Cancer is quite often referred to as a modern “scourge of mankind” — not unreasonably as it kills about 10 million a year. Heart diseases cause slightly more deaths though there’s not a lot in it. But an interesting question is whether cancer really is “modern”. If the answer is “yes” then we have to conclude that it’s our fault, generated by self-inflicted changes over the last century or so. If “no” we can blame it all on nature. As ever, the answer turns out to be a bit of both.
Ancient Egyptians
We’ve known since a papyrus bought by an American called Edwin Smith on a visit to Luxor in 1862 was translated in the 1920s that cancers afflicted the ancient Egyptians around 1600 BCE. In the 1970s Professor Rosalie David at the University of Manchester launched the Manchester mummy project that started applying the most modern techniques to screening preserved corpses for signs of tumours. In the intervening 50 years several other projects have employed computed tomography scanning techniques (CT scans) and scanning electron microscopy (SEM) to analyse mummies. Taken together this medical archaeology has revealed the world’s oldest known cases of breast cancer, prostate cancer and multiple myeloma (a type of bone marrow cancer) and also of metastatic carcinoma.
In a recent complement to the Edwin Smith papyrus, in 2018 archaeologists unearthed six bodies bearing signs of cancer in Egypt’s Western Desert. These included a toddler with leukemia and a mummified man in his 50s with bowel cancer. These intrepid anthropologists estimated that the lifetime cancer risk for those Egyptians was about 5 in 1,000, compared with nearly one in two in modern Western societies.
Even More Ancient Fossils
All that, however, has been spectacularly upstaged by some palaeontologists who, ferreting around in a field in what is now Germany, stumbled over the remains of a turtle who had been stricken with a kind of bone cancer common in humans today. Almost incomprehensibly, this reptile’s tumour-bearing, fossilized femur turned out to be 240 million years old!!
240 million years of cancer. Right: the fossilized femur of the shell-less stem-turtle Pappochelys rosinae (left). An osteosarcoma, a highly malignant bone tumour, is clearly visible near the top of the thigh bone. From Haridy et al., 2019.
Turtles and humans had a common ancestor some 310 million years ago and, taken together, all these diverse findings suggest that cancer has been a constant companion of mammalian evolution. Nevertheless, in humans, a few mummies aside, it’s been difficult to find evidence of cancer in remains of the long dead to the extent that, as recently as 1998, a study published in the Journal of Paleopathology estimated that only 176 bone cancers had been found in tens of thousands of ancient humans. Such a low number is consistent with cancer only becoming prominent in the modern era.
Car Crashes
However, there are a couple of other pieces of evidence that bear on the question of cancer’s modernity. First are autopsy studies on individuals who died in automobile accidents or by other trauma and who had not been diagnosed with cancer when they were alive. These show that a large portion of adults carry microscopic cancers less than 1 mm in diameter — they’re called dormant tumours. We know from the evidence of cancer development than almost none of these would have progressed to clinically detectable disease had they lived a normal lifespan.
Digging Up Cambridge’s Past
The second and most recent contribution has just come from Piers Mitchell and colleagues in the Department of Archaeology at the University of Cambridge. They carried out X-rays and CT scans on the remains of almost 150 skeletons dating from the 6th to the 16th century excavated from six cemeteries in Cambridge and the surrounding area. The range of locations meant that the remains were of rich and poor people, of Augustinian friars and of those who died in a hospital. It’s the first study to use state-of-the-art methods to screen for cancer in a pre-industrial population and the conclusion was that 9 to 14% of adults in medieval Britain had the disease at the time of their death — about 10 times the previous estimate for cancer rates in medieval Britain.
Excavated medieval bone from the spine showing cancer metastases (white arrow). Credit: Jenna Dittmar from Mitchell et al., 2021.
So Which Is It?
It’s clear from all this digging that, far from being a “modern scourge”, cancer has been around as long as we have — ‘we’ being mammals. But this still leaves us with a question. In 1900 the three leading causes of death in the USA were pneumonia, tuberculosis and diarrhea and enteritis, which (together with diphtheria) caused one third of all deaths. In 2019 the leaders were heart disease and cancer. These patterns closely parallel those in the UK and they point to how cancer has risen to become a scourge.
From the 1500s to 1800 life expectancy in Europe was between 30 and 40 years. By 1900 the UK figures had risen to 48 and 52 for men and women, respectively, whilst in the USA the corresponding figures were 46 and 48 years. In 2020 the average figures for men and women were 79 years in the USA and 81.5 years in the UK.
So we have our answer: living conditions in developed countries have so improved over the last century that we’ve almost doubled our longevity. We know that our bodies have cancer built in to them in that both internal and external factors can damage our DNA. This causes mutations that accumulate over time. More than nine out of 10 cancers are diagnosed in people over the age of 45 and age is the biggest risk factor for the disease. Unsurprisingly, therefore, before the twentieth century cancers were comparatively rare — we simply didn’t live long enough for them to show up. They’ve evolved into a scourge as a product of all our good living — helped of course by the ‘self-inflicted’ factors mentioned at the beginning, most notably smoking.
The bottom line is that, knowing the rate that mutations occur, it can be estimated that if we lived to be 140 years old we’d all have cancer. Think about that next time someone offers you an elixir of life!
References
Haridy, Y. et al. (2019).Triassic Cancer—Osteosarcoma in a 240-Million-Year-Old Stem-Turtle. JAMA Oncol., 5, 425-426. doi:10.1001/jamaoncol.2018.6766
Capasso, L.L. (2005). Antiquity of cancer. International Journal of Cancer 113, 2-13.
Betrayed by Nature: The War on Cancer 