In 1851, the U.S. Census Bureau recorded the number of people who had cancer in the U-S.
at 3.3 million.
That was way up from the earlier peak of 1.3 percent in the late 1890s, when the nation’s population was less than 2 million.
“It’s pretty amazing to think that the population of the United States had just barely come into existence when we recorded that, in 1851,” says Robert S. Gorman, an epidemiologist at the University of California, Berkeley, and the author of The Cancer Sign: The History of the Diagnosis of Cancer.
As the number and types of cancer grew, so did the need for accurate data about it.
The first cancer-related census was conducted in 1880, and by 1910, the country was on track to record more than 5 million new cases of cancer a year.
By the mid-1920s, more than 40 percent of Americans had a diagnosis of cancer, and for the first time, nearly half of them were living with the disease.
And the disease’s spread — the more people got it, the more they were at risk — continued to increase.
But while that wave of epidemics swept through the country, the disease itself was still not well understood.
The early data, compiled by the Ulysses S. Grant Cancer Research Center at the National Institutes of Health in the early 1930s, showed that the incidence of cancer was increasing in some states.
But the disease did not show up in the national population statistics until the 1950s, with the first official national survey.
The data collected in the mid-’50s suggested that the cancer was spreading at a rate that was increasing, but it wasn’t clear why.
That survey also revealed that the first cancer cases were concentrated in a few states: In the District of Columbia, for example, just 7 percent of the patients were diagnosed with cancer, compared with nearly 80 percent of people in the country.
“We knew that it was an underdiagnosis, but what we didn’t know is why,” Gorman says.
It wasn’t until a decade later, with another survey of Americans, that researchers were able to get a better picture of the cancer epidemic and the reasons for it.
“A lot of this information was hidden from us,” Gromans says.
And so, for the past 20 years, he and his colleagues have been trying to figure out how this new data came to be.
In their new book, The Cancer-Cancer Sign: A Statistical Study of the History of Cancer in the United State, the authors point out that the survey of American patients was done between 1940 and 1970.
By then, the national incidence of the disease was well established, but the survey also allowed researchers to trace the growth of the population, and to compare that growth with the rate of change in the cancer rate.
The authors then analyzed the data, comparing the national numbers with the rates of change for each state.
They found that in states where there were more cancer cases, the number grew faster than in states that experienced fewer cases.
And, the data showed, states with higher incidence of patients with cancer had higher rates of growth in the incidence and growth in cancers of the general population.
“When we looked at cancer incidence, we didn’st see a correlation,” says Michael H. Mink, a researcher at the Department of Health and Human Services at the American Cancer Society in Bethesda, Maryland.
But when the researchers compared the rates in states with a higher incidence with those in states without one, they found a relationship.
“The correlation between the incidence rate and the change in cancer was striking,” Mink says.
That relationship could not be explained by a difference in the way cancer patients and those without cancer were treated.
The only way that this relationship could be explained was through the effects of the epidemic.
In the late 1950s and early 1960s, for instance, there were outbreaks of new cancer infections in the Midwest, particularly in the cities of Detroit and Chicago.
And as more of those new cases were diagnosed, the incidence in those cities spiked, and more people became infected.
But as the epidemic spread, so too did the incidence, according to the researchers.
And by the mid ’60s, a number of factors had contributed to the increase in cancers in these cities, including more people living in those areas and fewer doctors in those places.
“If we looked for the cause of the increase, we couldn’t find it,” Gormans says, noting that even though it was a national epidemic, the causes were local.
“That would suggest to us that this was a local phenomenon,” he says.
But he and others weren’t convinced.
“For a long time, it wasn’t really understood that this epidemic was not local,” Mok says.
The problem was that there were too many variables in the data collected, and they weren’t consistent