Skin cancer is a cancer that comes from the skin. They are caused by the development of abnormal cells that have the ability to attack or spread to other parts of the body. There are three main types of skin cancer: basal cell skin cancer (BCC), squamous cell skin cancer (SCC) and melanoma. The first two, along with a number of less common skin cancers, are known as nonmelanoma skin cancer (NMSC). Basal cell cancer grows slowly and can damage nearby tissue but is unlikely to spread to distant areas or cause death. Often it appears as an area of ​​painless skin, which may glow with small blood vessels that flow over it or may appear as an area that arises with the ulcer. Squamous cell skin cancer is more likely to spread. It usually appears as a hard lump with scaly peaks but can also form ulcers. Melanoma is the most aggressive. Signs including moles that have changed in size, shape, color, have irregular edges, have more than one color, itch or bleed.
More than 90% of cases are caused by exposure to ultraviolet radiation from the Sun. This exposure increases the risk of the three major types of skin cancer. Exposure has increased in part because of the thinner ozone layer. Tanning beds become another common source of ultraviolet radiation. For melanoma and cell-basal cell exposure during childhood is very dangerous. For squamous cell skin cancer, total exposure, regardless of when it occurs, is more important. Between 20% and 30% of melanomas develop from the mole. People with bright skin have a higher risk such as those who have poor immune function such as from drugs or HIV/AIDS. Diagnosis is done by biopsy.
Decreased exposure to ultraviolet radiation and the use of sunscreen seems to be an effective method to prevent melanoma and squamous cell skin cancer. It is unclear whether sunscreens affect the risk of basal cell cancer. Nonmelanoma skin cancer is usually curable. Treatment is generally done by surgical removal but may rarely involve radiation therapy or topical medications such as fluorouracil. The treatment of melanoma may involve several combinations of surgery, chemotherapy, radiation therapy, and targeted therapy. In people whose illness has spread to other areas of their body, palliative care may be used to improve quality of life. Melanoma has one of the higher survival rates among cancers, with over 86% of people in the UK and over 90% in the United States surviving more than 5 years.
Skin cancer is the most common form of cancer, globally accounting for at least 40% of cases. The most common type of skin cancer is nonmelanoma, which occurs in at least 2-3 million people per year. This is a rough estimate, because good statistics are not stored. Of nonmelanoma skin cancers, about 80% are basal cell cancers and 20% squamous cell skin cancers. Basal cell and squamous cell skin cancers rarely cause death. In the United States they are the cause of less than 0.1% of all cancer deaths. Globally in 2012 melanomas occur in 232,000 people, and result in 55,000 deaths. Australia and New Zealand have the highest levels of melanoma in the world. The three main types of skin cancer have become more common in the last 20 to 40 years, especially in areas where most Caucasians are.
Video Skin cancer
Classification
There are three main types of skin cancer: basal cell-cell cancer (basal cell carcinoma) (BCC), squamous cell skin cancer (squamous cell carcinoma) (SCC) and malignant melanoma.
Basal cell carcinoma is present in skin areas exposed to sunlight, especially the face. They rarely metastasize and rarely cause death. They are easily treated with surgery or radiation. Squamous cell skin cancer is common, but is much more common than basal cell cancer. They metastasize more often than BCC. Even then, the metastasis rate is quite low, with the exception of SCC in the lips, ears, and in immunosuppressed individuals. Melanoma is the most rare of 3 common skin cancers. They often metastasize, and potentially cause death once they spread.
Less common skin cancers include: dermatofibrosarcoma protuberans, Merkel cell carcinoma, Kaposi's sarcoma, keratoacanthoma, spindle cell tumor, sebaceous carcinoma, microcystic adnexa carcinoma, Paget disease of the breast, atypical fibroxanthoma, leiomiosarcoma, and angiosarcoma.
BCC and SCC often carry UV signature mutations that indicate that the cancer is caused by UVB radiation through direct DNA damage. However, malignant melanoma is mostly caused by UVA radiation through indirect DNA damage. Indirect DNA damage is caused by free radicals and reactive oxygen species. Research shows that the absorption of three sunscreens into the skin, combined with UV exposure for 60 minutes, leads to an increase in free radicals in the skin, if applied in too few and too rare. However, the researchers add that newer creams often do not contain these specific compounds, and that other ingredient combinations tend to retain compounds on the skin surface. They also added repeated applications that often reduce the risk of radical formation.
Maps Skin cancer
Signs and symptoms
There are different symptoms of skin cancer. These include changes to the skin that does not heal, skin ulcers, skin discoloration, and changes to the existing mole, such as the serrated tip to the mole and the enlargement of the mole.
Basal cell skin cancer
Basal cell skin cancer (BCC) usually appears as a prominent, smooth, and pearly lump on the scalp, neck or shoulders exposed to the sun. Sometimes small blood vessels (called telangiectasia) can be seen inside the tumor. Crusting and bleeding in the center of the tumor often develops. Often misunderstood as a pain that does not heal. This type of skin cancer is at least deadly and with the right treatment can be completely eliminated, often without scarring.
Squamous cell skin cancer
Squamous cell skin cancer (SCC) is usually a red, scaly, thickened patch on sun exposed skin. Some of these are hard nodules and domes that are shaped like keratoacanthomas. Ulceration and bleeding can occur. When SCC is not treated, it may develop into a large mass. Squamous cells are the second most common skin cancer. It's dangerous, but not as dangerous as melanoma.
Melanoma
Most melanomas consist of various colors from shades of brown to black. A small amount of melanoma is pink, red or fleshy; this is called amelanotic melanoma and tends to be more aggressive. Malignant melanoma warning signs include changes in size, shape, color or elevation of the mole. Other signs are the appearance of new moles during adulthood or pain, itching, ulceration, redness around the site, or bleeding at the site. The commonly used Mnemonic is "ABCDE", where A is for "asymmetric", B for "border" (irregular: "Maine Beach mark"), C for "color" (Diversity), D for "diameter" ( larger than 6 mm - pencil eraser size) and E to "evolve."
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Merkel cell carcinoma most often grows rapidly, red lumps, purple or unsound skin that is not painful or itchy. They may be misinterpreted as cysts or other types of cancer.
Cause
Ultraviolet radiation from exposure to sunlight is the main cause of skin cancer. Other risk factors that play a role include:
- Smoking tobacco
- HPV infection increases the risk of squamous cell skin cancer.
- Some genetic syndromes include congenital melanocytic na syndrome characterized by the presence of nevi (birthmark or mole) of various sizes present at birth, or appearing within 6 months of birth. Nevi larger than 20 mm (3/4 ") in higher-risk sizes to become cancerous.
- Wounds do not heal chronically. These are called Marjolin ulcers based on their appearance, and can progress to squamous cell skin cancer.
- Ionizing radiation such as X-rays, environmental carcinogens, artificial UV radiation (eg tanning beds), aging, and light skin tone. It is believed that tanning beds are the cause of hundreds of thousands of basal and squamous cell skin cancers. The World Health Organization now puts people who use artificial tanning beds in the highest risk category for skin cancer. Alcohol consumption, especially excessive drinking increases the risk of sunburn.
- The use of many immunosuppressive drugs increases the risk of skin cancer. Cyclosporin A, a calcineurin inhibitor, for example, increases the risk by about 200 times, and azathioprine is about 60 times.
Pathophysiology
Malignant epithelial tumors derived primarily from the epidermis, in the squamous mucosa or in the squamous metaplasia area are referred to as squamous cell carcinomas.
Macroscopically, tumors are often elevated, fungating, or may be ulcerated with irregular borders. Microscopically, tumor cells destroy the basement membrane and form sheets or compact masses that attack adjacent connective tissue (dermis). In well-differentiated carcinomas, tumor cells are pleomorphic/atypical, but resemble normal keratinocytes from the puncture layer (large, polygonal, with eosinophilic (pink) cytoplasm and abundant core centers).
Their disposal tends to resemble the normal epidermis: the immature/basal cells at the edges, becoming more mature to the center of tumor mass. The tumor cells turn into keratin squamous cells and form round nodules with concentric, layered layers, called "cell nests" or "epithelial/keratin pearls". The surrounding stroma is reduced and contains inflammatory infiltration (lymphocytes). Squamous squamous carcinomas contain more pleomorphic cells and without keratinization.
The molecular factors involved in the disease process are mutations in the PTCH1 gene that play an important role in the Sonic hedgehog signal path.
Prevention
Sunscreen is effective and thus recommended to prevent melanoma and squamous cell carcinoma. There is little evidence that it is effective in preventing basal cell carcinoma. Other suggestions for reducing levels of skin cancer include avoiding sunburn, wearing protective clothing, sunglasses and hats, and trying to avoid sun exposure or peak exposure periods. The US Preventive Services Task Force recommends that people between the ages of 9 and 25 are advised to avoid ultraviolet light.
The risk of developing skin cancer can be reduced through a number of steps including reducing indoor tanning and exposure to the midday sun, increasing the use of sunscreen, and avoiding the use of tobacco products.
There is no sufficient evidence to or against screening for skin cancer. Vitamin supplements and antioxidant supplements have not been found to have any effect in prevention. The evidence for the benefits of dietary action is tentative.
Zinc oxide and titanium oxide are often used in solar screens to provide extensive protection from the UVA and UVB ranges.
Eating certain foods can reduce the risk of sunburns but this is much less than the protection afforded by sunscreen.
Treatment
Treatment depends on the type of cancer, the location of the cancer, the age of the person, and whether the cancer is primary or recurrent. Treatment is also determined by specific types of cancer. For small basal cell cancer in young people, treatment with the best cure rate (Mohs or CCPDMA surgery) may be indicated. In the case of a weak old man with a variety of complicated medical problems, it is difficult to remove basal cell cancer from the nose may require radiation therapy (slightly lower healing rate) or no treatment at all. Topical chemotherapy may be indicated for large superficial basal cell carcinomas for good cosmetic results, whereas it may be inadequate for invasive nodular basal cell carcinoma or invasive squamous cell carcinoma. In general, melanomas are less responsive to radiation or chemotherapy.
For low-risk illnesses, radiation therapy (external beam radiotherapy or brachytherapy), topical chemotherapy (imiquimod or 5-fluorouracil) and cryotherapy can provide adequate control of the disease; all, however, may have an overall lower cure rate than certain types of surgery. Other treatment modalities such as photodynamic therapy, topical chemotherapy, electrodescation and curettage can be found in discussions of basal cell carcinoma and squamous cell carcinoma.
Mohs surgical microsurgery (surgical Mohs) is a technique used to remove cancer with at least surrounding tissue and the edges are examined immediately to see if a tumor is found. This provides an opportunity to wipe out the least amount of tissue and deliver cosmetically good results. This is very important for areas where the excess skin is limited, such as the face. The healing rate is equivalent to wide excision. Special training is required to perform this technique. The alternative method is CCPDMA and can be done by pathologists who are not familiar with Mohs operations.
In the case of a disease that has spread (metastasize), further surgical procedures or chemotherapy may be necessary.
Treatments for metastatic melanoma include ipilimumab biochemical immunotherapy agents, pembrolizumab, and nivolumab; BRAF inhibitors, such as vemurafenib and dabrafenib; and mEK trametinib inhibitors.
Reconstruction
Currently, surgical excision is the most common form of treatment for skin cancer. The purpose of reconstructive surgery is the recovery of appearance and normal function. The choice of technique in reconstruction is determined by the size and location of the defect. The excision and reconstruction of facial skin cancer is generally more challenging because of the presence of a highly visible and functional anatomical structure on the face.
When the skin defects are small in size, most can be repaired with a simple repair where the edges of the skin are approached and covered with stitches. This will produce a linear scar. If repairs are made along natural skin folds or wrinkles lines, scars will be hard to see. Larger defects may require repair by skin grafting, local skin flap, pedicled skin flap, or microvascular free flap. Skin grafts and local skin flaps are much more common than other options listed.
Skin grafting is a defect repair with the skin removed from other sites in the body. The skin grafts are stitched to the edges of the defect, and the guling pads are placed over the graft for seven to ten days, to paralyze the graft when he heals in place. There are two forms of skin grafts: split thickness and full thickness. In a split skin graft thickness, shavers are used to shave layers of skin from the stomach or thighs. The donor site regenerates the skin and heals for two weeks. In a full thick skin graft, the skin segment is completely removed and the donor site should be sewn closed.
Split split graft can be used to correct larger defects, but the graft is lower in cosmetic appearance. A full-thickness skin graft is more cosmetically acceptable. However, full thickness graft can only be used for small or medium-sized defects.
Local skin flap is a method of closing the defect with tissue that perfectly matches the color and quality defects. The skin from the periphery of disabled sites is mobilized and repositioned to fill the deficit. Various forms of local flap can be designed to minimize disruption to surrounding tissues and maximize the cosmetic results from reconstruction. The pedicled skin flap is a method of transferring the skin with intact blood supply from the nearby body area. An example of such reconstruction is a drilled forehead flap to repair large nasal skin defects. After the flap develops the source of blood supply to form a new bed, the vascular pedicle can be detached.
Prognosis
Basal cell death rate and squamous cell carcinoma are about 0.3%, causing 2000 deaths per year in the US. By comparison, the melanoma death rate is 15-20% and causes 6,500 deaths per year. Although much more rare, malignant melanoma is responsible for 75% of all skin cancer-related deaths.
The survival rate for people with melanoma depends when they start treatment. The healing rate is very high when melanoma is detected at an early stage, when it can be easily removed surgically. The prognosis is less favorable if melanoma has spread to other parts of the body. In 2003, the overall five-year healing rate with Mohs micrograph surgery was about 95 percent for recurrent basal cell carcinoma.
Australia and New Zealand show one of the highest rates of skin cancer incidence in the world, nearly four times the number registered in the United States, Britain and Canada. Approximately 434,000 people received treatment for non-melanoma skin cancer and 10,300 were 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 increased. The incidence of melanoma among the inhabitants of Auckland European descent in 1995 was 77.7 cases per 100,000 people per year, and is estimated to increase in the 21st century due to "the effect of local stratospheric ozone depletion and the lag time from sun exposure to the development of melanoma.
Epidemiology
Skin cancer produces 80,000 deaths per year in 2010, 49,000 of which are due to melanoma and 31,000 of which are caused by non-melanoma skin cancer. This is up from 51,000 in 1990.
More than 3.5 million cases of skin cancer are diagnosed each year in the United States, which makes it the most common form of cancer in the country. One in five Americans will develop skin cancer at some point in their lives. The most common form of skin cancer is basal cell carcinoma, followed by squamous cell carcinoma. Unlike for other cancers, there is no basal basal and squamous cell skin basalt in the United States.
Melanoma
In the US in 2008, 59,695 people were diagnosed with melanoma, and 8,623 people died from it. In Australia more than 12,500 new cases of melanoma are reported every year, where more than 1,500 people die from the disease. Australia has the highest incidence of melanoma per capita in the world.
Although many cancer rates in the United States declined, the incidence of melanoma continued to grow, with about 68,729 melanomas diagnosed in 2004 according to a report from the National Cancer Institute.
Melanoma is the fifth most common cancer in the UK (about 13,300 people diagnosed with melanoma in 2011), and it accounts for 1% of all cancer deaths (about 2,100 people died in 2012).
Non-melanoma
About 2,000 people die from basal cell or squamous cell skin cancer (non-melanoma skin cancer) in the United States each year. That number has declined in recent years. Most deaths occur in elderly people and may never see a doctor until the cancer spreads; and people with immune system disorders.
See also
- Physical hazard
References
External links
- Curlie skin cancer (based on DMOZ)
- Skin cancer procedures: text, images and video
Source of the article : Wikipedia
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