Skin Cancer
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Skin cancer is a disease in which malignant (cancer) cells form in the
tissues of the skin.
The skin is the body’s largest organ. It protects
against heat, sunlight, injury, and infection. Skin also helps control body
temperature and stores water, fat, and vitamin D. The skin has several layers,
but the two main layers are the epidermis (upper or outer layer) and the dermis
(lower or inner layer). Skin cancer begins in the epidermis, which is made
up of 3 kinds of cells:
- Squamous cells: Thin, flat cells that form the top layer of the epidermis.
- Basal cells: Round cells under the squamous cells.
- Melanocytes: Found in the lower part of the epidermis, these cells make
melanin, the pigment that gives skin its natural color. When skin is exposed
to the sun, melanocytes make more pigment, causing the skin to tan, or darken.
Skin cancer can occur anywhere on the body, but
it is most common in skin that has been exposed to sunlight, such as the face,
neck, hands, and arms. There are several types of cancer that start in the
skin. The most common types are basal cell carcinoma and squamous cell carcinoma,
which are nonmelanoma skin cancers. Actinic keratosis is a skin condition that
sometimes develops into squamous cell carcinoma.
This summary refers to the treatment of nonmelanoma
skin cancer and actinic keratosis. Nonmelanoma skin cancers rarely spread to
other parts of the body. Melanoma, the rarest form of skin cancer, is more
likely to invade nearby tissues and spread to other parts of the body. Refer
to the following PDQ summaries for information on melanoma and other kinds
of skin cancer:
Skin color and exposure to sunlight can affect the risk of developing
nonmelanoma skin cancer and actinic keratosis.
- Being exposed to a lot of natural or artificial sunlight.
- Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history
of freckling).
- Having scars or burns on the skin.
- Being exposed to arsenic.
- Having chronic skin inflammation or skin ulcers.
- Being treated with radiation.
- Taking immunosuppressive drugs (for example, after an organ transplant).
- Having actinic keratosis.
- Being exposed to a lot of sunlight.
- Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history
of freckling).
Nonmelanoma skin cancer and actinic keratosis often appear as a change
in the skin.
Not all changes in the skin are a sign of nonmelanoma
skin cancer or actinic keratosis, but a doctor should be consulted if changes
in the skin are seen.
- A sore that does not heal.
- Areas of the skin that are:
- Small, raised, smooth, shiny, and waxy.
- Small, raised, and red or reddish-brown.
- Flat, rough, red or brown, and scaly.
- Scaly, bleeding, or crusty.
- Similar to a scar and firm.
- A rough, red, pink, or brown, raised, scaly patch on the skin.
- Cracking or peeling of the lower lip that is not helped by lip balm or petroleum
jelly.
Tests or procedures that examine the skin are used to detect (find) and
diagnose nonmelanoma skin cancer and actinic keratosis.
- Skin examination: A doctor or nurse checks the skin for bumps or spots
that look abnormal in color, size, shape, or texture.
- Biopsy: All or part of the abnormal-looking growth is cut from the skin
and viewed under a microscope to see if cancer cells are present. There
are 3 main types of skin biopsies:
- Shave biopsy: A sterile razor blade is used to “shave-off” the abnormal-looking
growth.
- Punch biopsy: A special instrument called a punch or a trephine is
used to remove a circle of tissue from the abnormal-looking growth.
- Excisional biopsy: A scalpel is used to remove the entire growth.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) depends mostly
on the stage of the cancer and the type of treatment used to remove the cancer.
- The stage of the cancer (whether it has spread deeper into the skin
or to other places in the body).
- The type of cancer.
- The size and location of the tumor.
- The patient’s general health.
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After nonmelanoma skin cancer has been diagnosed, tests are done to find
out if cancer cells have spread within the skin or to other parts of the body.
The process used to find out if cancer has spread
within the skin or to other parts of the body is called staging. The information
gathered from the staging process determines the stage of the disease. It is
important to know the stage in order to plan treatment. A biopsy is often the
only test needed to determine the stage of nonmelanoma skin cancer. Lymph nodes
may be examined in cases of squamous cell carcinoma to see if cancer has spread
to them.
The following stages are used for nonmelanoma skin cancer:
In stage 0, cancer is found only in the epidermis
(topmost layer of the skin), in the layer of cells in which the cancer began.
Stage 0 cancer is also called carcinoma in situ.
In stage I, the tumor is 2 centimeters or smaller.
Stage II
In stage II, the tumor is larger than 2 centimeters.
In stage III, cancer has spread below the skin to
cartilage, muscle, or bone and/or to nearby lymph nodes, but not to other parts
of the body.
In stage IV, cancer has spread to other places in
the body.
Treatment choices are based on the type of nonmelanoma skin cancer or
precancerous skin condition diagnosed:
Basal cell carcinoma is the most common type of
skin cancer. It usually occurs on areas of the skin that have been in the sun,
most often on the nose. Often this cancer appears as a small raised bump that
has a smooth, pearly appearance. Another type looks like a scar and is flat
and firm to the touch. Basal cell carcinoma may spread to tissues around the
cancer, but it usually does not spread to other parts of the body.
Squamous cell carcinoma occurs on areas of the skin
that have been in the sun, such as the ears, lower lip, and the back of the
hands. Squamous cell carcinoma may also appear on areas of the skin that have
been burned or exposed to chemicals or radiation. Often this cancer appears
as a firm red bump. Sometimes the tumor may feel scaly or bleed or develop
a crust. Squamous cell tumors may spread to nearby lymph nodes.
Actinic keratosis is a skin condition that is not
cancer, but sometimes changes into squamous cell carcinoma. It usually occurs
in areas that have been exposed to the sun, such as the face, the back of the
hands, and the lower lip. It appears as rough, red, pink, or brown, raised,
scaly patches on the skin, or cracking or peeling of the lower lip that is
not helped by lip balm or petroleum jelly.
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There are different types of treatment for patients with nonmelanoma skin
cancer and actinic keratosis.
Different types of treatment are available for patients
with nonmelanoma skin cancer and actinic keratosis. Some treatments are standard
(the currently used treatment), and some are being tested in clinical trials.
Before starting treatment, patients may want to think about taking part in
a clinical trial. A treatment clinical trial is a research study meant to help
improve current treatments or obtain information on new treatments for patients
with cancer. When clinical trials show that a new treatment is better than
the standard treatment, the new treatment may become the standard treatment.
One or more of the following surgical procedures
may be used to treat nonmelanoma skin cancer or actinic keratosis:
- Mohs micrographic surgery: The tumor is cut from the skin in thin layers.
During surgery, the edges of the tumor and each layer of tumor removed are
viewed through a microscope to check for cancer cells. Layers continue to
be removed until no more cancer cells are seen. This type of surgery removes
as little normal tissue as possible and is often used to remove skin cancer
on the face.
- Simple excision: The tumor is cut from the skin along with some of the
normal skin around it.
- Shave excision: The abnormal area is shaved off the surface of the skin
with a small blade.
- Electrodesiccation and curettage: The tumor is cut from the skin with
a curette (a sharp, spoon-shaped tool). A needle-shaped electrode is then
used to treat the area with an electric current that stops the bleeding
and destroys cancer cells that remain around the edge of the wound. The
process may be repeated one to three times during the surgery to remove
all of the cancer.
- Cryosurgery: A treatment that uses an instrument to freeze and destroy
abnormal tissue, such as carcinoma in situ. This type of treatment is also
called cryotherapy.
- Laser surgery: A surgical procedure that uses a laser beam (a narrow beam
of intense light) as a knife to make bloodless cuts in tissue or to remove
a surface lesion such as a tumor.
- Dermabrasion: Removal of the top layer of skin using a rotating wheel
or small particles to rub away skin cells.
Radiation therapy is a cancer treatment that uses
high-energy x-rays or other types of radiation to kill cancer cells. There
are two types of radiation therapy. External radiation therapy uses a machine
outside the body to send radiation toward the cancer. Internal radiation therapy
uses a radioactive substance sealed in needles, seeds, wires, or catheters
that are placed directly into or near the cancer. The way the radiation therapy
is given depends on the type and stage of the cancer being treated.
Chemotherapy is a cancer treatment that uses drugs
to stop the growth of cancer cells, either by killing the cells or by stopping
the cells from dividing. When chemotherapy is taken by mouth or injected into
a vein or muscle, the drugs enter the bloodstream and can reach cancer cells
throughout the body (systemic chemotherapy). When chemotherapy is placed directly
into the spinal column, an organ, or a body cavity such as the abdomen, the
drugs mainly affect cancer cells in those areas (regional chemotherapy). Chemotherapy
for nonmelanoma skin cancer and actinic keratosis is usually topical (applied
to the skin in a cream or lotion). The way the chemotherapy is given depends
on the condition being treated.
Retinoids (drugs related to vitamin A) are sometimes
used to treat or prevent nonmelanoma skin cancer. The retinoids may be taken
by mouth or applied to the skin. The use of retinoids is being studied in clinical
trials for treatment and prevention of actinic keratosis.
Photodynamic therapy (PDT) is a cancer treatment
that uses a drug and a certain type of laser light to kill cancer cells. A
drug that is not active until it is exposed to light is injected into a vein.
The drug collects more in cancer cells than in normal cells. Fiberoptic tubes
are then used to deliver the laser light to the cancer cells, where the drug
becomes active and kills the cells. Photodynamic therapy causes little damage
to healthy tissue. It is used mainly to treat tumors on or just under the skin
or in the lining of internal organs, such as the lungs and the esophagus.
Other types of treatment are being tested in clinical trials. These include
the following:
Biologic therapy is a treatment that uses the patient’s
immune system to fight cancer. Substances made by the body or made in a laboratory
are used to boost, direct, or restore the body’s natural defenses against disease.
This type of cancer treatment is also called biotherapy or immunotherapy.
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Treatment of basal cell carcinoma may include the
following:
- Mohs micrographic surgery.
- Simple excision.
- Electrodesiccation and curettage.
- Cryosurgery.
- Radiation therapy.
- Laser surgery.
- Topical chemotherapy with fluorouracil.
- Photodynamic therapy.
- A clinical trial of systemic retinoids as chemoprevention.
- A clinical trial of biologic therapy.
Follow-up skin exams are important for people
with basal cell carcinoma because they are likely to have a new or recurrent
tumor within 5 years of the first one. After treatment, the patient should
have skin exams every 6 months for 5 years and once a year after that.
Treatment of squamous cell carcinoma may include
the following:
- Mohs micrographic surgery.
- Simple excision.
- Electrodesiccation and curettage.
- Cryosurgery.
- Radiation therapy.
- Topical chemotherapy with fluorouracil.
- Laser surgery.
- A clinical trial of biologic therapy.
- A clinical trial of biologic therapy and retinoids.
Follow-up skin exams are important for people
with squamous cell carcinoma. Because squamous cell carcinoma can spread, patients
should have skin exams every 3 months for several years after treatment and
then every 6 months.
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Actinic keratosis is not cancer but is treated
because it may develop into cancer. Treatment of actinic keratosis may include
the following:
- Topical chemotherapy.
- Cryosurgery.
- Electrodesiccation and curettage.
- Dermabrasion.
- Shave excision.
- Laser surgery.
- A clinical trial of topical chemotherapy with retinoic acid (a drug related to
vitamin A).
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Merkel cell carcinoma, also called neuroendocrine
cancer of the skin, is a rare type of disease in which malignant (cancer) cells
are found on or just beneath the skin and in hair follicles. Merkel cell carcinoma
usually appears as firm, painless, shiny lumps of skin. These lumps or tumors
can be red, pink, or blue in color and vary in size from less than a quarter
of an inch to more than two inches. Merkel cell carcinoma is usually found
on the sun-exposed areas of the head, neck, arms, and legs. This type of cancer
occurs mostly in whites between 60 and 80 years of age, but it can occur in
people of other races and ages as well.
Merkel cell carcinoma grows rapidly and often metastasizes
(spreads) to other parts of the body. Even relatively small tumors are capable
of metastasizing. When the disease spreads, it tends to spread to the regional
(nearby) lymph nodes and may also spread to the liver, bone, lungs, and brain.
Lymph nodes are small, bean-shaped structures that are found throughout the
body. They produce and store infection-fighting cells.
Treatment of Merkel cell carcinoma depends on the
stage of the disease, and the patient’s age and overall condition.
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After Merkel cell carcinoma has been diagnosed (found),
more tests will be done to find out if cancer cells have spread from the place
the cancer started to other parts of the body. The process used to find out
whether the cancer has spread to other parts of the body is called staging.
It is important to know the stage of the disease to plan the best treatment.
The following stages are used for Merkel cell carcinoma:
The primary tumor has not spread to lymph nodes
or other parts of the body. Lymph nodes are small, bean-shaped structures that
are found throughout the body. They produce and store infection-fighting cells.
The cancer has spread to nearby lymph nodes, but
has not spread to other parts of the body.
The cancer has spread beyond nearby lymph nodes
and to other parts of the body.
Recurrent disease means that the cancer has recurred
(come back) after it has been treated. It may come back in the same part of
the body or in another part of the body.
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- Surgery (taking out the cancer).
- Radiation therapy (using high-dose x-rays or other high-energy rays to kill cancer
cells).
- Chemotherapy (using drugs to kill cancer cells).
- Wide surgical excision takes out the cancer and some of the skin
around the tumor.
- Cryosurgery freezes the tumor and then removes it.
- Micrographic surgery is a tissue-sparing technique that removes only the tumor.
Radiation therapy uses high-energy x-rays to kill
cancer cells and shrink tumors. Radiation may come from a machine outside the
body (external radiation therapy) or from putting materials that produce radiation
(radioisotopes) through thin plastic tubes in the area where the cancer cells
are found (internal radiation therapy).
Chemotherapy uses drugs to kill cancer cells. Chemotherapy
may be taken by pill, or it may be put into the body by a needle in a vein
or muscle. Chemotherapy is called a systemic treatment because the drugs enter
the bloodstream, travel through the body, and can kill cancer cells throughout
the body.
If a doctor removes all the cancer that can be seen
at the time of the operation, a patient may be given chemotherapy after surgery
to kill any cancer cells that are left. Chemotherapy given after an operation
to a person who has no cancer cells that can be found is called adjuvant chemotherapy.
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Treatment may be one of the following:
- Surgery alone.
- Surgery followed by radiation therapy to the tumor site and regional lymph nodes.
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Treatment may be one of the following:
- Surgery alone.
- Surgery followed by radiation therapy to the tumor site and regional lymph nodes.
- Surgery with or without radiation therapy followed by adjuvant chemotherapy.
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Treatment will probably be chemotherapy.
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- Surgery alone.
- Surgery followed by radiation therapy to the tumor site and regional lymph nodes.
- Surgery with or without radiation therapy followed by adjuvant chemotherapy.
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Acne
