LUNG CANCER AMONG INDIANS OF THE SOUTHWESTERN UNITED STATES*
By MAURICE L. SIEVERS, M.D.,f and SAMUEL L. COHEN, M.D.,$
Phoenix, Arizona
DESPITE widespread opinion that American Indians seldom develop malignancy, there is little precise information in this regard. The present
report concerns a study of the occurrence of lung cancer among Indians of
the southwestern United States. Data on malignancy discovered in other
parts of the body have been included for comparative purposes.
METHODS AND MATERIALS
One of the authors (S.L.C.) interpreted all chest x-ray films for the
Phoenix Public Health Service Indian Hospital and for most of the area
field units from 1954 to 1960. Information derived from this experience
afforded the primary basis for this study.
The Phoenix P.H.S. Indian Hospital serves as a referral center for nine
field hospitals and seven field clinics located on the numerous Indian reservations in Arizona, Nevada, California, and Utah. Indians residing in the
vicinity of Phoenix or on nearby reservations are also admitted to this general hospital. Some 44 different tribes are represented among the patients
studied, the vast majority of them from the Pima, Apache, Papago, Hopi,
Supai, Hualapai, Yavapai, Mojave, Maricopa, and Navajo tribes. In 1960
the estimated Indian population of reservations served by the Phoenix area
hospitals and field clinics was 76,310.1
All pertinent available hospital records were studied for the period 1954
through 1960 (fiscal years). Material examined included diagnostic files,
medical records, autopsy reports, death certificates, surgical pathologic files,
hospital cancer registry and x-ray files. The death certificate and autopsy
information is based on 234 adult deaths with 153 autopsy examinations
(65.4%).
RESULTS
During the seven-year period 1954 through 1960 (fiscal years), 12,511
patients (8,287 adults) were admitted to the Phoenix P.H.S. Indian Hospital from an estimated population of 76,310 Indians. Although informa* Received for publication November 8, 1960.
From the U. S. Public Health Service Indian Hospital, Phoenix, Ariz.
t Chief of Medical Service, USPHS Indian Hospital, Phoenix, Ariz.
% Consultant in Radiology, USPHS Indian Hospital, and Radiologist, Veterans Administration Hospital, Phoenix, Ariz.
Requests for reprints should be addressed to Maurice L. Sievers, M.D., USPHS Indian
Hospital, 1550 E. Indian School Road, Phoenix, Ariz.
912
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tion on sex distribution is incomplete, it is estimated that there were slightly
fewer adult male than female admissions. Comparative statistics regarding
malignancy of various sites in the study group of Indians are shown in
Table 1.
The information especially pertinent to this investigation is the singular
absence of lung cancer. Gastric malignancy, on the other hand, was discovered in 13 Indians. Among Caucasians of the United States the incidence of cancer of the lung and stomach are similar.2
During the seven-year study period, more than 50,000 chest x-ray films *
of Indians were examined by one of the authors (S.L.C.), without any
primary pulmonary malignancy being detected. Indian inpatients and outTABLE 1
Number of Cases of Malignancy Discovered AmonjI Southwest American Indians
(12,511 Hospital Admissions) by Si te, 1954-1960*
Site
Number of Cases
Stomach
Colon
Gall-bladder and biliary tract
Liver
Pancreas
Breast
Uterus
Ovary
Prostate
Kidney
Penis and testicle
Skin
Bone
Thyroid
Salivary gland
Brain
Unknown site
Lymph nodef
Scalene node (metastasis)
Lung
13
4
8
4
6
5
10
4
6
3
1
4
3
5
1
1
4
5
0
0
* Although the figures presented are for the 12,511 hospitalized individuals, they have
been selected from the total southwestern Indian population of an estimated 76,310.
f Refers to such conditions as Hodgkin's disease or leukemia.
patients at the Phoenix P.H.S. Indian Hospital, nine field hospitals, and
seven field clinics are included among the chest x-ray examinations. Although lung cancer was suggested in the chest x-ray examinations of two
patients, subsequent clinical studies established the pulmonary lesions to be
metastatic.
DISCUSSION
In the death certificate study of Smith et al.,3 it was concluded that the
Navajo, in comparison with the general population, experience a deficit of
cancer in general and, specifically, of cancer of the breast, prostate gland,
•Actually, complete data on enumeration are available for only three years, 1957
through 1959; during this time 15,686 chest films were interpreted for the Phoenix P.H.S.
Indian Hospital and an estimated similar number interpreted for field units.
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914
M. L. SIEVERS AND S. L. COHEN
May 1961
and lung. Similarly, K r a u s 4 reported from his investigation of all the
Indian tribes of Arizona, exclusive of Navajo, that there was significantly
less morbidity and mortality from cancer in Indians than in Caucasians.
This finding existed for each age group, so that the lower life expectancy of
Indians did not explain the discrepancy. No attempt has been made in the
present investigation to compare the occurrence of malignancy of various
types in Indians and in Caucasians. However, the striking absence of lung
cancer in this large segment of Indian population is in extreme contrast to
the situation in the white race, whose death rate from this condition is reported as 16.6 per 100,000 among nonsmokers and 158.8 per 100,000 for
smokers over the age of 55 years. 5
Either hereditary or environmental factors may be related to the apparent
marked deficit of lung cancer among Indians of the southwestern United
States as found in the present study. It is likely that Indians residing on
reservations have little exposure to the environmental factors which are
suggested to have a possible relationship to the development of pulmonary
malignancy. There is apparently very little contamination of the air by
industrial fumes on the isolated reservations. In addition, cigarette smoking is much less frequent among the Indian study group than among Caucasians, and Indians who do use cigarettes seldom do so to the extent common in the white population. Precise data on environmental conditions are
not available, but further investigation of anything which may be related to
the apparent decreased occurrence of lung cancer among Indians of the
southwestern United States seems indicated.
SUMMARY
A striking absence of lung cancer was found among Indians of southwestern United States in a seven-year hospital study. It is not known
whether hereditary or environmental factors are related to this deficit. However, minimal exposure to industrial fumes and infrequent use of cigarettes
among the Indian population may be noteworthy findings. Further investigation is required to determine the conditions of significance in the deficiency
of lung cancer among Indians of this area.
SUMMARIO IN
INTERLINGUA
Le occurrentia de cancere pulmonar inter indianos del sud-west del Statos Unite
esseva evalutate in un septenne studio de radiogrammas thoracic e de varie notationes
hospitalari. Un diagnose de malignitate pulmonar non esseva establite in ulle del
indianos, ben que cancere gastric esseva trovate in 13. Americanos de racia blanc
ha simile incidentias pro cancere pulmonar e pro cancere gastric. Factores de
hereditate o de ambiente debe esser responsabile pro iste marcate deficit de malignitate pulmonar in le indianos del sud-west. II merita possibilemente esser
signalate que le isolate terrenos reservate del indianos suffre un exposition minimal
a vapores industrial e que le indianos studiate es infrequente usatores de cigarrettas.
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BIBLIOGRAPHY
1. Baum, W. S., Schultz, E. A.: Personal communication, 1960.
2. Churchill, E. D., in Cancer, p. 170, American Cancer Society, Inc., 1956.
3. Smith, R. L., Salsbury, D. G., Gilliam, A. G.: Recorded and expected mortality among
the Navajo with special reference to cancer. J. Nat. Cancer Inst. 17: 77, 1956.
4. Kraus, B. S.: Indian health in Arizona. Chapter V I : The disease picture. The University of Arizona Press, Tuscon, 1954.
5. Dorn, H. F.: Note on cigarette smoking and lung cancer. Public Health Rep. 75: 582,
1960.
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