Enamel Hypoplasia

Enamel is the hard, protective outer layer of your teeth. Enamel hypoplasia is a defect of the enamel that only occurs while teeth are still developing. Still, it can affect both baby teeth and permanent teeth. The condition results in thin enamel, which makes your teeth vulnerable to dental decay.

The visual signs of enamel hypoplasia include white spots, pits, and grooves on the outer surface of the teeth.

Tooth enamel is the hardest substance in your body, but it doesn’t contain living cells and can’t repair itself or improve on its own. So, if you or your child has enamel hypoplasia, you’ll need to have a dentist monitor your teeth and act quickly to repair problem areas.

What are the symptoms?

Some of the signs of enamel hypoplasia are obvious, but others are more difficult to detect and may not be noticeable until they cause major dental problems. Having thin tooth enamel can lead to:

• pits, tiny groves, depressions, and fissures
• white spots
• yellowish-brown stains (where the underlying layer of dentin is exposed)
• sensitivity to heat and cold
• lack of tooth contact, irregular wearing of teeth
• susceptibility to acids in food and drink
• retention of harmful bacteria
• increased vulnerability to tooth decay and cavities

What causes it?

Defective enamel development can be the result of an inherited condition called amelogenesis imperfecta, or congenital enamel hypoplasia, which is estimated to affect about 1 in 14,000 people in the United States. This condition can also cause unusually small teeth and a variety of dental problems. Congenital enamel hypoplasia can happen alone or as part of a syndrome affecting other parts of the body.

Other hereditary syndromes that can cause enamel hypoplasia are:

• Usher syndrome
• Seckel syndrome
• Ellis-van Creveld syndrome
• Treacher Collins syndrome
• otodental syndrome
• 22q11 deletion syndrome (velocardiofacial syndrome)
• Heimler syndrome

Enamel hypoplasia can also result from prenatal issues such as:

• maternal vitamin D deficiency
• maternal weight gain
• maternal smoking
• maternal drug use
• lack of prenatal care
• premature birth or low birth weight

Environmental factors and other problems in infancy that can cause enamel hypoplasia include:

• trauma to the teeth
• infection
• calcium deficiency
• deficiencies of vitamins A, C, or D
• jaundice, liver disease
• celiac disease
• cerebral palsy due to maternal or fetal infection

How is it treated?

Early screening and diagnosis are crucial. That’s why children should see a dentist sometime between the appearance of their first tooth and their first birthday.

Treatment depends on the severity of the problem. Goals of treatment are to:

• prevent tooth decay
• maintain a good bite
• preserve tooth structure
• keep teeth looking their best

Some of the smaller defects that aren’t causing decay or sensitivity may not need treatment right away. They still require monitoring, though. Your dentist will probably want to apply topical fluoride to help protect teeth.

In the case of sensitivity, cavities, or tooth structure showing wear, treatment options include:

• Resin-bonded sealant. This can improve tooth sensitivity.
• Resin-based composite fillings. These can be made to closely match tooth color, which makes them ideal for use on front or back teeth. They’re also quite durable.
• Dental amalgam fillings. These are made from a combination of durable metals. Due to the silver color, you may not want them on your front teeth.
• Gold fillings. Like dental amalgam fillings, gold fillings are durable but lack a natural look. They also tend to be the most expensive.
• Crowns. These completely cover the tooth.
• Enamel microabrasion. This is a minimally invasive procedure to improve appearance of the teeth.
• Professional dental whitening.

There are cases in which a permanent tooth is so malformed that it may be best to extract it. If so, you might want to consult with an orthodontist first.

Here are a few other tips for keeping your teeth as healthy as possible:

• Brush at least twice a day using a soft toothbrush.
• If cold sensitivity is a problem, rinse with lukewarm water.
• Keep sugary and acidic foods and drinks to a minimum, and always brush and rinse thoroughly after consuming them.
• See your dentist regularly for check-ups and whenever you suspect a problem.

What are the potential complications?

Without proper treatment, complications can include:

• cavities, crumbling tooth (caries)
• browning of an entire tooth
• need for tooth extractions
• anxiety about the appearance of your smile

Things that contribute to these complications include poor oral hygiene, eating too much sugar, and crowded teeth.

Osteoporosis

Osteoporosis causes bones to become weak and brittle — so brittle that a fall or even mild stresses such as bending over or coughing can cause a fracture. Osteoporosis-related fractures most commonly occur in the hip, wrist or spine.

Bone is living tissue that is constantly being broken down and replaced. Osteoporosis occurs when the creation of new bone doesn't keep up with the loss of old bone.

Osteoporosis affects men and women of all races. But white and Asian women — especially older women who are past menopause — are at highest risk. Medications, healthy diet and weight-bearing exercise can help prevent bone loss or strengthen already weak bones.

Products & Services

• Book: Mayo Clinic Guide to Preventing and Treating Osteoporosis

Symptoms

There typically are no symptoms in the early stages of bone loss. But once your bones have been weakened by osteoporosis, you might have signs and symptoms that include:

• Back pain, caused by a fractured or collapsed vertebra
• Loss of height over time
• A stooped posture
• A bone that breaks much more easily than expected

When to see a doctor

You might want to talk to your doctor about osteoporosis if you went through early menopause or took corticosteroids for several months at a time, or if either of your parents had hip fractures.

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Causes

• 

  Osteoporosis weakens bone

Your bones are in a constant state of renewal — new bone is made and old bone is broken down. When you're young, your body makes new bone faster than it breaks down old bone and your bone mass increases. After the early 20s this process slows, and most people reach their peak bone mass by age 30. As people age, bone mass is lost faster than it's created.

How likely you are to develop osteoporosis depends partly on how much bone mass you attained in your youth. Peak bone mass is somewhat inherited and varies also by ethnic group. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age.

Risk factors

A number of factors can increase the likelihood that you'll develop osteoporosis — including your age, race, lifestyle choices, and medical conditions and treatments.

Unchangeable risks

Some risk factors for osteoporosis are out of your control, including:

• Your sex. Women are much more likely to develop osteoporosis than are men.
• Age. The older you get, the greater your risk of osteoporosis.
• Race. You're at greatest risk of osteoporosis if you're white or of Asian descent.
• Family history. Having a parent or sibling with osteoporosis puts you at greater risk, especially if your mother or father fractured a hip.
• Body frame size. Men and women who have small body frames tend to have a higher risk because they might have less bone mass to draw from as they age.

Hormone levels

Osteoporosis is more common in people who have too much or too little of certain hormones in their bodies. Examples include:

• Sex hormones. Lowered sex hormone levels tend to weaken bone. The reduction of estrogen levels in women at menopause is one of the strongest risk factors for developing osteoporosis.
  Men have a gradual reduction in testosterone levels as they age. Treatments for prostate cancer that reduce testosterone levels in men and treatments for breast cancer that reduce estrogen levels in women are likely to accelerate bone loss.
• Thyroid problems. Too much thyroid hormone can cause bone loss. This can occur if your thyroid is overactive or if you take too much thyroid hormone medication to treat an underactive thyroid.
• Other glands. Osteoporosis has also been associated with overactive parathyroid and adrenal glands.

Dietary factors

Osteoporosis is more likely to occur in people who have:

• Low calcium intake. A lifelong lack of calcium plays a role in the development of osteoporosis. Low calcium intake contributes to diminished bone density, early bone loss and an increased risk of fractures.
• Eating disorders. Severely restricting food intake and being underweight weakens bone in both men and women.
• Gastrointestinal surgery. Surgery to reduce the size of your stomach or to remove part of the intestine limits the amount of surface area available to absorb nutrients, including calcium. These surgeries include those to help you lose weight and for other gastrointestinal disorders.

Steroids and other medications

Long-term use of oral or injected corticosteroid medications, such as prednisone and cortisone, interferes with the bone-rebuilding process. Osteoporosis has also been associated with medications used to combat or prevent:

• Seizures
• Gastric reflux
• Cancer
• Transplant rejection

Medical conditions

The risk of osteoporosis is higher in people who have certain medical problems, including:

• Celiac disease
• Inflammatory bowel disease
• Kidney or liver disease
• Cancer
• Lupus
• Multiple myeloma
• Rheumatoid arthritis

Lifestyle choices

Some bad habits can increase your risk of osteoporosis. Examples include:

• Sedentary lifestyle. People who spend a lot of time sitting have a higher risk of osteoporosis than do those who are more active. Any weight-bearing exercise and activities that promote balance and good posture are beneficial for your bones, but walking, running, jumping, dancing and weightlifting seem particularly helpful.
• Excessive alcohol consumption. Regular consumption of more than two alcoholic drinks a day increases your risk of osteoporosis.
• Tobacco use. The exact role tobacco plays in osteoporosis isn't clear, but it has been shown that tobacco use contributes to weak bones.

Complications

• 

  Compression fractures

Bone fractures, particularly in the spine or hip, are the most serious complications of osteoporosis. Hip fractures often are caused by a fall and can result in disability and even an increased risk of death within the first year after the injury.

In some cases, spinal fractures can occur even if you haven't fallen. The bones that make up your spine (vertebrae) can weaken to the point of crumpling, which can result in back pain, lost height and a hunched forward posture.

Prevention

Good nutrition and regular exercise are essential for keeping your bones healthy throughout your life.

Protein

Protein is one of the building blocks of bone. However, there's conflicting evidence about the impact of protein intake on bone density.

Most people get plenty of protein in their diets, but some do not. Vegetarians and vegans can get enough protein in the diet if they intentionally seek suitable sources, such as soy, nuts, legumes, seeds for vegans and vegetarians, and dairy and eggs for vegetarians.

Older adults might eat less protein for various reasons. If you think you're not getting enough protein, ask your doctor if supplementation is an option.

Body weight

Being underweight increases the chance of bone loss and fractures. Excess weight is now known to increase the risk of fractures in your arm and wrist. As such, maintaining an appropriate body weight is good for bones just as it is for health in general.

Calcium

Men and women between the ages of 18 and 50 need 1,000 milligrams of calcium a day. This daily amount increases to 1,200 milligrams when women turn 50 and men turn 70.

Good sources of calcium include:

• Low-fat dairy products
• Dark green leafy vegetables
• Canned salmon or sardines with bones
• Soy products, such as tofu
• Calcium-fortified cereals and orange juice

If you find it difficult to get enough calcium from your diet, consider taking calcium supplements. However, too much calcium has been linked to kidney stones. Although yet unclear, some experts suggest that too much calcium especially in supplements can increase the risk of heart disease.

The Health and Medicine Division of the National Academies of Sciences, Engineering and Medicine (formerly the Institute of Medicine) recommends that total calcium intake, from supplements and diet combined, should be no more than 2,000 milligrams daily for people older than 50.

Vitamin D

Vitamin D improves your body's ability to absorb calcium and improves bone health in other ways. People can get some of their vitamin D from sunlight, but this might not be a good source if you live in a high latitude, if you're housebound, or if you regularly use sunscreen or avoid the sun because of the risk of skin cancer.

To get enough vitamin D to maintain bone health, it's recommended that adults ages 51 to 70 get 600 international units (IU) and 800 IU a day after age 70 through food or supplements.

People without other sources of vitamin D and especially with limited sun exposure might need a supplement. Most multivitamin products contain between 600 and 800 IU of vitamin D. Up to 4,000 IU of vitamin D a day is safe for most people.

Exercise

Exercise can help you build strong bones and slow bone loss. Exercise will benefit your bones no matter when you start, but you'll gain the most benefits if you start exercising regularly when you're young and continue to exercise throughout your life.

Combine strength training exercises with weight-bearing and balance exercises. Strength training helps strengthen muscles and bones in your arms and upper spine. Weight-bearing exercises — such as walking, jogging, running, stair climbing, skipping rope, skiing and impact-producing sports — affect mainly the bones in your legs, hips and lower spine. Balance exercises such as tai chi can reduce your risk of falling especially as you get older.

Swimming, cycling and exercising on machines such as elliptical trainers can provide a good cardiovascular workout, but they don't improve bone health.

Skin cancers

Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body.^[10] There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma.^[1] The first two, along with a number of less common skin cancers, are known as nonmelanoma skin cancer (NMSC).^[5][11] Basal-cell cancer grows slowly and can damage the tissue around it but is unlikely to spread to distant areas or result in death.^[5] It often appears as a painless raised area of skin that may be shiny with small blood vessels running over it or may present as a raised area with an ulcer.^[1] Squamous-cell skin cancer is more likely to spread.^[5] It usually presents as a hard lump with a scaly top but may also form an ulcer.^[2] Melanomas are the most aggressive. Signs include a mole that has changed in size, shape, color, has irregular edges, has more than one color, is itchy or bleeds.^[3]

More than 90% of cases are caused by exposure to ultraviolet radiation from the Sun.^[4] This exposure increases the risk of all three main types of skin cancer.^[4] Exposure has increased, partly due to a thinner ozone layer.^[5][12] Tanning beds are another common source of ultraviolet radiation.^[4] For melanomas and basal-cell cancers, exposure during childhood is particularly harmful.^[6] For squamous-cell skin cancers, total exposure, irrespective of when it occurs, is more important.^[4] Between 20% and 30% of melanomas develop from moles.^[6] People with lighter skin are at higher risk^[1][13] as are those with poor immune function such as from medications or HIV/AIDS.^[5][14] Diagnosis is by biopsy.^[3]

Decreasing exposure to ultraviolet radiation and the use of sunscreen appear to be effective methods of preventing melanoma and squamous-cell skin cancer.^[6][7] It is not clear if sunscreen affects the risk of basal-cell cancer.^[7] Nonmelanoma skin cancer is usually curable.^[5] Treatment is generally by surgical removal but may, less commonly, involve radiation therapy or topical medications such as fluorouracil.^[1] Treatment of melanoma may involve some combination of surgery, chemotherapy, radiation therapy and targeted therapy.^[3] In those people whose disease has spread to other areas of the body, palliative care may be used to improve quality of life.^[3] Melanoma has one of the higher survival rates among cancers, with over 86% of people in the UK and more than 90% in the United States surviving more than 5 years.^[15][16]

Skin cancer is the most common form of cancer, globally accounting for at least 40% of cancer cases.^[5][17] The most common type is nonmelanoma skin cancer, which occurs in at least 2–3 million people per year.^[6][18] This is a rough estimate, however, as good statistics are not kept.^[1] Of nonmelanoma skin cancers, about 80% are basal-cell cancers and 20% squamous-cell skin cancers.^[11] Basal-cell and squamous-cell skin cancers rarely result in death.^[6] In the United States, they were the cause of less than 0.1% of all cancer deaths.^[1] Globally in 2012, melanoma occurred in 232,000 people and resulted in 55,000 deaths.^[6] White people in Australia, New Zealand and South Africa have the highest rates of melanoma in the world.^[6][19] The three main types of skin cancer have become more common in the last 20 to 40 years, especially in those areas with mostly White people.^[5][6]

Classification[edit]

There are three main types of skin cancer: basal-cell skin cancer (basal-cell carcinoma) (BCC), squamous-cell skin cancer (squamous-cell carcinoma) (SCC) and malignant melanoma.

Cancer	Description	Illustration
Basal-cell carcinoma	Note the pearly translucency to fleshy color, tiny blood vessels on the surface, and sometimes ulceration which can be characteristics. The key term is translucency.
Squamous-cell skin carcinoma	Commonly presents as a red, crusted, or scaly patch or bump. Often a very rapidly growing tumor.
Malignant melanoma	These are commonly asymmetrical in shape and/or pigment distribution, with an irregular border, color variation, and often greater than 6 mm diameter.[20]

Basal-cell carcinomas are most commonly present on sun-exposed areas of the skin, especially the face. They rarely metastasize and rarely cause death. They are easily treated with surgery or radiation. Squamous-cell skin cancers are also common, but much less common than basal-cell cancers. They metastasize more frequently than BCCs. Even then, the metastasis rate is quite low, with the exception of SCC of the lip, ear, and in people who are immunosuppressed. Melanoma are the least frequent of the three common skin cancers. They frequently metastasize, and potentially cause death once they spread.

Less common skin cancers include: dermatofibrosarcoma protuberans, Merkel cell carcinoma, Kaposi's sarcoma, keratoacanthoma, spindle cell tumors, sebaceous carcinomas, microcystic adnexal carcinoma, Paget's disease of the breast, atypical fibroxanthoma, leiomyosarcoma, and angiosarcoma.

BCC and SCC often carry a UV-signature mutation indicating that these cancers are caused by UVB radiation via direct DNA damage. However malignant melanoma is predominantly caused by UVA radiation via indirect DNA damage. The indirect DNA damage is caused by free radicals and reactive oxygen species. Research indicates that the absorption of three sunscreen ingredients into the skin, combined with a 60-minute exposure to UV, leads to an increase of free radicals in the skin, if applied in too little quantity and too infrequently.^[21] However, the researchers add that newer creams often do not contain these specific compounds, and that the combination of other ingredients tends to retain the compounds on the surface of the skin. They also add that frequent re-application reduces the risk of radical formation.

Signs and symptoms[edit]

There are a variety of different skin cancer symptoms. These include changes in the skin that do not heal, ulcering in the skin, discolored skin, and changes in existing moles, such as jagged edges to the mole and enlargement of the mole.

Basal-cell skin cancer[edit]

Basal-cell skin cancer (BCC) usually presents as a raised, smooth, pearly bump on the sun-exposed skin of the head, neck, torso or shoulders. Sometimes small blood vessels (called telangiectasia) can be seen within the tumor. Crusting and bleeding in the center of the tumor frequently develops. It is often mistaken for a sore that does not heal. This form of skin cancer is the least deadly, and with proper treatment can be completely eliminated, often without significant scarring.

Squamous-cell skin cancer[edit]

Squamous-cell skin cancer (SCC) is commonly a red, scaling, thickened patch on sun-exposed skin. Some are firm hard nodules and dome shaped like keratoacanthomas. Ulceration and bleeding may occur. When SCC is not treated, it may develop into a large mass. Squamous-cell is the second most common skin cancer. It is dangerous, but not nearly as dangerous as a melanoma.

Melanoma[edit]

Most melanoma consist of various colours from shades of brown to black. A small number of melanoma are pink, red or fleshy in colour; these are called amelanotic melanoma and tend to be more aggressive. Warning signs of malignant melanoma include change in the size, shape, color or elevation of a mole. Other signs are the appearance of a new mole during adulthood or pain, itching, ulceration, redness around the site, or bleeding at the site. An often-used mnemonic is "ABCDE", where A is for "asymmetrical", B for "borders" (irregular: "Coast of Maine sign"), C for "color" (variegated), D for "diameter" (larger than 6 mm – the size of a pencil eraser) and E for "evolving."^[22][23]

Other[edit]

Merkel cell carcinomas are most often rapidly growing, non-tender red, purple or skin colored bumps that are not painful or itchy. They may be mistaken for a cyst or another type of cancer.^[24]

Causes[edit]

Ultraviolet radiation from sun exposure is the primary environmental cause of skin cancer.^[25][26][27] This can occur in professions such as farming. Other risk factors that play a role include:

• Smoking tobacco^[26]
• HPV infections increase the risk of squamous-cell skin cancer.^[26]
• Some genetic syndromes^[26] including congenital melanocytic nevi syndrome which is characterized by the presence of nevi (birthmarks or moles) of varying size which are either present at birth, or appear within 6 months of birth. Nevi larger than 20 mm (3/4") in size are at higher risk for becoming cancerous.
• Chronic non-healing wounds.^[26] These are called Marjolin's ulcers based on their appearance, and can develop into squamous-cell skin cancer.
• Ionizing radiation such as X-rays, environmental carcinogens, artificial UV radiation (e.g. tanning beds), aging, and light skin color.^[26] It is believed that tanning beds are the cause of hundreds of thousands of basal and squamous-cell skin cancer.^[28] The World Health Organization now places people who use artificial tanning beds in its highest risk category for skin cancer.^[29] Alcohol consumption, specifically excessive drinking increase the risk of sunburns.^[30]
• The use of many immunosuppressive medications increases the risk of skin cancer. Cyclosporin A, a calcineurin inhibitor for example increases the risk approximately 200 times, and azathioprine about 60 times.^[31]

Pathophysiology[edit]

Micrograph of melanoma, fine-needle aspiration (FNA), field stain

A malignant epithelial tumor that primarily originates in the epidermis, in squamous mucosa or in areas of squamous metaplasia is referred to as a squamous-cell carcinoma.^[32]

Macroscopically, the tumor is often elevated, fungating, or may be ulcerated with irregular borders. Microscopically, tumor cells destroy the basement membrane and form sheets or compact masses which invade the subjacent connective tissue (dermis). In well differentiated carcinomas, tumor cells are pleomorphic/atypical, but resembling normal keratinocytes from prickle layer (large, polygonal, with abundant eosinophilic (pink) cytoplasm and central nucleus).^[32]

Their disposal tends to be similar to that of normal epidermis: immature/basal cells at the periphery, becoming more mature to the centre of the tumor masses. Tumor cells transform into keratinized squamous cells and form round nodules with concentric, laminated layers, called "cell nests" or "epithelial/keratinous pearls". The surrounding stroma is reduced and contains inflammatory infiltrate (lymphocytes). Poorly differentiated squamous carcinomas contain more pleomorphic cells and no keratinization.^[32]

A molecular factor involved in the disease process is mutation in gene PTCH1 that plays an important role in the Sonic hedgehog signaling pathway.^[33]

Diagnosis[edit]

Diagnosis is by biopsy and histopathological examination.^[3]

Non-invasive skin cancer detection methods include photography, dermoscopy, sonography, confocal microscopy, Raman spectroscopy, fluorescence spectroscopy, terahertz spectroscopy, optical coherence tomography, the multispectral imaging technique, thermography, electrical bio-impedance, tape stripping and computer-aided analysis.^[34]

Computer-assisted diagnosis devices have been developed that analyze images from a dermatoscope or spectroscopy and can be used by a diagnostician to aid in the detection of skin cancer. CAD systems have been found to be highly sensitive in the detection of melanoma, but have a high false-positive rate. There is not yet enough evidence to recommend CAD as compared to traditional diagnostic methods.^[35]

High-frequency ultrasound (HFUS) is of unclear usefulness in the diagnosis of skin cancer.^[36]

Prevention[edit]

Sunscreen is effective and thus recommended to prevent melanoma^[37] and squamous-cell carcinoma.^[38] There is little evidence that it is effective in preventing basal-cell carcinoma.^[39] Other advice to reduce rates of skin cancer includes avoiding sunburning, wearing protective clothing, sunglasses and hats, and attempting to avoid sun exposure or periods of peak exposure.^[40] The U.S. Preventive Services Task Force recommends that people between 9 and 25 years of age be advised to avoid ultraviolet light.^[41]

The risk of developing skin cancer can be reduced through a number of measures including decreasing indoor tanning and mid day sun exposure, increasing the use of sunscreen,^[42] and avoiding the use of tobacco products.

There is insufficient evidence either for or against screening for skin cancers.^[43] Vitamin supplements and antioxidant supplements have not been found to have an effect in prevention.^[44] Evidence for reducing melanoma risk from dietary measures is tentative, with some supportive epidemiological evidence, but no clinical trials.^[45]

Zinc oxide and titanium oxide are often used in sun screen to provide broad protection from UVA and UVB ranges.^[46]

Eating certain foods may decrease the risk of sunburns but this is much less than the protection provided by sunscreen.^[47]

A meta-analysis of skin cancer prevention in high risk individuals found evidence that topical application of T4N5 liposome lotion reduced the rate of appearance of basal cell carcinomas in people with xeroderma pigmentosum, and that acitretin taken by mouth may have a skin protective benefit in people following kidney transplant.^[48]

Treatment[edit]

Treatment is dependent on the specific type of cancer, location of the cancer, age of the person, and whether the cancer is primary or a recurrence. For a small basal-cell cancer in a young person, the treatment with the best cure rate (Mohs surgery or CCPDMA) might be indicated. In the case of an elderly frail man with multiple complicating medical problems, a difficult to excise basal-cell cancer of the nose might warrant radiation therapy (slightly lower cure rate) or no treatment at all. Topical chemotherapy might be indicated for large superficial basal-cell carcinoma for good cosmetic outcome, whereas it might be inadequate for invasive nodular basal-cell carcinoma or invasive squamous-cell carcinoma.^{[citation needed]} In general, melanoma is poorly responsive to radiation or chemotherapy.

For low-risk disease, radiation therapy (external beam radiotherapy^[49] or brachytherapy), topical chemotherapy (imiquimod or 5-fluorouracil) and cryotherapy (freezing the cancer off) can provide adequate control of the disease; all of them, however, may have lower overall cure rates than certain type of surgery. Other modalities of treatment such as photodynamic therapy, topical chemotherapy, electrodesiccation and curettage can be found in the discussions of basal-cell carcinoma and squamous-cell carcinoma.

Mohs' micrographic surgery (Mohs surgery) is a technique used to remove the cancer with the least amount of surrounding tissue and the edges are checked immediately to see if tumor is found. This provides the opportunity to remove the least amount of tissue and provide the best cosmetically favorable results. This is especially important for areas where excess skin is limited, such as the face. Cure rates are equivalent to wide excision. Special training is required to perform this technique. An alternative method is CCPDMA and can be performed by a pathologist not familiar with Mohs surgery.

In the case of disease that has spread (metastasized), further surgical procedures or chemotherapy may be required.^[50]

Treatments for metastatic melanoma include biologic immunotherapy agents ipilimumab, pembrolizumab, and nivolumab; BRAF inhibitors, such as vemurafenib and dabrafenib; and a MEK inhibitor trametinib.^[51]

Reconstruction[edit]

Currently, surgical excision is the most common form of treatment for skin cancers. The goal of reconstructive surgery is restoration of normal appearance and function. The choice of technique in reconstruction is dictated by the size and location of the defect. Excision and reconstruction of facial skin cancers is generally more challenging due to presence of highly visible and functional anatomic structures in the face.

When skin defects are small in size, most can be repaired with simple repair where skin edges are approximated and closed with sutures. This will result in a linear scar. If the repair is made along a natural skin fold or wrinkle line, the scar will be hardly visible. Larger defects may require repair with a skin graft, local skin flap, pedicled skin flap, or a microvascular free flap. Skin grafts and local skin flaps are by far more common than the other listed choices.

Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster dressing is placed atop the graft for seven to ten days, to immobilize the graft as it heals in place. There are two forms of skin grafting: split thickness and full thickness. In a split thickness skin graft, a shaver is used to shave a layer of skin from the abdomen or thigh. The donor site regenerates skin and heals over a period of two weeks. In a full thickness skin graft, a segment of skin is totally removed and the donor site needs to be sutured closed.^[52]

Split thickness grafts can be used to repair larger defects, but the grafts are inferior in their cosmetic appearance. Full thickness skin grafts are more acceptable cosmetically. However, full thickness grafts can only be used for small or moderate sized defects.

Local skin flaps are a method of closing defects with tissue that closely matches the defect in color and quality. Skin from the periphery of the defect site is mobilized and repositioned to fill the deficit. Various forms of local flaps can be designed to minimize disruption to surrounding tissues and maximize cosmetic outcome of the reconstruction. Pedicled skin flaps are a method of transferring skin with an intact blood supply from a nearby region of the body. An example of such reconstruction is a pedicled forehead flap for repair of a large nasal skin defect. Once the flap develops a source of blood supply form its new bed, the vascular pedicle can be detached.^[53]

Prognosis[edit]

The mortality rate of basal-cell and squamous-cell carcinoma is around 0.3%, causing 2000 deaths per year in the US. In comparison, the mortality rate of melanoma is 15–20% and it causes 6500 deaths per year.^[54]:29,31 Even though it is much less common, malignant melanoma is responsible for 75% of all skin cancer-related deaths.^[55]

The survival rate for people with melanoma depends upon when they start treatment. The cure rate is very high when melanoma is detected in early stages, when it can easily be removed surgically. The prognosis is less favorable if the melanoma has spread to other parts of the body.^[56] As of 2003 the overall five year cure rate with Mohs' micrographic surgery was around 95 percent for recurrent basal cell carcinoma.^[57]

Australia and New Zealand exhibit one of the highest rates of skin cancer incidence in the world, almost four times the rates registered in the United States, the UK and Canada. Around 434,000 people receive treatment for non-melanoma skin cancers and 10,300 are treated for melanoma. Melanoma is the most common type of cancer in people between 15–44 years in both countries. The incidence of skin cancer has been increasing.^[58] The incidence of melanoma among Auckland residents of European descent in 1995 was 77.7 cases per 100,000 people per year, and was predicted to increase in the 21st century because of "the effect of local stratospheric ozone depletion and the time lag from sun exposure to melanoma development."^[59]

Epidemiology[edit]

Age-standardized death from melanoma and other skin cancers per 100,000 inhabitants in 2004^[60]

no data   <0.7   0.7–1.4   1.4–2.1   2.1–2.8   2.8–3.5   3.5–4.2

4.2–4.9   4.9–5.6   5.6–6.3   6.3–7   7–7.7   >7.7

Skin cancers result in 80,000 deaths a year as of 2010, 49,000 of which are due to melanoma and 31,000 of which are due to non-melanoma skin cancers.^[61] This is up from 51,000 in 1990.^[61]

More than 3.5 million cases of skin cancer are diagnosed annually in the United States, which makes it the most common form of cancer in that country. One in five Americans will develop skin cancer at some point of their lives. The most common form of skin cancer is basal-cell carcinoma, followed by squamous cell carcinoma. Unlike for other cancers, there exists no basal and squamous cell skin cancers registry in the United States.^[62]

Melanoma[edit]

In the US in 2008, 59,695 people were diagnosed with melanoma, and 8,623 people died from it.^[63] In Australia more than 12,500 new cases of melanoma are reported each year, out of which more than 1,500 die from the disease. Australia has the highest per capita incidence of melanoma in the world.^[64]

Although the rates of many cancers in the United States is falling, the incidence of melanoma keeps growing, with approximately 68,729 melanomas diagnosed in 2004 according to reports of the National Cancer Institute.^[65]

Melanoma is the fifth most common cancer in the UK (around 13,300 people were diagnosed with melanoma in 2011), and the disease accounts for 1% all cancer deaths (around 2,100 people died in 2012).^[66]

Non-melanoma[edit]

Approximately 2,000 people die from basal or squamous cell skin cancers (non-melanoma skin cancers) in the United States each year. The rate has dropped in recent years. Most of the deaths happen to people who are elderly and might not have seen a doctor until the cancer had spread; and people with immune system disorders.^[62]