for National Geographic News
A new study of over 3,000 human skeletons in a Croatian archaeological collection suggests that cancer is more common today than at any point in humankind's history, the report's authors say.
A team of Croatian archaeologists and medics studied ancient human remains dating from 5,300 B.C. to the mid-19th century. The bones, which came from 21 archaeological sites scattered around the eastern European country, are stored at the Skeletal Collection of the Croatian Academy of Sciences and Arts in Zagreb.
Examining the ancient skeletons, researchers found scant evidence of the telltale imprints that some cancers leave.
"While cancer is the number one or two killer in most developed countries today, it was very rare in antiquity," said Mario Slaus, who led the study. Slaus is an anthropologist with the department of archaeology at the Croatian Academy of Sciences and Arts.
"Archaeological populations had little to fear from cancer," he said. "Other infectious diseases where significantly more likely to result in death or affect their quality of life."
Slaus and his colleague presented their study's findings at a meeting of the European Association of Cancer Research in Innsbruck, Austria, earlier this month.
The researchers argue that cancer is more common today because people now have much longer life spans than they did just a few centuries ago. In Croatia, for example, the current average life expectancy is around 74 years. But the average age of death found in the archaeological remains that researchers studied was just 36 years.
Longer human life spans enable slow-developing cancers to appear.
The cancer rate in both the developed and developing world continues to increase year by year.
Most cancers are restricted to organs and other soft tissues, but several types leave evidence in the skeleton. While primary tumors of bone, which develop initially in the bone itself, are rare today, secondary metastatic bone tumors are relatively common.
These secondary bone tumors occur when cancers in other soft tissues migrate and form tumors, or metastasize, in the skeleton. They are often found in people who develop cancer later in life.
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