A 4,000-year-old Egyptian skull, stored at the University of Cambridge, has been hiding almost imperceptible cut marks for decades.
Now a new study published in Frontiers in Medicine suggests these could be evidence of an ancient treatment for cancer.
The find shows that Egyptian medicine was both advanced and sophisticated, said author Edgard Camarós, a palaeopathologist from the University of Santiago de Compostela in Spain.
"This research has found a clear milestone in the history of medicine," Dr Camarós said.
"More than 4,000 years ago they were trying to medically manage what we nowadays call cancer."
However, questions remain over whether the tiny cuts show cancer treatment, or an ancient post-mortem investigation.
Despite our modern increase in life span, cancer is not exclusively a 20th and 21st century phenomenon.
The oldest known evidence of cancer was discovered in the toe bone of what researchers believe was a species of ancient human called Homo ergaster from 1.7 million years ago.
And a 2005 study found the incidence of cancer in ancient Egyptian and German populations was not much lower than we see today.
In that study, the researchers found evidence of five tumours in 905 ancient Egyptians buried in three separate necropolises between 3200 and 500 BC.
They then found 13 cases in 2,547 people buried in a Southern German ossuary between AD 1400 and 1800.
As seen in the graph below, scaled up to cases in 100,000 people, this is not far off the rate of new cancer diagnoses in Australia in 2023.
This may also be just the tip of the iceberg.
Cancer can occur in soft tissue or bone, but soft tissue decays unless a body is mummified, and while some ancient Egyptians underwent this process, it was reserved only for the rich and those deemed important.
This is why researchers generally only look for evidence of cancer in ancient humans in bone.
And this could skew what we see, said Ronika Power, a bioarchaeologist from Macquarie University, who was not involved in the new study.
"It has been upheld ... that the incidence of cancer is lower compared to modern rates, due to reduced human-made carcinogens in the environment, and the fact that life expectancy was generally shorter," Professor Power said.
"However, we are limited to observing diseases that were chronic or specific enough to affect bone."