cigaret smoking is one of the contributing causative factors in the production of lung cancer It
does not indicate that it is the sole causative fac-
tor or even that it is operative in the absence of
other factors such as susceptibility and per-
haps other as yet undiscovered etiologic factors
Perhaps the fairest
statement of the case at
present is that there is a strong presumption that
cigaret smoking is an important etiologic factor
cancer It has been estimated previously
that in males cigaret smoking may account for
from 50 to 75 per cent of lung cancer on the as-
sumption that other etiologic factors are equal in
smokers and nonsmokers Recently Doll has
estimated that in England about one in five of
the lung cancer deaths in persons aged twentyfive to seventy in 1950 were attributable to causes other than smoking or about 80 per cent
to smoking
Anticipated Results of Further Research
Total population studies whether retrospertive or prospective should serve to furnish more precise estimates of the magnitude of the excess risk associated with smoking of various Lypes and durations Such studies cannot be expected per se to furnish more information than we now have regarding the etiologic significance of smoking unless accompanied by a concomitant study of all other known or suspected etiologic factors for lung cancer among smokers and nonsmokers Experimental studies now aimed at production of cancer in lung tissue by application of the components of tobacco smoke if successful may add to our confidence in the etiologic nature of the smoking cancer relation
Further study is also indicated of the reasons for the much smaller increased lung cancer risk found among eigar and pipe smokers Possibly some sensitivity test may be devised to distinguish between the majority of smokers who may smoke with relative impunity and the minority who will develop lung cancer The identification of and removal from tobacco of the presumed carcinogenic agent without removal of the tobacco
a
is hopeful possibility
Public Health Implications
Lung cancer is a rapidly increasing cause of
death in this country In New York State it now exceeds tuberculosis in number of deaths among
males
Between 1931-1933 and 1948-1950 ageadjusted lung cancer mortality increased among males in New York State by 385 per cent among
March 15 1954
775
sree
200SPJETOJE
mean
TABLE VII apjuSTER
Smet MORTON L. LEVIN etre che
apjuSTER MOITALITY FROM Larse
TABLE VIU PER CENT PROBABILITY or DEVELOPING
CANCER AND ALL OTHER SITES OF CANCER IN NEW You
LuxG CANCER AND CANCER OF OTHER SITES FROM BIRTH ON
ee
Stare
DEATHS PER 100,000 LivinG
1942 1914 AND 1949 1951
oo
Makes 1931-1933 1918-1950
Females 1931-1933 1948 1950
Per cent change
Lung Cancer
4.7 22.8
2.5 4.2
110.3 112.7
151.2 128.8
Site Male
All sites
LAIT
Female All sites Laing
1912-1944 1912-1944
1949 1951
1949-1931
Adjusted
15.43 0.91
20.17 2.01
18.56 1.87
19.37 0.22
2327 2327 0.34
21.40 0.31
Obtained by holding 1942- 1944 mortality rates from al rauses constant and applying 1949 1951 reported canceriner canceriner
dence rates
Adjusted to 1940 population New York State & Exclusive of New York City
females by 68 per cent Table VU Since cancer is reportable discase in New York State it is possible to calculate the probability of developing rancer of various sites throughout the life span
For lung cancer within the short period between 1942-1944 aud 1949-1951 this probability has more than doubled for males Table VIII At
present rates of incidence 2 per cent of inales may be expected to develop lung cancer If the present rate of increase continues this figure may double again within the next fifteen years
Lung cancer is a public health problem rapidly mounting in importance Public health authorities as well as private medical practitioners must take cognizance of the available facts regarding its occurrence and etiology The following ap-
proaches to the problem are indicated 1. finding Since carly diagnosis
treatment offer the only hope of cure in
and
lung
caneor early finding should be intensified Special attention should be given to the following groups a males aged forty and over b cigarct smokers c persons exposed to known occupational hazards The application of the community chest ray program so extensively developed in this State to the finding of lung cancer has already begun Further refinement
and adaptation of this program to the diagnostic problems of lung cancer are needed
2. Public education The public looks to the
medical profession and to public health authoriLies for information regarding health matters and
for an appraisal of existing evidence regarding
health hazards What shall be our reply to
questions regarding the relation between cigaret smoking and lung cancer The existing evidence
justifies the following statements a Lung cancer occurs more frequently among eigaret smok-
ers and particularly among heavy smokers than among nonsmokers We do not know exactly
how much more frequently it occurs but the evi-
dence we have indicates that the excess risk is ap-
preciable b In the absence of evidence to the contrary the most reasonable assumption is that this increased risk is due to the effect of cigaret smoking either alone or in conjunction with other factors c Persons who are concerned about lung canter cannot be assured that cigaret smoking will not increase their chances of developing the disease d Cigaret smokers particularly those past forty years of age would be well advised to
have chest rays taken at least once a year 3. Research Further research into causes
improved treatment and methods of control of cancer is public health responsibility In New York State this has long been recognized The expanded Roswell Park Memorial Institute at
Buffalo and the Bureau of Cancer Control of the
New York State Departament of Health are devoting considerable attention to investigation of the relation of tobacco to lung larynx lip oral and other types of cancer Investigation is proceeding along the following two main lines @ investigation of the carcinogenic properties of tobacco smake components and b epidemiologie investigation of the characteristics of persons who develop lung cancer and of smokers compared to nonsmokers in an effort to uncover all pertinent
associated factors
Summary
1. The existing evidence regarding the etiology of lung cancer points to the existence of multiple etiologic factors including occupational hazards and cigaret smoking
2. Known occupational hazards do not account for more than a relatively small proportion of lung cancer cases
3. The evidence regarding excess risk of lung cancer attributable to eigaret smoking indicates
that it is several times that among nonsmokers
776
New York State J. Med
HOO SC ESE NOISE ICME AGH
retard nt ae cen
tenses SER nes cae oe
ETIOLOGY OF LUNG CANCER PRESENT STATUS
may account for major part of the incidence lung cancer particularly among males
4. The evidence for excess risk of lung cancer
more than doubled among males in New York
State Two cent of all males may be expected to develop lung cancer at present rates of inci-
sung smokers persists when comparison is made between lung cancer patients and patients with other conditions affecting the lung and bronchi
and when the influence of residence and of oc-
dence Since a majority of adult males are cigaret smokers and most of those over forty have smoked for many years a good deal of the smoking effect probably has already been exerted on
cupation is equalized in lung cancer and control
groups 5. The available evidence is sufficient to
these Hence no appreciable decrease in rates may be expected in the next decade even if everyone forthwith gave up smoking Public
justify public health action in the direction of finding and public health education to the
health efforts hence must concentrate on carly finding and on research
effect that cigaret smoking must be presumed to
play an important role in the production of lung
>
cancer
'
6. Intensive further research in all aspects of
Grateful acknowledgment is made to Mr. Arthur Krans
and Miss Rita Cashinan of the Bureau of
Cancer Control
New York State Department of Health for assistance in the
statistical analysis NOTE Two charts and an additional table will be inebried
the problem s urgently indicated Further in the author's reprints
studies may be expected to provide more pre-
cise data on the magnitude of the excess risk to lung cancer among smokers Additional evidence regarding etiology may be forthcoming from the results of experimental studies but may rest in the final analysis on the study of other possible etiologic factors found in smokers but not in nonsuno At present no such differences are known to explain the excess risk among
References
1 Doll R. Brit
Breslow L. Hoaglin
Meeting of the American Public
.
In press
Ztschr Ztschr I. Krebsforsch 49 57 1989
A. and Croninger A B
Researed 13 855 1958
.
5. Levin M. L. Goldstein H. and Gerhardt P. .:
J.A.M.A. 143 330 1950
Levin
B. Levin
M.
Acta Union Internationale contre le
the former The weight of the evidence therefore indientes that the relationship between
Cancer 9 531
)
7. Wynder
1. and Cornfield .;
Med 248 441 1953
New England J.
"
sigaret smoking and lung cancer is causal and
not merely an association
S. Cornfield .: Nat Cancer Inst 11 1269 1951 9 Doll R. and Hill A. B Brit M. 2 739 1950 10 Thid 1271 1952
7. In less than a decade the chance of de-
11 Doll R. Brit J. Cancer 7 303 1933 12 Moore G. . and Wehr W. H NEW YORK STATE
veloping lung cancer at some time during life has 1. MED 53 2708 1953 !
i
i '
H
5
, i H
i
Medical Society of the State of New York
Hotel Statler March 15 195
May 10 to 14 1954
New York City