This article is the Daily Mail's take
on this perspective piece in Nature Reviews Cancer. The latter is not
in the public domain but should be freely available if you have
access via an academic institution or large library. Perspective
pieces are not subject to the same kind of scrutiny as research
articles and offer a space for opinion, reflection and the airing of
controversy. The authors are palaeopathologists with, as far as I can
ascertain from PubMed, no publication record in epidemiology or
cancer biology.
The perspective piece presents an
overview of studies on mummified Egyptian remains, claiming « a
scarcity of cancer in the earliest remains » reflects a low incidence of cancer in the sample population. As the authors
are doubtless aware, absence of evidence is not evidence of absence.
Accurate epidemiological data are difficult to obtain in the best of
circumstances. Analysis of a limited number of poorly preserved
ancient specimens is unlikely to furnish it. Further, mummification
was an expensive and time-consuming process – one not all of
ancient Egypt's decedents would have been subject to, depending on
factors including income, status, ethno-cultural group and religious
belief. Mummified specimens are unlikely then to provide a randomised
cross-sectional sample required for plausible epidemiological claims. As the authors admit, « other
possible factors to explain this lack of evidence include the
limitations of the diagnostic methods used by early investigators to
study these remains, and the insufficiency of data to provide a
reliable rate of cancer incidence. » The fact that the authors
offer no quantitative data for their epidemiological assertions renders
them difficult to seriously assess.
The authors seek further evidence of
the ancient scarcity of cancer through literature, claiming « limited
evidence » that ancient Egyptian physicians accurately
diagnosed cancer. Even if this is true (in fact not uncontroversial),
from the fragmentary medical papyri available, this does not
constitute evidence that cancer was rare in antiquity. The authors
admit that in ancient Greek medical texts, tumours were « common
enough to be widely studied and recorded », claiming this
may reflect an increase in incidence or diagnosis. On the supplied
evidence, these conclusions are tenuous.
The article goes on to argue that
lifespan does not adequately explain the (claimed) lower incidence of
cancer in ancient Egypt as mummies show evidence of other age-related
conditions such as atherosclerosis, Paget's disease and arthritis. It
should be noted that these conditions - particularly arthritis, which is almost a uniform age-related finding - have a
much higher rate of incidence than cancers and so are much more
likely to be present in analysed remains.
There is excellent evidence to
demonstrate that environmental factors – some of which are
anthropogenic - such as exposure to ionising radiation and certain chemical agents increase gene mutation and cancer incidence. This
speculative article is bad science and does not constitute such
evidence.