The sun is the life-giver on our planet.
It provides the light and the warmth
that we need to survive. However, it
also gives off two types of radiation that
penetrate the atmosphere, the clouds,
and even the layers of our skin. That
radiation is in the form of ultraviolet A
and B (UVA and UVB) rays. These nonvisible forms of light interact with the
DNA of our skin cells, causing damage
to the genes that control how often a
cell divides and multiplies.
When these cells are irrevocably
damaged, the cell loses the ability to
control itself and it repeatedly divides
while ravaging nutrients and space from
the nearby normal cells. If the damaged
cell also starts losing its anchors to the
skin, it can start migrating to other areas
of the body in the form of metastasis.
Depending on the type of skin cancer,
this can rapidly be fatal because the
cancer kills off the normal cells in other
organs and stops their proper function.
More than 3. 7 million skin cancers
were diagnosed in 2008 and the
incidence is increasing drastically. There
are many different types of skin cancer
that I will not delve into in this article
for the sake of brevity, but all of these
cancers are different based on the type
of cell from which the cancer is derived.
The three most common types of
skin cancer are: 1) basal cell carcinoma
(BCC), 2) squamous cell carcinoma
(SCC), and 3) melanoma. BCCs are
derived from cells in the hair follicles.
SCCs are derived from the squamous
cells. These are the cells that you see
with your eyes and feel with your
fingers when you rub your skin. Finally,
melanomas are derived from the
melanocytes which are the cells that give
your skin its pigment or color.
The damage done by the sun however,
doesn’t always lead directly to cancer.
Sometimes there can be an early form
of damage that we term precancerous
lesions or medically termed as actinic
keratosis (actinic means sun or light, and
keratosis refers to a scaly spot on the
These lesions sometimes are almost
better felt than seen, and they present
as rough “sandpaperish” spots on
the skin (Figure 1). They also can be
noticeable as thick, red, scaly spots on
the skin (Figure 2). These early types
of precancers can be readily treated by
your physician without surgery.
There are various methods to
remove these and reduce the chance of
progression to cancer. Such modalities
as freezing the lesions with liquid
nitrogen, application of chemotherapy
creams, and treatment with phototoxic
chemicals are the most common
methods used and can usually be done
with minimal downtime.
Failure to treat actinic keratosis
increases the risk that these lesions will
progress to SCC. Roughly 5% to 10%
of all actinic keratosis left untreated will
Figure 2: A close-up view of an aggressive
precancerous lesion termed a proliferative
actinic keratosis. This spot required
multiple treatment modalities to prevent it
from developing into cancer.
Figure 1: A 50-year-old male with actinic keratosis on
his forehead. These precancerous spots are barely
visible to the patient or the physician.
Figure 3: A fast-growing SCC. This cancer
reached this size within two weeks of the
patient noticing it.
48 Model Aviation SEP TEMBER 2012 www.ModelAviation.com