on 26 October 2011
Some 2250 years ago in Egypt, a man known today only as M1 struggled with a long, painful, progressive illness. A dull pain throbbed in his lower back, then spread to other parts of his body, making most movements a misery. When M1 finally succumbed to the mysterious ailment between the ages of 51 and 60, his family paid for him to be mummified so that he could be reborn and relish the pleasures of the afterworld.
Now an international research team has diagnosed what ailed M1: the oldest known case of prostate cancer in ancient Egypt and the second oldest case in the world. (The earliest diagnosis of prostate cancer came from the 2700-year-old skeleton of a Scythian king in Russia.) Moreover, the new study now in press in the International Journal of Paleopathology, suggests that earlier investigators may have underestimated the prevalence of cancer in ancient populations because high-resolution computerized tomography (CT) scanners capable of finding tumors measuring just 1 to 2 millimeters in diameter only became available in 2005. "I think earlier researchers probably missed a lot without this technology," says team leader Carlos Prates, a radiologist in private practice at Imagens Médicas Integradas in Lisbon.
Prostate cancer begins in the walnut-sized prostate gland, an integral part of the male reproductive system. The gland produces a milky fluid that is part of semen and it sits underneath a man's bladder. In aggressive cases of the disease, prostate cancer cells can metastasize, or spread, entering the bloodstream and invading the bones. After performing high-resolution scans on three Egyptian mummies in the collection of the National Archaeological Museum in Lisbon, Prates and colleagues detected many small, round, dense tumors in M1's pelvis and lumbar spine, as well as in his upper arm and leg bones. These are the areas most commonly affected by metastatic prostate cancer. "We could not find any evidence to challenge this diagnosis," Prates says.
"I would agree that it's a case of metastatic prostate cancer," says Andreas Nerlich, a pathologist at the Academic Hospital Munich-Bogenhausen in Germany, who was not involved in the research project. "This is a very well-done study."
Researchers have long struggled to detect evidence of cancer in the skeletons and mummified flesh of the ancient dead. But recorded cases of cancer in ancient populations are rare. Indeed, one study published in 1998 in the Journal of Paleopathology calculated that just 176 cases of skeletal malignancies had been reported among tens of thousands of ancient humans examined. The low number of cases prompted a theory that cancer only began flourishing in the modern industrial age, when carcinogens became more widespread in food and in the environment and when people began living longer, giving tumors more time to grow and proliferate.
But ancient populations, says Albert Zink, a biological anthropologist at the Institute for Mummies and the Iceman in Bolzano, Italy, were no strangers to carcinogens. Soot from wood-burning chimneys and fireplaces, for example, contains substances known to cause cancer in humans. And the bitumen that ancient boat builders heated to seal and waterproof ships has been linked to lung cancer as well as tumors in the respiratory and digestive tracts. "I think cancer was quite prevalent in the past," Zink says, "more prevalent than we have been able to see."
But that situation may be changing, Prates says, as physical anthropologists gain access to the new generation of high-resolution CT scanners. The equipment that Prates and his colleagues used to study M1, for example, has a pixel resolution of 0.33 millimeters, allowing radiologists to visualize even fleck-sized lesions.
For scientists studying the origins of cancer and the complex interplay of environment, diet, and genes on the prevalence of the disease, such improved detection could shed new light on a disease that has plagued humanity for many thousands of years, if not longer. "And for sure there's always the hope that reaching a better understanding of the roots of cancer will help contribute in some way to a cure," Zink concludes.