The abilities to adapt, grow and evolve are usually positive
attributes unless you're talking about human melanocytic
skin lesions. Dermatologists were quick to point out the
need to flag lesions with these dangerous qualities and
have added new criteria to the current guidelines to help
doctors spot the signs.
Twenty years ago, a group of New
York University dermatologists introduced the ABCD criteria
for identifying such lesions, or nevi. The warning signs
are: 'A' for asymmetry — one half of a mole doesn't
match the other half; 'B' for border irregularity —the
edges of a mole are ragged or blurred; 'C' for colour
— an irregular mixture of black, brown, red, white
or purple; and 'D' for diameter greater than 6mm.
E
FOR EVOLVE
While these signs have helped primary care doctors form
a crucial firstline of defence against skin cancer,
their creators have come to regard them as insufficient.
In the December 8 issue of the Journal of the American
Medical Association (JAMA), in collaboration with
Australian colleagues, they set out new guidelines listing
a fifth criterion: 'E' for evolving.
"An evolving lesion is one which
is changing in terms of the five S's — size, shape,
symptoms such as itching or tenderness, surface bleeding,
or shades of colour," explained Dr David Polsky, associate
director of the New York University Department of Dermatology's
Pigmented Lesions Section. "Essentially, a lesion that
significantly changes is a concerning lesion."
It's hardly earth-shattering news
that changing lesions are the most dangerous. Dermatologists
and even non-specialists have been aware for years that
growing or colour-shifting lesions are the ones they
should watch for. But the JAMA authors are particularly
concerned about a subtype of melanoma that may escape
detection completely using the old ABCD criteria.
IN
DISGUISE
Nodular melanoma accounts for slightly less than 15%
of all cases, but it's the most aggressive form of the
disease. Worse, it often fails to match the A, B and
C characteristics associated with precancerous lesions,
bearing more resemblance to a harmless normal mole.
Since melanoma is eminently treatable if caught early,
but deadly once it's metastasized, the stealthy nodular
form accounts for a disproportionate fraction of melanoma
deaths.
Nodular nevi, however, are far
more likely to change than normal moles. The JAMA
report cites one study in which 78% of patients with
nodular melanoma noted some kind of a change in the
appearance of their lesion. Looking for change also
helped identify other types of melanoma. For instance,
in one cited study, of 169 pigmented lesions, dermatologists
recorded that spots that changed were at least four
times more likely to be melanoma than those that stayed
the same.
These new guidelines come at a
good time. Melanoma is the fastest-growing cancer killer
among Canadian men, with a death rate up by 41% since
1988. In women, the death rate has risen by 23% over
the same period. This year, about 4,000 Canadians will
be diagnosed with the disease, and about 850 will likely
die from it. But just maybe the 'E' in the ABCDE criteria
will help save a few of those lives.
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