Recent research from a team at the University of Cambridge has looked into the historical prevalence of cancer. It is frequently assumed that cancer rates are higher today than they were in the past due to a combination of modern carcinogens and our longer lifespan, but is this actually true? The researchers aimed to find out.
There are surprisingly few studies on cancer rates in history, which may be due to a lack of obtainable evidence. While cancer is known to have affected humans for millennia, it is likely that only advanced or severe cases would have been apparent before modern diagnostic techniques, meaning that any documentary evidence of cancer would be incomplete and incomparable with today’s definitions. Palaeopathological evidence offers one way of being able to assess cancer levels in the past, however. Through radiographs and computed tomography (CT) scanning of human skeletons, cancerous lesions can be accurately identified, and while this, of course, only detects cancers that affected the bones, by comparing the number of modern cases in which metastases affect the skeleton, an overall rate can be estimated.
It is this approach that was used by the Cambridge team, who assessed 143 skeletons from six different cemeteries in and around Cambridge, ranging in date from the 6th through to the 16th century. By scanning the bones of each individual – paying especially close attention to the pelvis, spine, and upper legs, as these are the bones most often affected by malignancies – the team was able to identify potentially cancerous lesions, including ones that could not be determined through visual analysis alone.
Overall, they identified five individuals with evidence for cancer, indicating a minimum prevalence of 3.5%. As modern clinical studies show that CT scans are approximately 75% effective at detecting bone metastases, this means that the true prevalence of bone lesions among this assemblage might be closer to 4.7%. To extrapolate this number further, in modern cases, about one-third to one-half of people who die with cancer have bone lesions, meaning that in medieval Cambridge the minimum prevalence of cancer may have been between 9% and 14% of adults. This rate is significantly lower than modern data, which shows that between 40% and 50% of people in Britain have cancer at time of death, but it is higher than was previously thought. So, while modern carcinogens and our extended lifespan probably have had an effect on our cancer rates, a not-insignificant percentage of people in the past also suffered from the disease.
Looking more closely at the data, all those identified with bone metastases were middle-aged to elderly men, and most of the lesions were found in the pelvis. While in most cases the origins of the cancer could not be determined, one man from the Edix Hill cemetery – an Anglo-Saxon burial ground located in Barrington just outside Cambridge – had small lesions throughout his skeleton, which the team believes is consistent with multiple myeloma. Because the sample size was relatively small, further differences between demographics could not be determined. The research has shown this to be an effective way to assess cancer in the past, however, and it is hoped that in the future larger-scale studies may be able to use this method to show more detailed patterns and prevalence rates.
The results of this research were recently published in the journal Cancer and can be read for free here: https://doi.org/ 10.1002/cncr.33615.