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.
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