What
is Skin Cancer?
Cancer
develops when DNA becomes damaged and the body
cannot repair the damage. These damaged cells
begin to grow and divide uncontrollably. When
this occurs in the skin, skin cancer develops.
As the damaged cells multiply, they form a tumor.
Since skin cancer generally develops in the epidermis,
the outermost layers of skin, a tumor is usually
clearly visible. This makes most skin cancers
detectable in the early stages.
Types
of Skin Cancer
Three types of skin cancer account for nearly
100% of all diagnosed cases. Each of these three
cancers begins in a different type of cell within
the skin, and each cancer is named for the type
of cell in which it begins. Skin cancers are divided
into one of two classes - nonmelanoma skin cancers
and melanoma. Melanoma
is the most dangerous form of skin cancer.
The
different types of skin cancer are:
Basal
cell carcinoma (BCC):
The
most common cancer in humans, BCC develops in
more than 1 million people every year in the
United States alone. About 80% of all skin cancers
are BCC, a cancer that develops in the basal
cells - skin cells located in the lowest layer
of the epidermis. BCC can take several forms.
It can appear as a shiny translucent or pearly
nodule, a sore that continuously heals and then
re-opens, a pink slightly elevated growth, reddish
irritated patches of skin, or a waxy scar. Most
BCCs appear on skin with a history of exposure
to the sun, such as the face, ears, scalp, and
upper trunk. These tumors tend to grow slowly
and can take years to reach ½ inch in
size. While these tumors very rarely metastasize
(cancer spreads to other parts of the body),
dermatologists encourage early diagnosis and
treatment to prevent extensive damage to surrounding
tissue.
Squamous
cell carcinoma (SCC):
About
16% of diagnosed skin cancers are SCC. This
cancer begins in the squamous cells, which are
found in the upper layer of the epidermis. About
200,000 cases are diagnosed ever year. SCC tends
to develop in fair-skinned middle-aged and elderly
people who have had long-term sun exposure.
It most often appears as a crusted or scaly
area of skin with a red inflamed base that resembles
a growing tumor, non-healing ulcer, or crusted-over
patch of skin. While most commonly found on
sun-exposed areas of the body, it can develop
anywhere, including the inside of the mouth
and the genitalia. SCC may arise from actinic
keratoses, which are dry, scaly lesions that
may be skin-colored, reddish-brown or yellowish-black.
SCC requires early treatment to prevent metastasis
(spreading).
Melanoma:
Accounting
for about 4% of all diagnosed skin cancers,
melanoma begins in the melanocytes, the cells
within the epidermis that give skin its color.
Melanoma is the most dangerous form of skin
cancer because it can rapidly spread to the
lymph system and internal organs and lead to
other complications. In the United States alone,
approximately one person dies from melanoma
every hour. Older white males have the highest
mortality rate. Dermatologists believe this
is due to the fact that they are less likely
to heed the early warning signs. With early
detection and proper treatment, the cure rate
for melanoma is about 95%. Once its spreads,
the prognosis is poor. Melanoma most often develops
in a pre-existing mole or looks like a new mole,
which is why it is important for people to know
what their moles look like and be able to detect
changes to existing moles and spot new moles.
Other
nonmelanoma skin cancers:
All
other skin cancers combined account for less
than 1% of diagnosed cases. These are classified
as nonmelanoma skin cancers and include Merkel
cell carcinoma, dermatofibromasarcoma protuberans,
Pagets disease and cutaneous T-cell lymphoma.
Causes
Sun
exposure is the leading cause of skin cancer.
According to the American Cancer Society, Many
of the more than 1 million skin cancers diagnosed
each year could be prevented with protection from
the suns rays. Scientists now know
that exposure to the suns ultraviolet (UV)
rays damages DNA in the skin. The body can usually
repair this damage before gene mutations occur
and cancer develops. When a persons body
cannot repair the damaged DNA, which can occur
with cumulative sun exposure, cancer develops.
In
some cases, skin cancer is an inherited condition.
Between 5% and 10% of melanomas develop in people
with a family history of melanoma.
Who
Gets Skin Cancer?
Skin
cancer develops in people of all colors, from
the palest to the darkest. However, skin cancer
is most likely to occur in those who have fair
skin, light-colored eyes, blonde or red hair,
a tendency to burn or freckle when exposed to
the sun, and a history of sun exposure. Anyone
with a family history of skin cancer also has
an increased risk of developing skin cancer. In
dark-skinned individuals, melanoma most often
develops on non-sun-exposed areas, such as the
foot, underneath nails, and on the mucous membranes
of the mouth, nasal passages, or genitals. Those
with fair skin also can have melanoma develop
in these areas.
Skin
Cancer Rates Rising
While
Americans now recognize that overexposure to the
sun is unhealthy, the fact remains that most do
not protect their skin from the suns harmful
rays. As a result, skin cancer is common in the
United States. More than 1 million nonmelanoma
skin cancers are diagnosed each year, and approximately
one person dies from melanoma every hour.
If
current trends continue, 1 in 5 Americans will
develop skin cancer during their lifetime. Melanoma
continues to rise at an alarming rate. In 1930,
1 in 5,000 Americans was likely to develop melanoma
during their lifetime. By 2004, this ratio jumped
to 1 in 65. Today, melanoma is the second most
common cancer in women aged 20 to 29.
Prevention
and Early Detection Key
Sun protection can significantly decrease a persons
risk of developing skin cancer. Sun protection
practices include staying out of the sun between
10 a.m. and 4 p.m. when the rays are strongest,
applying a broad-spectrum (offers UVA and UVB
protection) sunscreen with a Sun Protection Factor
(SPF) of 15 or higher year-round to all exposed
skin, and wearing a protective clothing, such
as a wide-brimmed hat and sunglasses when outdoors.
Since
skin cancer is so prevalent today, dermatologists
also recommend that everyone learn how to recognize
the signs of skin cancer, use this knowledge to
perform regular examinations of their skin, and
see a dermatologist annually (more frequently
if at high risk) for an exam. Skin cancer is highly
curable with early detection and proper treatment.
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