CANCER: A WORLDWIDE MENACE

SOME FACTS AND FIGURES ON ITS OCCURRENCE IN THE UNITED STATES AND ABROAD

1. What is cancer?

Cancer is a popular term for malignant neoplasms, a great group of diseases of unknown (and probably multiple) cause, occurring in all human and animal populations and arising in all organs and tissues. The malignant cells lack the usual controls over their growth and function. As a result, they invade adjacent tissue and spread to distant parts of the body, with serious adverse effects to the individual. There are important differences in the occurrence of neoplasms by type and by site, not only from species to species but even within human populations. The distribution of specific types of cancer is influenced by a variety of factors including age, sex, race and place of residence, habits, and occupation. The latter three presumably reflect differences in exposure to environmental factors which initiate or stimulate the development of cancer.

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2. How important is cancer as a cause of death?

In most countries having reliable death figures, cancer is now the second leading cause of death. This is true for the United States, Canada, most of Europe, Australia, and New Zealand. It is apparently also true for the U.S.S.R. The figure shows the increasing importance of cancer as a cause of death in the United States between 1900 and 1955.

For countries with less reliable statistics, the infectious diseases normally account for a high proportion of the deaths. However, autopsy information from some of these countries indicates an unusual amount of cancer for certain specific sites-always of great interest to investigators. (Source: WHO; Annual Epidemiological and Vital Statistics Report, 1954.)

CANCER ASSUMES INCREASING IMPORTANCE
AS A CAUSE OF DEATH

(RATE PER 100,000 POPULATION)

3. Is the frequency of cancer increasing?

In those countries with a long series of fairly reliable death figures, the number of cancer deaths has shown an increase. In most instances it is moot whether any part of this represents a real increase in the risk of dying from cancer. Part of it reflects increasing populations. Part reflects the conquest of communicable diseases, which has allowed a larger proportion of people to survive to older ages, where cancer is more common. Part reflects an increasing awareness of cancer and improving diagnosis.

For two countries, at least, the United States and England and Wales, many informed observers feel that there has been a real increase in the risk of dying from cancer. (Source: WHO; Epidemiological and Vital Statistics Report, vol. 5, pp. 1-144, 1952.)

FACTORS ACCOUNTING FOR THE INCREASING NUMBER OF CANCER DEATHS, ORIGINAL DEATH REGISTRATION STATES, UNITED STATES, 1900-1954

(THE DEATH REGISTRATION AREA OF 1900 INCLUDED THE DISTRICT OF COLUMBIA AND 10 STATES: MAINE, NEW HAMPSHIRE, VERMONT, MASSACHUSETTS, RHODE ISLAND, CONNECTICUT, NEW YORK, NEW JERSEY, MICHIGAN, AND INDIANA)

4. Will cancer become more common in the future?

Unless there are fundamental changes in the risks of developing cancer and dying from it, the growth of the population and the increasing proportion of older persons will result in an increasing number of cancer cases and cancer deaths. Thus, when the population of the United States reaches 200 million-in 1975, by conservative estimates-there will be more than a million cancer cases under treatment and 325,000 people will die each year from cancer. Should the risk from lung cancer continue to rise in this country (and the trends for other countries suggest that it will) these estimates will, in fact, prove to be too low. (Source: Cutler, S. J., and Haenszel, W. M., "The Magnitude of the Cancer Problem," Public Health Reports, vol. 69, pp. 333-339 (1954).)

ESTIMATED NUMBER OF NEW CANCER CASES EACH YEAR, UNITED STATES, 1940-75

NUMBER OF NEW CANCER CASES (thousands/year)

5. What is the probability that a person will develop cancer?

At birth the chances of developing cancer in a lifetime are one in five for men and one in four for women. These estimates are based on experience from New York State and assume that both cancer incidence and mortality from other causes remain fixed at their present level.

The chances of developing cancer vary with age. They are, for example, greater at age 20 than at birth. At older ages, however, the competition of other chronic diseases begins to be felt and by age 65 the chances of developing cancer in the lifetime remaining are less than they were at birth.

The chances of developing cancer also vary by site. For men, the lifetime probability of developing cancer is greatest for the skin and prostate. For women it is greatest for the breast and large intestine. Of all the sites, the breast in women is the one for which the lifetime probability of developing cancer is greatest. (Source: Goldberg, I. D., Levin, M. L., Gerhardt, P. R., Handy, V. H. and Cashman, R. E. "The Probability of Developing Cancer," Journal National Cancer Institute, vol. 17, p. 163 (1956).)

PROBABILITY OF DEVELOPING CANCER, UPSTATE NEW YORK, 1949-51 30