Melanoma is a malignant tumor of melanocytes which are found predominantly in skin but also in the bowel and the eye (see uveal melanoma). It is one of the rarer types of skin cancer but causes the majority of skin cancer related deaths. Malignant melanoma is a serious type of skin cancer. It is due to uncontrolled growth of pigment cells, called melanocytes. Despite many years of intensive laboratory and clinical research, the sole effective cure is surgical resection of the primary tumor before it achieves a Breslow thickness greater than 1 mm.
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Around 160,000 new cases of melanoma are diagnosed worldwide each year, and it is more frequent in males and caucasians. It is more common in caucasian populations living in sunny climates than other groups. According to a WHO Report about 48,000 melanoma related deaths occur worldwide per year.
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Malignant melanoma accounts for 75 percent of all deaths associated with skin cancer.
The treatment includes surgical removal of the tumor; adjuvant treatment; chemo- and immunotherapy, or radiation therapy.
Generally, an individual’s risk for developing melanoma depends on two groups of factors: intrinsic and environmental.”Intrinsic” factors are generally an individual’s family history and inherited genotype, while the most relevant environmental factor is sun exposure.
Epidemiologic studies suggest that exposure to ultraviolet radiation (UVA and UVB) is one of the major contributors to the development of melanoma. UV radiation causes damage to the DNA of cells, typically thymine dimerization, which when unrepaired can create mutations in the cell’s genes. When the cell divides, these mutations are propagated to new generations of cells. If the mutations occur in protooncogenes or tumor suppressor genes, the rate of mitosis in the mutation-bearing cells can become uncontrolled, leading to the formation of a tumor. Data from patients suggest that aberrant levels of Activating Transcription Factor in the nucleus of melanoma cells are associated with increased metastatic activity of melanoma cells; studies from mice on skin cancer tend to confirm a role for Activating Transcription Factor-2 in cancer progression. Occasional extreme sun exposure (resulting in “sunburn“) is causally related to melanoma. Melanoma is most common on the back in men and on legs in women (areas of intermittent sun exposure). The risk appears to be strongly influenced by socio-economic conditions rather than indoor versus outdoor occupations; it is more common in professional and administrative workers than unskilled workers. Other factors are mutations in or total loss of tumor suppressor genes. Use of sunbeds (with deeply penetrating UVA rays) has been linked to the development of skin cancers, including melanoma.
Possible significant elements in determining risk include the intensity and duration of sun exposure, the age at which sun exposure occurs, and the degree of skin pigmentation. Exposure during childhood is a more important risk factor than exposure in adulthood. This is seen in migration studies in Australia where people tend to retain the risk profile of their country of birth if they migrate to Australia as an adult. Individuals with blistering or peeling sunburns (especially in the first twenty years of life) have a significantly greater risk for melanoma. This does not mean that sunburn is the cause of melanoma. Instead it is merely statistically correlated. The cause is the exaggerated UV-exposure. It has been shown that sunscreen – while preventing the sunburn – does not protect from melanoma. Many researchers say that sunscreen can even increase the melanoma risk.
Fair and red-headed people, persons with multiple atypical nevi or dysplastic nevi and persons born with giant congenital melanocytic nevi are at increased risk.
A family history of melanoma greatly increases a person’s risk because mutations in CDKN2A, CDK4 and several other genes have been found in melanoma-prone families. Patients with a history of one melanoma are at increased risk of developing a second primary tumour.
The incidence of melanoma has increased in the recent years, but it is not clear to what extent changes in behavior, in the environment, or in early detection are involved.
To understand how sunscreen can reduce sunburn and at the same time cause melanoma it is necessary to distinguish between direct DNA damage and indirect DNA damage. Genetic analysis has shown that 92% of all melanoma are caused by the indirect DNA damage. Although some people believe that dark-skinned people such as African Americans cannot get sunburns, they are in fact susceptible, and should use sunscreen accordingly. The recommended amount of sunscreen for adults is 1 oz, which is enough to fill a shot glass.
Familial melanoma is genetically heterogeneous, and loci for familial melanoma have been identified on the chromosome arms 1p, 9p and 12q. Multiple genetic events have been related to the pathogenesis of melanoma. The multiple tumor suppressor 1 (CDKN2A/MTS1) gene encodes p16INK4a – a low-molecular weight protein inhibitor of cyclin-dependent protein kinases (CDKs) – which has been localised to the p21 region of human chromosome 9. Today, melanomas are diagnosed only after they become visible on the skin. In the future, however, physicians will hopefully be able detect melanomas based on a patient’s genotype, not just his or her phenotype. Recent genetic advances promise to help doctors to identify people with high-risk genotypes and to determine which of a person’s lesions have the greatest chance of becoming cancerous. A number of rare mutations, which often run in families, are known to greatly increase one’s susceptibility to melanoma. One class of mutations affects the gene CDKN2A. An alternative reading frame mutation in this gene leads to the destabilization of p53, a transcription factor involved in apoptosis and in fifty percent of human cancers. Another mutation in the same gene results in a non-functional inhibitor of CDK4, a [cyclin-dependent kinase] that promotes cell division. Mutations that cause the skin condition Xeroderma Pigmentosum (XP) also seriously predispose one to melanoma. Scattered throughout the genome, these mutations reduce a cell’s ability to repair DNA. Both CDKN2A and XP mutations are highly penetrant. Other mutations confer lower risk but are more prevalent in the population. People with mutations in the MC1R gene, for example, are two to four times more likely to develop melanoma than those with two wild-type copies of the gene. MC1R mutations are very common; in fact, all people with red hair have a mutated copy of the gene. Two-gene models of melanoma risk have already been created, and in the future, researchers hope to create genome-scale models that will allow them to predict a patient’s risk of developing melanoma based on his or her genotype. In addition to identifying high-risk patients, researchers also want to identify high-risk lesions within a given patient. Many new technologies, such as optical coherence tomography (OCT), are being developed to accomplish this. OCT allows pathologists to view 3-D reconstructions of the skin and offers more resolution than past techniques could provide. In vivo confocal microscopy and fluorescently tagged antibodies are also proving to be valuable diagnostic tools.
Symptoms and signs:
To detect melanomas (and increase survival rates), it is recommended to learn what they look like (see “ABCD” mnemonic below), to be aware of moles and check for changes (shape, size, color, itching or bleeding) and to show any suspicious moles to a doctor with an interest and skills in skin malignancy.
A popular method for remembering the signs and symptoms of melanoma is the mnemonic “ABCD”:
*Asymmetrical skin lesion.
*Border of the lesion is irregular.
*Color: melanomas usually have multiple colors.
*Diameter: moles greater than 6 mm are more likely to be melanomas than smaller moles.
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ABCD rule illustration. On the left side from top to bottom: melanomas showing (A) Asymmetry, (B) a border that is uneven, ragged, or notched, (C) coloring of different shades of brown, black, or tan and (D) diameter that had changed in size. The normal moles on the right side do not have abnormal characteristics (no asymmetry, even border, even color, no change in diametry).
A weakness in this system is the D. Many melanomas present themselves as lesions smaller than 6 mm in diameter; and likely all melanomas were melanomas on day 1 of growth, which is merely a dot. An astute physician will examine all abnormal moles, including ones less than 6 mm in diameter. Unfortunately for the average person, many seborrheic keratosis breaks most if not all of the ABCD rules, and can not be distinguished from a melanoma without a trained eye or dermatoscopy.
Some will advocate the system “ABCDE”, with E for evolution. Certainly moles which change and evolve will be a concern. Some will refer to E as elevation. But most melanomas detected today are in the very early stage, or in-situ stage. Elevation should absolutely not be a criterion to wait for, as it will be past in-situ and into the invasive stage.
A recent and novel method of melanoma detection is the “Ugly Duckling Sign” It is simple, easy to teach, and highly effective in detecting melanoma. Simply, correlation of common characteristics of a person’s skin lesion is made. Lesions which greatly deviate from the common characteristics are labeled as an “Ugly Duckling”, and further professional exam is required. The “Little Red Riding Hood” sign, suggests that individuals with fair skin and light colored hair might have difficult to diagnose melanomas. Extra care and caution should be rendered when examining such individuals as they might have multiple melanomas and severely dysplastic nevi. A dermatoscope must be used to detect “ugly ducklings”, as many melanomas in these individuals resemble non-melanomas or are considered to be “wolves in sheep clothing”. These fair skinned individuals often have lightly pigmented or amelanotic melanomas which will not present easy to observe color changes and variation in colors. The borders of these amelanotic melanomas are often indistinct, making visual identification without a dermatoscope (dermatoscopy) very difficult.
People with a personal or family history of skin cancer or of dysplastic nevus syndrome (multiple atypical moles) should see a dermatologist at least once a year to be sure they are not developing melanoma.
Moles that are irregular in color or shape are suspicious of a malignant or a premalignant melanoma. Following a visual examination and a dermatoscopic exam, used routinely by one in 4 dermatologists in the United States, or an examination using other in vivo diagnostic tools, such as a confocal microscope, the doctor may biopsy the suspicious mole. If it is malignant, the mole and an area around it needs excision.
The diagnosis of melanoma requires experience, as early stages may look identical to harmless moles or not have any color at all. A skin biopsy performed under local anesthesia is often required to assist in making or confirming the diagnosis and in defining the severity of the melanoma. Amelanotic melanomas and melanomas arising in fair skinned individuals (see the “Little Red Riding Hood” sign) are very difficult to detect as they fail to show many of the characteristics in the ABCD rule, and breaks the “Ugly Duckling” sign. These melanomas are often light brown, or pink in color – and very hard to distinguish from acne scarring, insect bites, dermatofibromas, or lentigines. There is no blood test for detecting melanomas.
Excisional skin biopsy is the management of choice; this is where the suspect lesion is totally removed with an adequate (but minimal, usually 1 or 2 mm) ellipse of surrounding skin and tissue. The preferred surgical margin for the initial biopsy should be narrow (1 mm) in order to prevent the disruption of the local lymphatic drainage. The biopsy will include the epidermal, dermal, and subcutaneous layers of the skin, enabling the histopathologist to determine the depth of penetration of the melanoma by microscopic examination. This is described by Clark’s level (involvement of skin structures) and Breslow’s depth (measured in millimeters). However, for large lesions such as suspected lentigo maligna, or for lesions in surgically difficult areas (face, toes, fingers, eyelids), a small punch biopsy (1.5 to 2 mm) in multiple representative areas will give adequate information and will not disrupt the final staging or depth determination. In no circumstances should the initial biopsy include the final surgical margin (0.5 cm, 1.0cm, or 2 cm), as a misdiagnosis can result in excessive scarring and morbidity from the procedure. Large initial excision will disrupt the local lymphatic drainage and can affect further lymphangiogram directed lymphnode dissection. A small punch biopsy can be utilized at anytime where for logistical and personal reasons a patient will refused more invasive excisional biopsy. Small punch biopsies are minimally invasive and heal quickly, usually without noticeable scarring.
Malignant melanoma in skin biopsy with H&E stain. This case may represent superficial spreading melanoma.
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Lactate dehydrogenase (LDH) tests are often used to screen for metastases, although many patients with metastases (even end-stage) have a normal LDH; extraordinarily high LDH often indicates metastatic spread of the disease to the liver. It is common for patients diagnosed with melanoma to have chest X-rays and an LDH test, and in some cases CT, MRI, PET and/or PET/CT scans. Although controversial, sentinel lymph node biopsies and examination of the lymph nodes are also performed in patients to assess spread to the lymph nodes.
Sometimes the skin lesion may bleed, itch, or ulcerate, although this is a very late sign. A slow-healing lesion should be watched closely, as that may be a sign of melanoma. Be aware also that in circumstances that are still poorly understood, melanomas may “regress” or spontaneously become smaller or invisible – however the malignancy is still present. Amelanotic (colorless or flesh-colored) melanomas do not have pigment and may not even be visible. Lentigo maligna, a superficial melanoma confined to the topmost layers of the skin (found primarily in older patients) is often described as a “stain” on the skin. Some patients with metastatic melanoma do not have an obvious detectable primary tumor.
The doctor can describe treatment choices and discuss the results expected with each treatment option. The doctor and patient can work together to develop a treatment plan that fits the patient’s needs. Treatment for melanoma depends on the extent of the disease, the patient’s age and general health, and other factors.
People with melanoma are often treated by a team of specialists. The team may include a dermatologist, surgeon, medical oncologist, radiation oncologist, and plastic surgeon.
Getting a second opinion
Before starting treatment, the patient might want a second opinion about the diagnosis and the treatment plan. Some insurance companies require a second opinion; others may cover a second opinion if the patient or doctor requests it.
There are a number of ways to find a doctor for a second opinion:
The patient’s doctor may refer the patient to one or more specialists. At cancer centers, several specialists often work together as a team.
The Cancer Information Service, at 1-800-4-CANCER, can tell callers about nearby treatment centers.
A local or state medical society, a nearby hospital, or a medical school can usually provide the names of specialists.
The American Board of Medical Specialties (ABMS) has a list of doctors who have met certain education and training requirements and have passed specialty examinations. The Official ABMS Directory of Board Certified Medical Specialists lists doctors’ names along with their specialty and their educational background. The directory is available in most public libraries. Also, ABMS offers this information on the Internet at(You may Click on to see “Who’s Certified.”)
Preparing for treatment
People with melanoma often want to take an active part in making decisions about their medical care. They want to learn all they can about their disease and their treatment choices. However, shock and stress after a diagnosis of a melanoma can make it hard to think of everything to ask the doctor. It often helps to make a list of questions before an appointment. To help remember what the doctor says, patients may take notes or ask whether they may use a tape recorder. Some also want to have a family member or friend with them when they talk to the doctor—to take part in the discussion, to take notes, or just to listen.
These are some questions a person may want to ask the doctor before treatment begins:
*What is my diagnosis?
*What is the stage of my disease?
*What are my treatment choices? Which do you recommend for me? Why?
*What are the benefits of each kind of treatment?
*What are the risks and possible side effects of each treatment?
*How will I feel after surgery?
*If I have pain, how will it be controlled?
*Will I need more treatment after surgery?
*Will there be a scar? Will I need a skin graft or plastic surgery?
*What is the treatment likely to cost?
*Will treatment affect my normal activities? If so, for how long?
*How often will I need checkups?
*Would a clinical trial (research study) be appropriate for me? Can you help me find one?
People do not need to ask all of their questions or understand all of the answers at one time. They will have other chances to ask the doctor to explain things that are not clear and to ask for more information.
Methods of treatment:-
People with melanoma may have surgery, chemotherapy, biological therapy, or radiation therapy. Patients may have a combination of treatments.
At any stage of disease, people with melanoma may have treatment to control pain and other symptoms of the cancer, to relieve the side effects of therapy, and to ease emotional and practical problems. This kind of treatment is called symptom management, supportive care, or palliative care.
The doctor is the best person to describe the treatment choices and discuss the expected results.
A patient may want to talk to the doctor about taking part in a clinical trial, a research study of new treatment methods. The section on “The Promise of Cancer Research” has more information about clinical trials.
Surgery is the usual treatment for melanoma. The surgeon removes the tumor and some normal tissue around it. This procedure reduces the chance that cancer cells will be left in the area. The width and depth of surrounding skin that needs to be removed depends on the thickness of the melanoma and how deeply it has invaded the skin:
*The doctor may be able to completely remove a very thin melanoma during the biopsy. Further surgery may not be necessary.
*If the melanoma was not completely removed during the biopsy, the doctor takes out the remaining tumor. In most cases, additional surgery is performed to remove normal-looking tissue around the tumor (called the margin) to make sure all melanoma cells are removed. This is often necessary, even for thin melanomas. If the melanoma is thick, the doctor may need to remove a larger margin of tissue.
If a large area of tissue is removed, the surgeon may do a skin graft. For this procedure, the doctor uses skin from another part of the body to replace the skin that was removed.
Lymph nodes near the tumor may be removed because cancer can spread through the lymphatic system. If the pathologist finds cancer cells in the lymph nodes, it may mean that the disease has also spread to other parts of the body. Two procedures are used to remove the lymph nodes:
*Sentinel lymph node biopsy—The sentinel lymph node biopsy is done after the biopsy of the melanoma but before the wider excision of the tumor. A radioactive substance is injected near the melanoma. The surgeon follows the movement of the substance on a computer screen. The first lymph node(s) to take up the substance is called the sentinel lymph node(s). (The imaging study is called lymphoscintigraphy. The procedure to identify the sentinel node(s) is called sentinel lymph node mapping.) The surgeon removes the sentinel node(s) to check for cancer cells.
If a sentinel node contains cancer cells, the surgeon removes the rest of the lymph nodes in the area. However, if a sentinel node does not contain cancer cells, no additional lymph nodes are removed.
*Lymph node dissection—The surgeon removes all the lymph nodes in the area of the melanoma.
Therapy may be given after surgery to kill cancer cells that remain in the body. This treatment is called adjuvant therapy. The patient may receive biological therapy.
Surgery is generally not effective in controlling melanoma that has spread to other parts of the body. In such cases, doctors may use other methods of treatment, such as chemotherapy, biological therapy, radiation therapy, or a combination of these methods.
Chemotherapy, the use of drugs to kill cancer cells, is sometimes used to treat melanoma. The drugs are usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Usually a patient has chemotherapy as an outpatient (at the hospital, at the doctor’s office, or at home). However, depending on which drugs are given and the patient’s general health, a short hospital stay may be needed.
People with melanoma may receive chemotherapy in one of the following ways:
*By mouth or injection—Either way, the drugs enter the bloodstream and travel throughout the body.
*Isolated limb perfusion (also called isolated arterial perfusion)—For melanoma on an arm or leg, chemotherapy drugs are put directly into the bloodstream of that limb. The flow of blood to and from the limb is stopped for a while. This allows most of the drug to reach the tumor directly. Most of the chemotherapy remains in that limb.
The drugs may be heated before injection. This type of chemotherapy is called hyperthermic perfusion.
Biological therapy (also called immunotherapy) is a form of treatment that uses the body’s immune system, either directly or indirectly, to fight cancer or to reduce side effects caused by some cancer treatments. Biological therapy for melanoma uses substances called cytokines. The body normally produces cytokines in small amounts in response to infections and other diseases. Using modern laboratory techniques, scientists can produce cytokines in large amounts. In some cases, biological therapy given after surgery can help prevent melanoma from recurring. For patients with metastatic melanoma or a high risk of recurrence, interferon alpha and interleukin-2 (also called IL-2 or aldesleukin) may be recommended after surgery.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. A large machine directs radiation at the body. The patient usually has treatment at a hospital or clinic, five days a week for several weeks. Radiation therapy may be used to help control melanoma that has spread to the brain, bones, and other parts of the body. It may shrink the tumor and relieve symptoms.
Treatment choices by stage:
The following are brief descriptions of the treatments most often used for each stage. (Other treatments may sometimes be appropriate.)
People with Stage 0 melanoma may have minor surgery to remove the tumor and some of the surrounding tissue.
People with Stage I melanoma may have surgery to remove the tumor. The surgeon may also remove as much as 2 centimeters (3/4 inch) of tissue around the tumor. To cover the wound, the patient may have skin grafting.
Stage II or stage III
People with Stage II or Stage III melanoma may have surgery to remove the tumor. The surgeon may also remove as much as 3 centimeters (1 1/4 inches) of nearby tissue. Skin grafting may be done to cover the wound. Sometimes the surgeon removes nearby lymph nodes.
People with Stage IV melanoma often receive palliative care. The goal of palliative care is to help the patient feel better—physically and emotionally. This type of treatment is intended to control pain and other symptoms and to relieve the side effects of therapy (such as nausea), rather than to extend life.
The patient may have one of the following:
Surgery to remove lymph nodes that contain cancer cells or to remove tumors that have spread to other areas of the body
Radiation therapy, biological therapy, or chemotherapy to relieve symptoms
People with advanced melanoma can find helpful information in the National Cancer Institute booklet Pain Control: A Guide for People with Cancer and Their Families.
Treatment for recurrent melanoma depends on where the cancer came back, which treatments the patient has already received, and other factors. As with Stage IV melanoma, treatment usually cannot cure melanoma that recurs. Palliative care is often an important part of the treatment plan. Many patients have palliative care to ease their symptoms while they are getting anticancer treatments to slow the progress of the disease. Some receive only palliative care to improve their quality of life by easing pain, nausea, and other symptoms.
The patient may have one of the following:
*Surgery to remove the tumor
*Radiation therapy, biological therapy, or chemotherapy to relieve symptoms
Heated chemotherapy drugs injected directly into the tumor
Because treatment may damage healthy cells and tissues, unwanted side effects sometimes occur. These side effects depend on many factors, including the location of the tumor and the type and extent of the treatment. Side effects may not be the same for each person, and they may even change from one treatment session to the next. Before treatment starts, the health care team will explain possible side effects and suggest ways to help the patient manage them.
The NCI provides helpful booklets about cancer treatments and coping with side effects, such as Radiation Therapy and You, Chemotherapy and You, and Eating Hints for Cancer Patients. See the sections “National Cancer Institute Information Resources” and “National Cancer Institute Booklets” for other sources of information about side effects.
The side effects of surgery depend mainly on the size and location of the tumor and the extent of the operation. Although patients may have some pain during the first few days after surgery, this pain can be controlled with medicine. People should feel free to discuss pain relief with the doctor or nurse. It is also common for patients to feel tired or weak for a while. The length of time it takes to recover from an operation varies for each patient.
Scarring may also be a concern for some patients. To avoid causing large scars, doctors remove as little tissue as they can (while still protecting against recurrence). In general, the scar from surgery to remove an early stage melanoma is a small line (often 1 to 2 inches long), and it fades with time. How noticeable the scar is depends on where the melanoma was, how well the person heals, and whether the person develops raised scars called keloids. When a tumor is large and thick, the doctor must remove more surrounding skin and other tissue (including muscle). Although skin grafts reduce scarring caused by the removal of large growths, these scars will still be quite noticeable.
Surgery to remove the lymph nodes from the underarm or groin may damage the lymphatic system and slow the flow of lymphatic fluid in the arm or leg. Lymphatic fluid may build up in a limb and cause swelling (lymphedema). The doctor or nurse can suggest exercises or other ways to reduce swelling if it becomes a problem. Also, it is harder for the body to fight infection in a limb after nearby lymph nodes have been removed, so the patient will need to protect the arm or leg from cuts, scratches, bruises, insect bites, or burns that may lead to infection. If an infection does develop, the patient should see the doctor right away.
The side effects of chemotherapy depend mainly on the specific drugs and the dose. In general, anticancer drugs affect cells that divide rapidly, especially:
*Blood cells: These cells fight infection, help the blood to clot, and carry oxygen to all parts of the body. When drugs affect blood cells, patients are more likely to get infections, may bruise or bleed easily, and may feel very weak and tired.
*Cells in hair roots: Chemotherapy can lead to hair loss. The hair grows back, but the new hair may be somewhat different in color and texture.
*Cells that line the digestive tract: Chemotherapy can cause poor appetite, nausea and vomiting, diarrhea, or mouth and lip sores. Many of these side effects can be controlled with drugs.
The side effects of biological therapy vary with the type of treatment. These treatments may cause flu-like symptoms, such as chills, fever, muscle aches, weakness, loss of appetite, nausea, vomiting, and diarrhea. Patients may also get a skin rash. These problems can be severe, but they go away after treatment stops.
The side effects of radiation therapy depend on the amount of radiation given and the area being treated. Side effects that may occur in the treated area include red or dry skin and hair loss. Radiation therapy also may cause fatigue. Although the side effects of radiation therapy can be unpleasant, the doctor can usually treat or control them. It also helps to know that, in most cases, side effects are not permanent.
People with melanoma may not feel like eating, especially if they are uncomfortable or tired. Also, the side effects of treatment, such as poor appetite, nausea, or vomiting, can be a problem. Foods may taste different. Nevertheless, patients should try to eat well during cancer therapy. They need enough calories to maintain a good weight and protein to keep up strength. Good nutrition often helps people with cancer feel better and have more energy.
The doctor, dietitian, or other health care provider can suggest ways to maintain a healthy diet. Patients and their families may want to read the National Cancer Institute booklet Eating Hints for Cancer Patients, which contains many useful ideas and recipes. The “National Cancer Institute Booklets” section tells how to get this publication.
For more knowledge You may click to see:
*What about followup care after treatment for melanoma?
*Are there support groups for people with melanoma?
*What steps are involved in performing a skin self-exam?
*Where can patients get more information about melanoma?
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Minimizing exposure to sources of ultraviolet radiation (the sun and sunbeds), following sun protection measures and wearing sun protective clothing (long-sleeved shirts, long trousers, and broad-brimmed hats) can offer protection. In the past it was recommended to use sunscreens with an SPF rating of 30 or higher on exposed areas as older sunscreen more effectively blocked UVA with higher SPF. Currently, newer sunscreen ingredients (avobenzone, zinc, and titanium) effectively block both UVA and UVB even at lower SPFs. However, there are questions about the ability of sunscreen to prevent melanoma.This controversy is well discussed in numerous review articles, and is refuted by most dermatologists. This correlation might be due to the confounding variable that individuals who used sunscreen to prevent burn, might have a higher lifetime exposure to either UVA or UVB. Please see Sunscreen controversy for further references and discussions. Tanning, once believed to help prevent skin cancers, actually can lead to increase incidence of melanomas Even though tanning beds emits mostly UVA, which causes tanning, it by itself might be enough to induce melanomas.
Rough rules of thumb to decreasing ultraviolet light exposure include avoiding the sun between the hours of 9 a.m. and 3 p.m. or avoiding the sun when your shadow is shorter than your height. These are rough rules of thumbs, and varies depending on your locality and your skin cancer risk.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose