Epidemiologic Statistics

The statistically inclined reader may wish to follow the authors through the methods used to derive the data presented in the epidemiology sections throughout this book. It must be realized that these statistics are to serve as a simple guide to the scope of the cancer problem and that, as such, the figures and percentages have been approximated and certain arbitrary decisions made as to content.

Incidence, Mortality, And The Rates And Ratios By Sex

These figures are derived from the American Cancer Society estimates published in the 1961 Cancer Facts and Figures.

Age

Two sources were used: actual 1959 incidence and mortality rates by five-year age spans from New York State (exclusive of New York City) and actual 1959 mortality rates from the United States Bureau of Vital Statistics. The category called '"significant increase" indicates a rate of 5 or more per 100,000.

Trend Last Ten Years

The same sources used for "age" were used to determine these trends.

We used certain arbitrary guidelines in the interpretation of trends. For instance, if a disease had a rate of 2 per 100,000 in 1950 and 3 per 100,000 in 1960, this represents an increase of 50% in the ten-year period, which appears significant from a percentage standpoint but is, in actuality, insignificant numerically. As a result, to merit inclusion in this section, the base figure had to be either (1) substantial enough to show a statistically significant increase, or (2) when based on a small number of cases, the percentage increase had to be so striking that it became significant in the over-all picture. Where the figures failed to meet one or the other of these criteria, the phrase "no significant change" was used.

Geographic Distribution

All data for foreign countries were obtained from Segi, M.: Cancer Mortality for Selected Sites in Twenty-Four Countries (1950-1957), Sendai, Japan, 1960, Tohoku University School of Medicine.