U thought that only cancer of the uterine

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1 ALARMING INCREASE OF THE CANCER MORTALITY IN THE U.S. BLACK POPULATION ( ) ULRICH K. HENSCHKE, MD, PHD," LASALLE CLAUDIA H. MASON, PHD,~ ANDREAS W. REINHOLD, BSc,( ROY L. SCHNEIDER, MD," AND JACK E. WHITE, MD"" D. LEFFALL, JR., MD,+ The U.S. cancer mortality per 100,000 for both sexes rose, from 1950 to 1967, for blacks from 147 to 177, an increase of 2076, while it remained unchanged for whites at 150. The female cancer mortality rate declined for blacks from 146 to 142, a decrease of only 396, while it declined for whites from 139 to 126, a decrease of 9%. The male cancer mortality rate rose for blacks from 147 to 220, an increase of 50%, while it increased for whites from 158 to 181, an increase of only 16%. In 1950, the cancer mortality rate for both sexes was 2% lower for blacks than for whites, but, by 1967, it had become 18% higher. Of the 58 most frequent U.S. sex-specified cancer types, 29 increased slower in whites, 9 decreased faster in whites, 14 showed no significant differences, and only 4 (malignant melanoma and reticulum cell sarcoma in both sexes) increased faster in whites. Environmental factors are the most likely causes for this alarming rise of cancer in U.S. blacks. NTIL A FEW YEARS AGO IT WAS COMMONLY U thought that only cancer of the uterine cervix was significantly more prevalent in blacks. Recently, however, several other cancers were found to be more frequent in U.S. blacks than in U.S. whites. Seidman,6 in a study by the American Cancer Society, reported significantly greater mortality rates for Supported by the Metropolitan Washington Regional Medical Program Grant RPG-1533 (Cancer Radiothcrapy [Init) antl by the National Canccr Institutc Grant ME-RPG 1619 (Howard University Cancer Centcr Exploration Study). * Professor and Chairman, Department of Ratliothcrapy, Howard [Jniversity College of Medicine. t Professor and Chairman, Department of Surgery, Howard University College of Medicinc. t Assistant Professor of Biostntistics, Department of Community Medicinc, Georgetown LJniversity. I Sophomore stridcnt, Howard IJniversity College of Dentistry. 'I Instructor in Radiotherapy antl Surgery, Howard Llnivcrsity College of Metlicinc. ** Professor of Surge]-y antl Director of thc Cancer Rrscarcli Center, Howard University College of Mcdicine. Address for reprints: U. Henschkc, MD, Departmcnt of Radiotherapy, Collegc of Medicine, Howard IJniversity, Washington, D.C For advice and discussions, we wish to thank Dr. Cuylcr Hammond and Mr. Herbert Seidman from the Dcpartment of Epidemiology and Statistics of the American Cancer Society, as well as Dr. Marvin,4. Schneiderman, Dr. Robert W. Miller. Dr. Joseph P. Fraumeni. and Mr. Thomas Mason from the National Cancer Institute. Received for publication September 19, l97?. 763 New York City blacks, for the years 1949 to 1951, for cancer of the male esophagus, stomach, male liver combined with biliary passages, pancreas, male larynx, prostate, cervix, and female bladder. Higher mortality rates for U.S. blacks than for U.S. whites were also reported for cancer of the pancreas by Krain4 and for cancer of the prostate by Wynder et al.1" The most detailed data on racial differences of cancer mortality in the United States are contained in Report 33 of the National Cancer Institute.' This report gives the age-specific and age-adjusted cancer mortality rates for the most important cancer types for the years 1950 tliroiigh 1967, for all states of the U.S.A., and is an impressive example of the use and the potential of large computers in medical statistics. Its shortcomings from our point of view are that it lumps all minority groups together under "non-white," and that it assigns to the state of Maryland the data of the District of Columbia, although the District of Columbia has a larger population than 11 states. Figures from the District of Columbia would be of special interest, hecause it has a larger percentage of blacks (71y0) than any state. As we have pointed out in a previous publication,3 a comparison of the black antl

2 764 CANCER April 1973 Vol. 31 white cancer mortality in the United States can be made from the figures published yearly in the Official Statistics of the U.S.A. We found that from 1949 until 1967, the average yearly increase in the number of deaths from all cancers was 2.0 times higher for the total black than for the total white U.S. population (5.001, vs. 2.5Yn7,), 1.7 times higher for black females than for white females (3.2y0 vs. 1.9yo), and 2.3 times higher for black males than for white males (7.1% vs. 3.1%). Of the 24 most frequent U.S. cancers studied, 18 showed a more rapid increase of the cancer deaths in blacks than in whites. Our previous study on black-white cancer trends was originally undertaken to determine the present and future need of the U.S. black population for cancer care. We were primarily interested, therefore, in the total number of black cancer patients. In this study, we will investigate the trends of the cancer mortality rates, usually given by the number of people per 100,000 who die from cancer in the report year. Cancer mortality rates are more revealing than the number of cancer deaths for studies on the cause and prevention of cancer. TREND OF MORTALITY RATES Table 1 shows a comparison of the trends of the mortality rates for all cancers for the U.S. black and white population. We computed these figures from the data in the Official Statistics of the United States for the years 1950 and They are age-adjusted to the total population of the United States for The year 1967 was chosen because it is the latest year for which this report was available, while 1950 was elected to make our data more readily comparable with the data in Report 33 of the National Cancer Institute. Our figures in Table 1 show that from 1950 TABLE 1. Trend of Black and White Mortality Rates for All Cancers, Age-Adjusted to the Total 1960 US. Population Change Sex Race to1967 Rothsexes Blacks % Whites % Females Blacks % Whites % Males Blacks SO90 Whites % to 1967, the age-adjusted cancer mortality rate for both sexes increased by 20yo in blacks while it remained unchanged in whites. The cancer mortality rate for females decreased in both races, but the decrease of 3y0 for black females was much less than in white females, for whom the cancer mortality rate declined by 9yo. For males, the cancer mortality rate increased by 50% in blacks, while it increased in whites by only 16%. The calculation for each particular year shows that the cancer mortality for both sexes was 2% lower in 1950, but 18% higher in 1967 for blacks than for whites. For black females, it was 5% higher in 1950 and 13% higher in 1967 than for white females. For black males, it was 7y0 lower in 1950 but 21% higher in 1967 than for white males. A comparison of our figures with the mortality rates given by Burbankl in Report 33 of the National Cancer Institute shows that the figures for whites are the same. Burbank does not give figures for blacks, but only for a group called non-whites. For females, Burbank s non-white rate is 1% higher than our rate for blacks. For males, Burbank s mortality rate for non-whites is 1%-2y0 lower than FOR ALL CANCERS our mortality rates for blacks. The clifferences in mortality rates between blacks and nonwhites are thus small, which is due to the fact that the great majority of the non-whites are blacks (91.3oj, in 1967). TREND OF MORTALITY RATES FOR MOST FREQUENT U.S. CANCERS Table 2 shows a comparison of the trends of the cancer mortality for the 58 sex-specified cancer types, which caused more than 500 deaths in the US. in Together these 58 cancer types accounted for 94y0 of all U.S. cancer deaths. The basic data for this table were taken from Repor: 33 of the National Cancer Institute. As pointed out above, the figures in this report give data only for the non-white group and not for the U.S. black population. While the differences between these two groups are small, as shown above for the overall cancer mortality, this cannot be assumed for all cancer types. It is well known, for instance, that cancer of the nasopharynx is more frequent in American Chinese and cancer of the gallbladder more frequent in American Indians than in other racial groups. Therefore, it would be most desirable to have cancer mortality rates for each of the sub-

3 ~~ ~. ~~ ~~~...~.. No. 4 CANCER MORTALITY IN NEGROES 0 Henschke et al. 765 TABLE 2. Trend of the Non-white and White Mortality Rates far the Most Frequent Cancers, (From Data from Report 33 of the National Cancer Institute) Average yearly Trend ICD number Cancer type Sex Death in 1967 change per 100,000 Non-whites Whites Confidence level Group I 170 Increase 153 significantly 177 slower in whites ~~ Lung Lung 199* Other Kidney Tongue Breast Colon Prostate Colon Pancreas Ovary Pancreas Bladder Esophagus Biliary + lilrer Biliary + liver Bladder Larynx Pharynx Multiple myeloma Multiple myeloma Corpus uteri Esophagus Mouth unspec. F 27,985 F M M 15,205 M 9,696 F 9,168 F 7,190 M M F 3,790 M F 2 ; 743 M 2,468 M M 2j081 F 1,798 F F M , P , ,006-0, M 27, M 18,294 0, M 12, P50.01 M 3, M 1, Leukemia M ~. 144 ~~~ Lung F- J is Kidney F 2, ,004 P Pharynx F Conn. tissue F * Other Group I I 151 Stomach Decrease 151 Stomach significantly 154 Rectum faster in whites 191 Skin 191 Skin F 11,180-0, M 10,396-0, F 6, P M 5,836-0, M 1,169-0, F 683-0, Bone M 1, Thyroid F ,015 P Rectum F 4,595-0,092-0,128 P Group Leukemia F 6, No statistically 193 Nervous system M 4, significant 162 Lung F 3, difference 193 Nervous system F 2,988 0, Lymphorsarcoma M 2, Hodgkin s disease M 2, Lymphosarcoma F 1, Hodgkin s disease F 1, P> Other gyn. F 805-0, Conn. tissue M Testis M 682 0, Reticuloses M Reticuloses F Thvroid M Group IV 174 Uterus unspec. F 3, Decrease P 5 0,001 significantly - - slower in 171 Cervix F 7, whites P Group V 190 Malignant melanoma M 1, Increase 190 Malignant melanoma F 1, P significantly ~- faster in whites Ret. cell sarcoma M 1, Ret. cell sarcoma F 1, P * Includes ICD numbers 156, 165, 195, 198, and 199.

4 766 C,ANCER April 1973 Vol. 31 groups, which make up the non-white groups in the United States. Since the other nonwhites have a lower cancer mortality than blacks, it is likely that cancer mortality for most cancers (except nasopharynx and gallbladder cancer), shown in Table 2, is slightly higher for the black group than for the nonwhite group. We hope to obtain the data for blacks in the future. For the time being, the data for non-whites may be taken as a slight underestimate of the black cancer mortality rates, except for nasopharynx and gallbladder cancer. Table 2 is divided into five groups according to the relative tiend of the non-white and white cancer mortality rates. In each group, the cancer types are ranked first according to the statistical significance between the nonwhite and white trend, and second, according to the number of cancer deaths in The figures are the average yearly changes in the age-adjusted mortality rates per 100,000 as determined by Burbank by linear regression analysis.1 The statistical significance of the differences of the trend of the non-white and white mortality rates for the various cancers are also taken from the same report. Group I: All cancers for which the average non-white mortality rate decreased significantly slower in whites than in non-whites. This group contains 29 of the 58 sex-specified cancer types and accounted for 210,094 cancer deaths, or 67.6% of all cancer deaths in It includes the most fiequent cancers, such as cancer of the lung, colon, breast, prostate, and pancreas. Group ZZ: All cancers for which the average mortality rate decreased faster in whites than in non-whites. This group includes male and female stomach cancer, a male catchall group of other unspecified sites and secondary neoplasms (International Classification of Diseases numbeis = I.C.D. 156, 165, 195, 198, and 199), male rectum cancer, male and female skin cancer, male bone cancer, female thyroid cancer, antl female rectum cancer. The nine cancers in this group caused 37,482 deaths or 12.17, of all cancer deaths in Group Ill: All cancers for which there is no statistically significant difference between the trend of tlie white and non-white mortality 1 ates. This group consists of female leukemia, male nervous system cancer, female lung cancer (ICD 162), female nervous system cancer, male lymphosarcoma, male Hodgkin s disease, female lymphosarcoma, female Hodgkin s dis- ease, the female catch-all group of other unspecified sites and secondary neoplasms, male connective tissue cancer, testis cancer, male antl female reticuloses, and male thyroid cancer. The 14 cancers in this group caused 27,806 deaths or 8.9% of all cancel deaths in G~oirf~ IV: The two cancers for which the average mortality rates decreased significantly faster in non-whites than in whites They are unspecified cancer of the uterus (ICD 174), and cancer of the cervix of the uterus (ICD 171). The two cancers in this group caused 11,354 deaths or 3.7%, of all cancer deaths in GI oup V: The four sex-specified cancer types for which the aveiage mortality rate increased significantly faster in whites than in non-whites. They are male and female malignant melanoma and male and female reticulum cell sarcoma. The four cancers in this group caused 5,186 deaths or 1.7y0 of all cancer deaths in COMPARISON OF THE TREND OF MORTALITY RATES AND NUMBER OF DEATHS This study of the mortality rates for all cancers, as well as for tlie 58 most frequent U.S. sex-specified cancer types, confirms the conclusions from our previous study, in which we analyzed the trends of cancer deaths from 1949 to Both studies show clearly the alarming overall increase of cancer in blacks compared to whites and are in good agreement for the most important cancer types. One difference between our two studies is that our new analysis shows that the mortality rates for cancer of the cervix and for cancers in the heterogeneous group, I.C.D. 174, (uterus unspecified, which contains many cancers of the cervix) are decreasing faster in blacks than in whites. In contrast, our previous analysis showed that cancer of the cervix is decreasing faster in whites than in blacks. The discrepancy is due to the fact that we are contemplating the absolute changes (Table 2), while in our previous study we used percentage changes. When the yearly percentage change in the cervix mortality rate is calculated relative to 1950, we find that cancer of the cervix is decreasing faster in whites than in blacks in agreement with the findings in our previous study. Our new study also provides interesting information for a few less common cancers,

5 No. 4 CANCER MORTALITY IN NEGROES - Henschke et al. 767 which were not considered in our previous study of cancer deaths. The new findings are thar there are no significant differences in the trends of the non-white antl white mortality rates for cancer of the testis, for the reticuloses in both sexes, and for thyroid cancer in the male, antl that the rates of the average yearly incieases in mortality were faster in whites than in non-whites in both sexes for malignant melanoma and reticulum cell sarcoma. REASONS FOR RAPID INCREASE OF THE BLACK CANCER MORTALITY RATE In examining the reasons for the alarming rise of the black cancer mortality rates, we will first discuss whether the federal statistics contain major errors. The two most important considerations in this respect are the underreporting of cancer in death certificates and the errors in the census enumeration. Next, we will consider the influence of genetic differences, of age differences, of differences in cure rates, and of environmental factors. Undeweporting of cancer in death certifiratcs: Underreporting of cancers occurs with poor medical care as recently shown by Waggoner and Newell.9 This might have been the reason that, before 1950, the black cancer mortality rate was lower than the white cancer mortality rate. However, underreporting due to poorer medical care cannot explain why the cancer mortality rate in blacks is now 18% higher than in whites. Clearly medical care is not better for blacks than for whites. Eri-oi-s in the census eniimeration: Underenumeration of a racial subgroup in the U.S. census inflates its cancer mortality rate. Spiegelman? estimated that the underenumeration in the U.S. census is 1.3%, but that young black males may be underreported by as much as 7%. However, to cause the rapid rise of the black cancer mortality, the underenumeration would have to increase as rapidly iis the cancer mortality rate, i.e., by an improbable 1% per year. Errors in census enumeration appear to change little and cannot produce the documented rapid rise of black cancer mortality rate. Age differences: All mortality rates in this report are age-adjusted to the age distribution of the total 1960 U.S. population. Age differences between the black and white population are therefore taken into account. Nevertheless, major changes in the relative age distribution of the black or of the white population from 1950 to 1967 could make age adjustments unreliable. A check of the census data reveals, however, that there has been no substantial diift. The percentage of persons over 50 years was 167, in 1950 and 17y0 in 1967 for the black population and 2Zyo in 1950 and 25y0 in 1967 for the white population. Differences in age, therefore, can not be responsible for the alarming increase of the black cancer mortality rates. Genetic differences: The most striking example for genetic differences between the black and white population is cancer of the skin which in the U.S. is extremely rare in blacks. It also appears likely that the large differences in the black and white mortality rates for cancer of the brain, eye, and testis, for malignant melanoma, for the malignant lymphomas, and for the leukemias are at least in part due to genetic differences. For cancers in which environmental factors play a major role, little is known about the genetic differences in black5 and whites. While genetic factors are important, it is obvious that the genetic make-up of any population cannot change much in the span of one generation. Genetic factors, therefore, can not explain the rapidly divergent trend of the black and white mortality rate from 1950 to Cure rates: Cure rates directly influence mortality rates. A rough estimate of the overall cure rate of blacks and whites can be made on the basis of the 1969 Incidence Statistics of the Third National Cancer Survey5 and the 1967 Rlortality Statistics. If one assumes that the cancer cure, incidence, and mortality rates are in a steady state, one obtains overall cure rates of 37y0 for blacks and of 45% for whites. From more than 20 years of personal treatment of black and white cancer patients, it is quite evident to the three clinicians in our group that the cure rates in black cancer patients are considerably lower than in white cancer patients. However, as in the case of the other factors, the trend in the cure rates between 1950 and 1967 for blacks and whites are not different enough to explain the divergent trends of the black and white cancer mortality rates between 1950 and Environmental factors: Obviously all the above listed factors have some influence on cancer mortality rates and deserve closer study in the investigation of racial differences. However, it seems that these factors are insufficient to explain the different trends of the black

6 768 CANCER April 1973 and white cancer mortality rate over the 18- year period from 1950 to This leaves environmental factors as the most likely reason. That environmental factors can cause a rapid change of cancer mortality rates can be readily documented. Lung cancer for instance, which shows by far the fastest increase in mortality rates, is causally related to increase in cigarette smoking. The rapid decrease of stomach cancer in the U.S. is another convincing example of the great influence of environmental factors. The magnitude of the change of the black mortality rate is thus entirely compatible with changing environmental factors. Many different environmental carcinogens are probably involved. Exposure in industry may be important. Many of the jobs with the greatest exposure to health hazards are now filled by blacks. Food habits also have changed rapidly in the span of one generation in blacks, while the same changes took much longer in whites. Cigarette smoking seems to have increased much more rapidly in blacks than in whites since 1930, and this might be the main cause for the more rapid increase of lung cancer and perhaps of bladder cancer. Increasing alcohol consumption might be connected to the rapid rise in intra-oral, esophagus, and liver cancer. In summary, on the basis of this admittedly very preliminary analysis, we feel that environmental factors could well explain the marked changes in the black cancer mortality rates between 1950 and IMPLICATIONS Vol. 31 The alarming increase of the black cancer mortality rates has many serious implications. 1. Cancer management is so difficult and time consuming that the already overloaded and understaffed facilities for medical care of black patients will be put under a severe strain by an increase of black cancer patients of about 5Yo per year. 2. Few black families have the economic resources which are required for optimal cancer care. Economic assistance is required to make it possible for black cancer patients to follow a proper therapeutic program. 3. The increase in black cancer mortality does not show any indication of flattening out. In fact, in some cancers, the trend seems to be accelerating, and plans should be formulated to cope with the expected further rapid increase in black cancer patients. 4. Racial differences in cancer incidence antl mortal; ty shoiild be thoroughly studied. This has not been done in the past, and the rapid increase in black cancer mortality has escaped attention, although it could have been easily spotted from the Official Statistics of the United States as far back as An investigation of the more rapid change of cancer mortality rates in blacks makes it more likely that environmental carcinogens can be identified. Epidemiological studies in blacks appear especially promising. The results would be applicable, of course, to the prevention and cure of cancer in all races. REFERENCES 1. Burhank, F.: Patterns in canccr mortality in the United States, Null. Cancer Inst. Monogr. 33: C1.S. (;overnment Printing Office, M ashington, D.C. 2. : Males tlominate once again: U.S. cancer mortality. A. EngI. 7. Med.?85: Fontainc, S., Henschke, I T., Leffall, L.. Mason, C.. Reinhold,.4., Schneider. R., and White, J.: Comparison of the cancer deaths in the hlack and white U.S.A. population from 1949 to Med Ann. D. C. 41: , Krain, I.: The rising incidence of carcinoma of the pancreas. Am.,J. Gnstroenterol. 54:500, National Cancer Institute: Third National Cancer Survey, Incidence Preliminary report. G. Seitlman, H.: Cancer death rates by site and sex for I-eligions and socioeconomic groups in New York City. Enr~iroii. Res. 3: , Spicgelman, M.: Introduction to Demography. Camhritlge, Mass., Harvard University Press, J.S. Department of H.E.W., Public Health Service: Official Vital Statistics of the CJ.S.A., Washington. D.C., ITS. Government Printing Office. 9. Waggoner, D., and Newell, G.: RegionaI convergence of cancer mortality rates over time in the United States. 194C Am. J. Epideiniol. 93:79-83, Wvntler, E., Mahuchi. K.. antl Whitemore, W.: Epidemiology of cancer of the prostate. Cancer 28: , 1971.