Melanoma: (A) ITNRODUCTION: Melanoma is a type of skin cancer which forms from melanocytes (pigment-containing cells in the skin). Melanoma is the most serious type of skin cancer. Often the first sign of melanoma is a change in the size, shape, color, or feel of a mole. Most melanomas have a black or black-blue area. Melanoma may also appear as a new mole. It may be black, abnormal, or ugly looking. Thinking of ABCDE can help you remember what to watch for: 1)Asymmetry - the shape of one half does not match the other 2)Border - the edges are ragged, blurred or irregular 3)Color - the color is uneven and may include shades of black, brown and tan 4)Diameter - there is a change in size, usually an increase 5)Evolving - the mole has changed over the past few weeks or months Surgery is the first treatment of all stages of melanoma. Other treatments include chemotherapy and radiation, biologic, and targeted therapies. Biologic therapy boosts your bodys own ability to fight cancer. Targeted therapy uses substances that attack cancer cells without harming normal cells. Melanocytes Melanocytes are cells that produce a pigment called melanin. Melanin is responsible for the natural colour of our skin. It also protects skin from the harmful effects of the sun. When our skin is exposed to sunlight, our melanocytes increase the amount of melanin. This is to absorb more potentially harmful ultraviolet (UV) rays. This makes the skin darker and gives it a suntanned appearance. A suntan is a sign that the skin is trying to protect itself. If you have naturally dark (brown or black) skin, you have the same number of melanocytes as people with white skin, but they make more melanin. This means you have more natural protection from UV rays. Moles (sometimes called naevi) are a group or cluster of melanocytes that are close together. Most people with white skin have about 10–50 moles on their skin. Some people can have as many as 100. (B) TYPES of MELANOMA: a)Superficial spreading melanoma: This is the most common type. In women, the most common place for it to start is on the legs. In men, it’s on the chest and the back. The melanoma cells usually grow slowly at first and spread out across the surface of the skin. b)Nodular melanoma : This is the second most common type. It can grow more quickly than other melanomas and is usually found on the chest, back, head or neck. c)Lentigo maligna melanoma: This type of melanoma is usually found in older people in areas of skin that have had a lot of sun exposure over many years. It’s often found on the face and neck. It develops from a slow-growing precancerous condition called a lentigo maligna or Hutchison’s freckle, which looks like a stain on the skin. d)Acral melanoma: This is the rarest type and is usually found on the palms of the hands, soles of the feet, or under fingernails or toenails. It’s more common in people with black or brown skin and isn’t thought to be related to sun exposure. Advanced melanoma Back : Melanoma is advanced when the cancerous cells have spread from the original melanoma to other parts of the body. When the cancer cells from a tumour spread to a different part of the body, they grow into new a cancer (known as a secondary cancer or metastasis). If melanoma spreads, it’s most likely to spread to one or more of the following parts of the body: #areas of skin distant from the original melanoma #lymph nodes (sometimes called glands) distant from the original melanoma #the lungs #the liver #the bones #the brain. C)Signs and symptoms: a)Asymmetry b)Borders (irregular) c)Color (variegated) d)Diameter (greater than 6 mm (0.24 in), about the size of a pencil eraser) e)Evolving over time Metastatic melanoma may cause nonspecific paraneoplastic symptoms, including loss of appetite, nausea, vomiting and fatigue. Metastasis of early melanoma is possible, but relatively rare: less than a fifth of melanomas diagnosed early become metastatic. Brain metastases are particularly common in patients with metastatic melanoma. It can also spread to the liver, bones, abdomen or distant lymph nodes (D)DIAGNOSIS: a)Blood tests: b)Chest x-ray c)CT (computerised tomography) scan d)MRI (magnetic resonance imaging) scan e)Ultrasound f)Bone scan g)PET (positron emission tomography) scan i)Sentinel lymph node biopsy: You may be offered a test called a sentinel lymph node biopsy (SLNB). This may be done, even if the lymph nodes aren’t swollen. It’s done at the same time as your wide local excision. You can find out more about wide local excision surgery in our section on treatment with surgery. The sentinel nodes are the first ones that lymph fluid drains to from your melanoma. If the melanoma has spread to nearby nodes the sentinel nodes are the ones that are most likely to be affected. A SLNB can tell your doctors more about the stage of your melanoma. Your specialist will talk to you about whether a SLNB is suitable for you. There are still some questions about the helpfulness of SLNBs, so they may leave the decision about whether you have one up to you. 1)Having a sentinel lymph node biopsy: Before your wide local excision, a doctor will inject a tiny amount of a mildly radioactive liquid around the area of your melanoma (where you had your excision biopsy). You will then have a scan to see which lymph nodes the liquid travels to first. These are the sentinel nodes. Then, during the wide local excision, the surgeon injects a blue dye into the same area as the radioactive liquid. The dye stains the sentinel lymph nodes blue. This helps the surgeon find them and remove them. They are sent to a laboratory and examined under a microscope to see if they contain melanoma cells. If the sentinel nodes don’t contain cancer cells, it’s unlikely that other lymph nodes are affected so you won’t need to have surgery to remove them. If they do contain cancer cells, you’ll have further surgery to remove all the lymph nodes near to your melanoma. Your hospital team will discuss with you the benefits and disadvantages of having all the lymph nodes removed. (E)Prevention: 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, use of sunscreens with a sun protection factor (SPF) rating of 50 or higher on exposed areas were recommended; as older sunscreens 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 rejected 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. See Sunscreen controversy for further references and discussions. Using artificial light for tanning was once believed to help prevent skin cancers, but it can actually lead to an increased incidence of melanomas. Even though tanning beds emit mostly UVA, which causes tanning, it by itself might be enough to induce melanomas. A good rule of thumb for decreasing ultraviolet light exposure is to avoid the sun between the hours of 9 a.m. and 3 p.m. or avoid the sun when ones shadow is shorter than ones height. These are rough rules, however, and can vary depending on locality and individual skin cancer risk. Almost all melanomas start with altering the color and appearance of normal-looking skin. This area may be a dark spot or an abnormal new mole. Other melanomas form from a mole or freckle that is already present in the skin. It can be difficult to distinguish between a melanoma and a normal mole. When looking for danger signs in pigmented lesions of the skin, a few simple rules are often used. (F)Treatment: Confirmation of the clinical diagnosis is done with a skin biopsy. This is usually followed up with a wider excision of the scar or tumor. Depending on the stage, a sentinel lymph node biopsy is done, as well, although controversy exists around trial evidence for this procedure. Treatment of advanced malignant melanoma is performed from a multidisciplinary approach. 1)Surgery: a)Before your surgery: Before surgery, the specialist will examine your lymph nodes. This is because the most common place for melanoma cells to spread is to the lymph nodes closest to the melanoma. Your specialist will check whether they look or feel swollen. If the melanoma is on your leg, they’ll examine the lymph nodes behind your knee and in your groin. If it’s on your chest, back or abdomen, they’ll check the lymph nodes in your groin, armpits, above the collarbones and in the neck. If any of these lymph nodes are swollen, or your specialist thinks there is a possibility your melanoma may have spread to them, they will suggest you have tests to check your lymph nodes. Some people may be offered a test to check their lymph nodes even if they aren’t swollen. This test is done at the same time as the surgery and is known as a sentinel lymph node biopsy. Stage 1 melanomas rarely spread to the lymph nodes, so you won’t usually need tests to check them. b)Wide local excision: During a wide local excision, the surgeon removes an amount of normal-looking tissue from all around the area where the melanoma was, including underneath it. This is known as a margin. It’s done to make sure that no melanoma cells have been left behind. The amount of skin that’s removed will depend on how far the melanoma has grown into the deeper layers of the skin. Your specialist will let you know how much skin will be removed. You’ll usually have the wide local excision under a local anaesthetic in the day surgery unit. It may sometimes be done under a general anaesthetic. The wound can usually be stitched together. Your specialist nurse will talk to you about how to look after the wound area. It will look red and sore at first, but this will gradually get better. Your stitches will be removed 5–14 days later, depending on where the melanoma was. You’ll be left with a scar, which is usually small and becomes less noticeable with time. Occasionally, the wound may be too big to stitch together. In this case, you may need to have a skin graft or a skin flap to mend the wound. c)Skin flaps: A skin flap is a slightly thicker layer of skin than a graft. It’s taken from an area very close to where the melanoma was. The flap is cut away but left partially connected so it still has a blood supply. It’s moved over the wound and stitched in place. If you have a skin flap, you may need to stay in hospital for up to four days. Skin flap surgery is very specialised. It’s usually done by a plastic surgeon. You may have to travel to a different hospital to have it. If you need a skin flap, your doctor will be able to tell you more about it. Depending on your surgery, you may have some scars. We have more information about coping with a change in appearance on our life after melanoma page. 2)Adjuvant treatment: High-risk melanomas may require adjuvant treatment, although attitudes to this vary in different countries. In the United States, most patients in otherwise good health will begin up to a year of high-dose interferon treatment, which has severe side effects, but may improve the patients prognosis slightly.British Association of Dermatologist guidelines on melanoma state that interferon is not recommended as a standard adjuvant treatment for melanoma. A 2011 meta-analysis showed that interferon could lengthen the time before a melanoma comes back but increased survival by only 3% at 5 years. The unpleasant side effects also greatly decrease quality of life. In Europe, interferon is usually not used outside the scope of clinical trials.[60][61] Metastatic melanomas can be detected by X-rays, CT scans, MRIs, PET and PET/CTs, ultrasound, LDH testing and photoacoustic detection. 3)Chemotherapy and immunotherapy: Various chemotherapy agents are used, including dacarbazine (also termed DTIC), immunotherapy (with interleukin-2 (IL-2) or interferon (IFN)), as well as local perfusion, are used by different centers. The overall success in metastatic melanoma is quite limited. IL-2 (Proleukin) is the first new therapy approved for the treatment of metastatic melanoma in 20 years. Studies have demonstrated that IL-2 offers the possibility of a complete and long-lasting remission in this disease, although only in a small percentage of patients. As of 2005 A number of new agents and novel approaches are under evaluation and show promise. As of 2009 Clinical trial participation should be considered the standard of care for metastatic melanoma. 4)Radiation therapy: Radiation therapy is often used after surgical resection for patients with locally or regionally advanced melanoma or for patients with unresectable distant metastases. It may reduce the rate of local recurrence but does not prolong survival. Radioimmunotherapy of metastatic melanoma is currently under investigation. Radiotherapy has a role in the palliation of metastatic melanoma. (F)Prognosis: Features that affect prognosis are tumor thickness in millimeters (Breslows depth), depth related to skin structures (Clark level), type of melanoma, presence of ulceration, presence of lymphatic/perineural invasion, presence of tumor-infiltrating lymphocytes (if present, prognosis is better), location of lesion, presence of satellite lesions, and presence of regional or distant metastasis. Certain types of melanoma have worse prognoses but this is explained by their thickness. Interestingly, less invasive melanomas even with lymph node metastases carry a better prognosis than deep melanomas without regional metastasis at time of staging. Local recurrences tend to behave similarly to a primary unless they are at the site of a wide local excision (as opposed to a staged excision or punch/shave excision) since these recurrences tend to indicate lymphatic invasion.
Posted on: Tue, 09 Sep 2014 15:47:46 +0000
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