Why are ancient tumours rare?
It has been suggested that the short lifespan of individuals in antiquity precluded the development of cancer. Mortality tables are not available for ancient populations; in fact, even total population figures are largely estimates, and standardized epidemiological studies are lacking38. However, there is conclusive evidence from ancient Egypt, for example, that the average life expectancy of the whole population, over a period from c.4000 BCE to c.400 CE, was much lower than in contemporary society. Information about an individual's life and career that is provided by tomb and coffin inscriptions, together with the palaeopathological evidence, confirms that the average lifespan of the wealthier classes was between 40 and 50 years, and a lower age-at-death of between 25 and 30 years is shown in palaeopathological studies of non-elite groups. Although life expectancy was statistically lowered by infant and maternal mortality and infectious diseases, many individuals did live to a sufficiently advanced age to develop other degenerative diseases, such as atherosclerosis39, Paget's disease of bone40 and arthritis41. As recently as fifteenth century England, life expectancy was 50 years for males and 30 years for females42. It must also be remembered that, in modern populations, tumours arising in bone primarily affect the young, so a similar pattern would be expected in ancient populations. Therefore, the rarity of tumours in ancient populations could be a result of factors other than life expectancy.
Another explanation for the rarity of tumours in ancient remains is that tumours might not be well preserved; however, experimental studies43 show that mummification preserves the features of malignancy (Fig. 2). In an ancient society lacking surgical intervention, evidence of cancer should remain in all preserved specimens. Although the palaeopathological diagnosis of cancer is subject to many difficulties7, we propose that the minimal diagnostic evidence for cancer in ancient remains indicates the rarity of the disease in antiquity. Carcinogenic environmental factors have been linked to up to 75% of human cancers44, and the rarity of cancer in antiquity suggests that such factors are limited to societies that are affected by modern lifestyle issues such as tobacco use and pollution resulting from industrialization45, 46.