Melanoma
By Babar Rao, MD and Komal Pandya, RPh
What is Melanoma?
Melanoma is a type of skin cancer. Other common skin cancers include basal
cell carcinoma and squamous cell carcinoma. Melanoma is the deadliest of the
three skin cancers and occurs when there is an uncontrolled growth of melanocytes.
Melanocytes are cells that produce a pigment called melanin, which determines
the color of our skin, hair and eyes. Melanin also provides protection against
the damaging effects of sunrays. Sometimes, these melanocytes can grow in a
controlled and organized manner and can form noncancerous growths called moles.
Moles are very common. Most adults have between 10 and 40 benign moles on their
bodies. However, when the melanocytes grow out of control, they become malignant
melanoma.
Melanoma occurs most commonly in the skin,
but can also occur in other areas where melanocytes are found, such as the eyes,
nails, and the digestive tract.
How Common is Melanoma?
An estimated 54,000 individuals develop melanoma and almost
7,600 die of it each year in the United States. The majority of these cases
occur in the 15 to 50-year-old age group. The incidence of melanoma has doubled
over the past three decades and is rising more rapidly than any other cancer.
In the United States, melanoma is the most common cancer
in women ages 25 to 29, and the second most common cancer (after breast cancer)
in women between the ages of 30 and 34 years. Overall, males have higher incident
rates of melanoma than females. However, in these age groups, melanoma is more
frequent in women than in men.
Who is at the Highest Risk of Developing Melanoma?
The exact cause of melanoma is not known. However, there
are certain risk factors that make a person more likely than others to develop
melanoma. The risk factors for melanoma are as follows:
- Ultraviolet (UV) radiation: Experts believe that much of the worldwide
increase in melanoma is related to an increased amount of sun exposure. Skin
cancers other than melanoma, such as squamous cell and basal cell carcinomas
are associated with the total amount of sun exposure one has had over their
entire life. Melanoma, on the other hand, is more often linked to intense
exposure to sunlight of skin that has not been exposed to sun for a while.
The use of tanning salons puts a person at higher risk of developing nonmelanoma
skin cancers, however, its link to melanoma is not known.
- Fair skin: Melanoma occurs more frequently in people who have light
skin especially those who have red or blond hair and blue or green eyes. Anyone
who burns or freckles easily in the sun without tanning is more susceptible
to developing melanoma.
- Severe, blistering sunburns: Anyone who has had at least one severe,
blistering sunburn as a child or an adolescent is at increased risk of melanoma.
Sunburns in adulthood are also a risk factor for melanoma.
- Personal history of skin cancer: A person who has had melanoma
or other skin cancers such as basal cell or squamous cell carcinoma in the
past, is at higher risk of developing melanoma.
- Dysplastic nevi: If a person has a mole biopsied and it turns out
to be a "dysplastic nevus," it means that it is an abnormal-looking mole that
is more likely to become cancerous than an ordinary mole. The risk of melanoma
is raised by a factor of 12 if a person has 10 or more of these dysplastic
nevi.
- Many ordinary moles: A person who has greater than 50 common moles
is considered "melanoma prone."
- Family history of melanoma: Sometimes melanoma runs in families.
About 10% of all melanoma cases are the result of an inherited risk. Having
two or more close relatives with a history of melanoma puts a person at an
increased risk for melanoma.
- Weakened immune system: Persons whose immune system is weakened
by certain cancers, or by HIV, are at increased risk of developing melanoma.
NOTE: There is no evidence that oral contraceptives play a role in the development
of melanoma.
What are the "ABCDs" of Melanoma?
Several features are used to help differentiate a benign mole from a melanoma.
The mnemonic used for these characteristics is "the ABCDs:"
A. Asymmetry: Melanoma lesions are usually asymmetric. If
you were to draw a line through the middle of a melanoma lesion it would not
create matching halves. Common moles are symmetrical and round in shape.
B. Border: The edges of melanomas are often irregular,
notched, or blurred. Common moles have nice smooth, clearly-defined borders.
C. Color: Melanomas have various colors in the lesions. Shades
of black, brown, and tan may be present in early lesions of melanoma. Areas
of red, white and blue are seen as melanomas progress. Common moles are uniformly
colored, usually a shade of brown.
D. Diameter: Early melanomas usually increase in size. Melanomas
are usually larger than 1/4 inch (about the size of a pencil eraser). If
a lesion on your body possesses any of the above characteristics, then it
is considered "suspicious" and needs to be evaluated by your dermatologist.
How do Dermatologists Diagnose Melanomas?
Every diagnosis begins with a thorough examination of the skin by a physician.
The "ABCD" characteristics of melanoma are used to differentiate it from a benign
mole. If the physician sees anything suspicious, a biopsy is be performed.
Biopsy is a procedure where a sample of your skin is taken and sent to the lab
for analysis. It is the most accurate diagnostic test. However, biopsies can
be painful and have risks associated with them, therefore an astute doctor will
first try to rule out any noncancerous lesions through physical examination,
thus minimizing the need for unnecessary biopsies.
What are Some New Ways of Diagnosing Melanoma?
For years dermatologists have relied upon their naked eyes
for evaluation of colored lesions but the ability of human eyes to detect subtle
differences is limited. New instruments are being developed that enhance the
evaluator's vision of pigmented lesions.
- Dermoscope: Some doctors now employ dermoscopy (also known
as dermatoscopy or epiluminescence microscopy), which uses a hand-held device
with a lens and a light source similar to an ophthalmoscope used to examine
the eyes. Oil is applied to the skin lesion to allow better penetration of
light, and the glass head of the scope is then pressed firmly against the
skin. The physician then looks at the lesion through the lens. This allows
approximately fourteen times magnification of the lesion and thus better visualization
and differentiation of certain features of benign and malignant tumors.
- Digital Image Capture: A digital camera is attached to the
head of the dermoscope for taking photographs of the suspicious lesion. These
images can then be downloaded onto a computer, which can later be emailed,
printed or digitally stored. In this way, a brief patient record containing
these dermoscopic pictures can be created.Images of a particular lesion on
a patient, which are taken on different dates, can be compared directly on
the screen side-by-side. This facilitates a reliable comparison of any changes
within the mole.
In addition, in high-melanoma-risk patients, such as those with dysplastic
nevi, a series of images of the whole body can be obtained and stored on a
floppy disk so that the patients can use it at home to monitor alterations
in their moles.
- Computer Assisted Diagnosis: Images of a suspicious lesion
can be analyzed in terms of their color, geometry and texture using various
computer programs. These software programs read these images and give them
a value score. The value score is then compared with a databank of melanoma
images to help determine if the lesion in question is cancerous. This type
of a program is not a substitute for the dermatologist's judgment but rather
is an aid that helps him/her arrive to an accurate diagnosis.
- Ultrasound for Skin: Most people are familiar with ultrasound
being used to visualize a person's internal organs (for example a pregnant
woman gets periodic ultrasounds to visualize her baby). Recently, a European
company introduced an instrument that uses the principles of ultrasound to
specifically help evaluate skin lesions. The basic principle behind this
is that the ultrasound waves that are generated by the machine are absorbed
and then reflected by skin lesions. These reflected waves are transformed
into electric impulses and are displayed on a monitor as an image. Different
types of lesions reflect these ultrasound waves differently. A melanoma will
reflect ultrasound waves differently than a benign mole and thus will create
its own unique image on the monitor.
The use of these instruments makes the detection of malignant
melanoma and other conditions easier and more reliable. Some physicians are
employing these techniques before deciding to perform a biopsy in order to minimize
the number of unnecessary biopsies. These techniques are non-invasive and are
painless and can provide the physician with more information than is obtained
with the naked eye.
What Happens Once Melanoma is Diagnosed?
There are four approaches to treating melanoma skin cancer: surgery, chemotherapy,
radiation therapy and immunotherapy. One or a combination of the above options
may be used to treat melanoma depending on how far the cancer has spread.
How Can Melanoma be Prevented?
Studies have shown that avoiding sunburns, especially in
childhood and adolescence, may reduce the risk of melanoma skin cancer. Sunburns
can be avoided by:
- Avoiding midday sun exposure (from 11am to 3pm), when the sun is most intense
- Wearing sun-protective clothing, such as hats and long sleeve shirts
- Using sunscreens with an SPF of at least 15
Remember: Sunscreen is not a substitute for avoiding
sun exposure.
Examine your skin every three months or so, keeping the "ABCDs" of melanoma
in mind. In women, melanoma occurs most commonly on the lower legs, followed
by arms, chest, and back.
Have your skin examined yearly by a dermatologist if you have any of the previously
mentioned risk factors.
Dermatologist and dermatopathologist, Babar Rao, MD,
is internationally known for his work in melanocytic neoplasms. He currently
serves as the Director of the Melanoma Pigmented Lesion Center and as the Residency
Program Director and Assistant Professor of the Division of Dermatology at the
University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical
School in New Brunswick, New Jersey.
Dr. Rao's research involves non-invasive tools for diagnosing
melanomas and other skin cancers. He has published approximately 35 papers,
has written chapters in a number of textbooks, and is a well-known speaker at
dermatology meetings. Dr. Rao initially trained in dermatology at the Institute
of Dermatology, St. John's/St. Thomas' Hospital in London. He completed a dermatology
residency at New York Presbyterian Hospital-Cornell University Medical College
and obtained advanced training in melanoma at New York University Medical Center
and in dermtopathology at University of Medicine and Dentistry of New Jersey/New
Jersey Medical School. To access Dr. Rao's website, click
here. To contact Dr. Rao, click here.
Komal Pandya, RPh is currently a fourth year medical
student at Robert Wood Johnson Medical School-University of Medicine and Dentistry
of New Jersey. She is planning on specializing in the field of dermatology.
Ms. Pandya is currently involved in researching the protective effects of green
tea against skin cancer. She received her undergraduate degree in pharmacy
at Rutgers University, Ernest Mario School of Pharmacy, where she graduated
as the Salutatorian of her class.
Created: 11/8/2003 - Babar Rao, MD & Komal Pandya, RPh
Reviewed: 11/8/2003 - Donnica Moore, M.D.
