Characteristcs of Fast-Growing Melanomas Identified

microscopic image of melanoma

Potentially fatal skin cancers called melanomas are more likely to grow fast
when they’re thicker, symmetrical, elevated, have regular borders or produce
symptoms, a new Australian study found.

“Rapidly growing melanomas can potentially
kill in a matter of weeks,” said lead researcher Dr. Wendy Liu, of the Peter
MacCallum Cancer Center, in East Melbourne.

“They can occur in anyone, not necessarily
those with large numbers of moles and freckles. In fact, they more often occur
in those without large numbers of moles and freckles and elderly men. They are
more often red, rather than brown and black, symmetrical, elevated and
symptomatic,” Liu added.

In the study, Liu’s team investigated the
growth rate of melanoma in 404 patients with invasive melanoma. Patients had
their skin examined, and data about the moles were collected. In addition,
patients were interviewed as soon as possible after
diagnosis.

Patients and their families were asked to
recall when they first noticed a spot on their skin from which the melanoma
later developed, and when they noticed the mole had changed or become
suspicious.

The researchers collected data on
demographics, skin cancer risk factors, the characteristics of the tumor and who
first detected the cancer — the patient, a family member or friend, or a
physician.

Using this information and the thickness of
the tumor when it was removed, Liu’s group was able to estimate its rate of
growth.

The researchers found that about one-third
of all the melanomas grew less than 0.1 millimeters per month, another one-third
grew between 0.1 millimeter and 0.49 millimeters per month, and one-third grew
0.5 millimeters or more per month.

Rapid tumor growth was associated with
tumor thickness, ulceration (formation of a break or sore on the skin),
amelanosis (lack of pigment in the tumor), regular borders, elevation and
symptoms.

Moreover, faster-growing melanomas were
more often found in people 70 and older, in men, and in those with fewer moles
and freckles, the researchers reported.

Factors not associated with the rate of
growth were the number of atypical moles or age spots or liver spots; a history
of sun damage or blistering sunburns; skin type; eye color; family or personal
history of melanoma; and current or childhood sun
exposure.

“Rapidly growing melanomas no longer fit
the classical description of melanomas,” Liu said. “We need to promote the
awareness of this less common but more aggressive form of melanomas among the
health professionals and the general public.”

But Liu cautioned that “any rapidly growing
skin lesion, regardless of its morphology and perceived risk factors for
melanoma, deserves prompt medical assessment.”

The study findings are published in the
December issue of the Archives of Dermatology.

One expert noted that most cancers have
rapidly growing forms.

“This is not a surprising finding,” said
Dr. Vijay Trisal, an assistant professor of surgical oncology at the City of
Hope Cancer Center, in Duarte, Calif. “You can extrapolate these findings to any
tumors in the body.”

Tumors that are fast-growing are more
aggressive, and can divide faster and invade vessels and organs more quickly,
Trisal said.

Trisal added, however, that asking patients
about the growth of their melanoma is not an accurate basis for estimating the
speed of the cancer’s growth. “It is very subjective,” he said. “It also depends
on where the lesion is. If it’s on the back, it might not be noticed for a long
time.”

“Tumors that grow fast are particularly
worrisome, especially if you have no chemotherapy for them,” Trisal said. “For
melanoma, we have no chemotherapy, and the faster they grow, the worse they are,
because that means that the tumor has the ability to get into the blood vessels
and lymph nodes faster.”

People should get medical attention as soon
as they notice a melanoma, Trisal said.

“You can’t just sit there and
watch a melanoma grow and say, ‘Fine, it hasn’t grown in two months, so it is
not that aggressive,’ because you want to get on top of it sooner,” Trisal
added.

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