Cancer incidence rates in the developed world are increasing each year and developing countries are also now showing an increased incidence of the disease.
But how much were our ancestors affected by the disease? Dr Mario Slaus of the Croatian Academy of Sciences and Arts in Zagreb presented archaeological findings at the 18th Meeting of the European Association of Cancer Research (EACR-18) in Innsbruck today (6 July 2004), suggesting that the disease was very uncommon even in our recent ancestors, reinforcing the concept that cancer is a ‘modern’ disease and is largely a consequence of the greater longevity we are now experiencing.
Dr Slaus and his colleagues1 analysed the skeletal remains of the 3,160 individuals in the Skeletal Collection of the Croatian Academy of Sciences and Arts for evidence of neoplasms (uncontrolled and abnormal tissue growth). The remains in the collection date from 5,300BC to the 19th Century AD and have been collected from archaeological sites across Croatia. Analysis (including gross morphology, X-rays and CT-scans) revealed 4 cases of neoplastic disease in individuals ranging from 3-4 years to 50-60 years of age. All 4 cases involved bone neoplasms (obviously, as bone was the only tissue remaining): two fibrous cortical defects, an osteochondroma and an osteoma. All three conditions were benign, with little potential for malignant transformation.
“The low frequency of neoplasms in the Croatian Skeletal Collection is characteristic for archaeological material”, said Dr Slaus. “We found no evidence of secondary bone tumours in any individual in the collection, a factor that is probably explained by the fact that the mean age-at-death of the specimens is 35.6 years. Primary malignant and benign tumours of bone are relatively rare, even in young individuals where the incidence of these neoplasms is highest, whilst secondary tumours of bone, although much more common, are associated with older age”.
Life expectancy in the 21st Century is higher than it has ever been in the past; a consequence of a range of factors such as better nutrition, improved health awareness in the population, better sanitation and more accessible healthcare. However, increased longevity is accompanied by an increased incidence of cancer. The factors most clearly correlated with the development of cancer in the European Union are smoking (estimated to cause 30% of all cancer deaths) and obesity / dietary factors (estimated to be responsible for a further 30% of all cancer deaths) but these factors often take many years to lead to the development of symptomatic tumours, so aging populations naturally show a higher incidence of the disease.
“The individuals in the Croatian Skeletal Collection would have been prone to diseases such as syphilis, tuberculosis and leprosy (and we found evidence for each of these conditions in individuals in the collection) and these illnesses (and others) would certainly have contributed significantly to mortality in our ancestors”, added Dr Slaus.
“The change from these ‘old’ illnesses to ‘modern’ ones such as cancer can be seen as part of the evolution of our society, but as with the ‘old’ illnesses we can go some way to combating the ‘modern’ illness of cancer through educating people about the risks of the disease and encouraging them to adopt a healthy lifestyle”, said Dr Slaus.
The Croatian Skeletal Collection demonstrates how cancer is, in large part, a consequence of our recently significantly increased life-span, as well as significant changes to our lifestyle. The incidence of cancer we currently have in Europe, and the increasing incidence being seen in the developing world, can be reduced significantly through greater education about the benefits of not smoking tobacco, by encouraging people to eat a diet plentiful in fresh fruit and vegetables, through the promotion of a lifestyle that includes regular exercise and by encouraging people not to drink alcohol to excess.