Basal cell carcinoma ( BCC ), also known as basal cell cancer , is the most common type of skin cancer. Often appear as a painless skin area, which may glow with small blood vessels that pass through it; or may appear as areas raised with ulceration. Basal cell cancer grows slowly and can damage nearby tissue but is unlikely to spread to distant areas or cause death.
Risk factors include exposure to ultraviolet light, have lighter skin, radiation therapy, long-term exposure to arsenic, and poor immune system function. UV exposure during childhood is very dangerous. Tanning beds have been a common source of ultraviolet radiation. Diagnosis often depends on skin examination, confirmed by tissue biopsy.
It remains unclear whether sunscreens affect the risk of basal cell cancer. Treatment is usually performed by surgical removal. This can be a simple excision if the cancer is small; otherwise, the Mohs operation is generally recommended. Other options may include application of cold chemotherapy, topical, laser surgery, or imiquimod use. In rare cases where remote spread has occurred, chemotherapy or targeted therapy may be used.
Basal cell cancer accounts for at least 32% of all cancers globally. Of skin cancers other than melanoma, about 80% are basal cell cancers. In the United States about 35% of white men and 25% of white women are affected by BCC at some point in their lives.
Video Basal-cell carcinoma
Signs and symptoms
Individuals with basal cell carcinoma usually present with shiny and shiny skin nodules. However, superficial basal cell cancer may present as a red patch similar to eczema. Infiltrative or morpheaform cell-basal cells may present as skin thickening or scarring - making diagnosis difficult without the use of tactile sensation and skin biopsy. It is often difficult to visually distinguish basal cancer cells from acne scars, actinic elastosis, and recent cryodestruction inflammation.
Maps Basal-cell carcinoma
Cause
About two-thirds of basal cell carcinomas occur in areas of the body exposed to sunlight. A third occurs in areas of the body that are not exposed to sunlight, emphasizing the genetic susceptibility of basal cell cancer.
Pathophysiology
Basal cell carcinoma is presently thought to be derived from the folliculo-sebaceous-apocrine germ, also known as the trichoblast. The differential diagnosis with trichoblastic carcinoma, a rare malignant form of trichoblastoma, can be a challenge. Alternatively, one argument is that basal cell carcinoma is trichoblastic carcinoma. Overexposure to the sun leads to the formation of thymine dimers, a form of DNA damage. While DNA repair removes most UV damage, not all cross links are cut off. Therefore, cumulative DNA damage causes mutations. Regardless of mutagenesis, overexposure to sunlight suppresses the local immune system, possibly reducing immune surveillance for new tumor cells.
Basal cell carcinoma can often be associated with other lesions of the skin, such as actinic keratosis, seborrhoeic keratosis, squamous cell carcinoma. In a minority of cases, basal cell carcinoma also develops as a result of basal cell nevus syndrome, or Gorlin's syndrome, which is also characterized by keratocyst odontogenic tumors of the jaw, palmar or plantar (palmar) hole, falx cerebrial calcification (in the midline of the brain) and bone abnormalities. The cause of this syndrome is a mutation in the PTCH1 tumor suppressor gene located on chromosome 9q22.3, which inhibits the hedgehog signaling pathway. A mutation in the SMO gene, which is also on the hedgehog line, also causes basal cell carcinoma.
Diagnosis
To diagnose basal cell carcinoma, skin biopsy was performed for histopathologic analysis. The most common method is a shaved biopsy under local anesthesia. Most nodular basal cell cancers can be diagnosed clinically; however, other variants can be very difficult to distinguish from benign lesions such as intradermal nevus, sebaceoma, fibrous fibula, early acne scars, and hypertrophic scarring.
Classification
Basal cell carcinoma can be divided into three groups, based on growth patterns.
- Superficial basal cell carcinoma, previously called basal cell carcinoma in-situ, is characterized by superficial proliferation of neoplastic basal cells. These tumors are generally responsive to chemotherapy topics, such as Aldara (Imiquimod), or Fluorouracil.
- Infiltrative basal cell carcinoma, which also includes morpheaform and micronodular basal cell cancer, is more difficult to treat with conservative methods, given its tendency to penetrate deeper layers of the skin.
- Nodular basal cell carcinoma covers most of the remaining basal cell cancer categories. It's not uncommon to find heterogeneous morphological features in the same tumor.
Histopathology classification
Histopathology classification includes:
- Nodular basal cell carcinoma (also known as "classical basal cell carcinoma") is most common in areas exposed to sunlight on the head and neck.
- Cystic basal cell carcinoma is morphologically characterized by a dome-shaped blue dome cyst node.
- Chiratricial basal cell carcinoma (also known as "morpheaform basal cell carcinoma," and "morphologic basal cell carcinoma") is an aggressive variant with distinct clinical and histologic features.
- Infiltrative basal cell carcinoma is an aggressive type characterized by deep infiltration.
- Micronodular basal cell carcinoma is characterized by a micronodular growth pattern.
- Superficial basal cell carcinoma (also known as "superficial multisental cell carcinoma") is most common in the trunk and appears as erythematous patches.
- Basal basal cell carcinoma indicates an increase in melanization. About 80% of all basal cell carcinomas in China are pigmented while this subtype is rare in whites.
- Rodent ulcers (also known as "Jacob ulcers") are large skin lesions of nodular basal cell carcinoma with central necrosis. Almost all cancases metastasize except glioma (central nervous system malfunction) and rodent ulcers.
- Fibroepithelioma of Pinkus is most common in the lower back.
- Polipoid basal cell carcinoma is characterized by eco-like nodules (polypoid structures) in the head and neck.
- Basal cell carcinoma like-pore resembles an enlarged pore or an enlarged suit.
- Aberrant basal cell carcinoma is characterized by the formation of basal cell carcinoma in the absence of carcinogenic factors, occurring in strange places such as scrotum, vulva, perineum, nipple, and axilla.
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Pencegahan
Basal cell carcinoma is a common skin cancer and occurs mainly in white patients with a family history of this cancer. Sunlight is a factor in about two-thirds of these cancers; Therefore, doctors recommend sunscreen with at least an SPF of 30. However, Cochrane reviews that examine the effects of sun protection (sunscreen only) in preventing the development of basal cell carcinoma or skin cell squamous carcinoma find that there is not enough evidence to show whether sunscreens are effective for the prevention of one of these inherited keratinocyte cancers. This study finally states that the certainty of these results is low, so the evidence of the future is very likely to change this conclusion. One-third occur in areas not exposed to sunlight; thus, the pathogenesis is more complex than UV exposure as the cause .
The use of chemotherapy agents such as 5-Fluorouracil or imiquimod, can prevent the development of skin cancer. It is usually recommended for individuals with extensive sun damage, a history of multiple skin cancers, or an imperfect form of cancer (ie, sun keratosis). It is often repeated every 2 to 3 years to further reduce the risk of skin cancer.
Treatment
The following methods are used in the treatment of basal cell carcinoma (BCC):
Surgery
Standard surgical excision
This can be by frozen histology, or tissue pathology remains ingrained paraffin. This is the preferred method of removing most BCCs. Dermatoscopes can help experienced surgeons accurately identify a visible tumor that the naked eye can not see.
The healing rate for this method, whether performed by General Surgeon, Otolaryngologist, Head & amp; Neck Surgery, Plastic Surgeon, Maxillofacial Surgeon or Dermatologist really depends on the surgical limit. The narrower the limit of free surgery (removal of the free skin of the visible tumor) the higher the recurrence rate. If a 4 mm free operation limit is obtained around a small tumor (less than 6 mm), or a larger 6 mm free sperm margin is obtained around a larger tumor (greater than 6 mm), the healing rate is very high - 95% or more good. However, for cosmetic reasons, many doctors only take a very small surgical margin of 1-2 mm, especially when operating on the face. In such cases, the pathology report shows that the free margins of residual tumors are often inaccurate, and the recurrence rate is much higher (up to 38%).
The disadvantage with standard surgical excision is the high recurrence rate of facial basal cell cancer, especially around the eyelid, nose, and facial structure. A diagram on page 38 of the National Comprehensive Cancer Network publication shows a high risk area of ​​recurrence as most faces with the exception of the center of the cheek and upper forehead. On the face, or on recurrent basal cell cancer after prior surgery, controlled processing of special surgical margins (CCPDMA - complete circumference and complete inner circumference) using frozen histology (Mohs surgery is one method) is required.
With marginal surgery controlled by frost histology, a surgeon can achieve a high cure rate and a low recurrence rate on the same day of excision. However, most of the standard excision performed in a plastic surgeon or dermatologist's office is sent to an outside laboratory for standard baking methods. With this method, less than 5% of the surgical margins are probed, since each slice of tissue is only 6 micrometers thick, about 3 to 4 series slices are obtained per section, and only about 3 to 4 parts are obtained. per specimen (see figure 2 reference).
If in doubt, a patient should insist that either Mohs surgery or histology of the frozen section with either margin control (ccpdma) or thin bread-buns series are used when dealing with tumors on the face. The pathologist who processes the frozen part specimen must cut several sections through the block to minimize the false negative error rate. Or one should only process the network using methods approaching the Mohs method (described in the most basic histopathological textbook or described in this reference) during processing of the frozen section. Unfortunately, this method is difficult to apply to freezing; and they are very boring to process. When not using the frozen section, the surgeon may have to wait a week or more before telling the patient if more tumors are left, or if the surgical margin is too narrow. A second operation should be performed to remove residual residual or potential tumors after the surgeon informs the patient of a positive or narrow operative range on surgical pathology report.
A 2008 meta-literature study on BCC management suggests that excision is a good treatment for primary tumors.
Mohs Surgery
Mohs surgery (or Mohs microdermic surgery) is an outpatient procedure, developed by Frederic E. Mohs in the 1940s, in which tumors are surgically cut and then immediately examined under a microscope. This is a form of pathological processing called CCPDMA. Bases and edges are microscopically examined to verify sufficient margins before site repair surgery. If the margin is insufficient, more is excluded from the patient until the margin is sufficient. It is also used for squamous cell carcinoma; However, the healing rate is not as high as Mohs surgery for basal cell carcinoma. A 2008 study found MMS to be a good choice for primary and high risk recurrent BCC.
Cryosurgery
Cryosurgery is a long-standing modality for the treatment of many skin cancers. When accurately used with the temperature probe and cryotherapy instruments, it can produce an excellent healing rate. Disadvantages include lack of margin control, tissue necrosis, over or under tumor treatment, and long recovery time. Overall, there is sufficient data to consider cryosurgery as a reasonable treatment for BCC. No good study, however, compares cryosurgery with other modalities, especially with Mohs operations, excision, or electrodeskation and curettage so no conclusions can be made whether cryosurgery is as powerful as other methods. Also, there is no evidence whether shrinkage of lesions before cryosurgery affects the effectiveness of treatment. Some textbooks are published on therapy, and some doctors still apply treatments for selected patients.
Electrodication and curettage
Elektrodikasi and kuretase (EDC, also known as curettage and cautery, just curettage) is done by using a round blade, or curette, to erode soft cancer. The skin is then burned with electric current. This further softens the skin, allowing the blade to cut deeper with the next curette layer. This cycle is repeated, with the normal curette skin safety margin around the visible tumor. This cycle is repeated 3 to 5 times, and the free skin margins treated are usually 4 to 6 mm. The healing rate is highly dependent on the user and also depends on the size and type of tumor. Infiltrative or morpheaform BCC can be difficult to eradicate with EDC. Generally, this method is used in areas that are not cosmetically important such as trunk (the torso). Some doctors believe that the use of EDC is acceptable in elderly patients over the age of 70. However, with life expectancy increasing, such objective criteria can not be supported. The healing rate may vary, depending on the aggressiveness of EDC and the free margins being treated. Some advocate own curettage without electrodication, and with the same healing rate.
Chemotherapy
Some superficial cancers respond to local therapy with 5-fluorouracil, a chemotherapy agent. Topical treatment with Imiquimod cream 5%, with five applications per week for six weeks has a reported 70-90% success rate in reducing, even eliminating, BCC [basal cell carcinoma]. Both Imiquimod and 5-fluorouracil have received FDA approval, and topical IMQ is approved by the European Drug Agency for treatment of small superficial basal cell carcinomas. The use of outer imiquimod labels on invasive basal cell carcinomas has been reported. Imiquimod may be used before surgery to reduce the size of carcinoma. One can expect a lot of inflammation with this treatment. Chemotherapy often follows Mohs surgery to remove superficial basal cell carcinoma after the invasive part is removed. Some advocate the use of imiquimod before Mohs surgery to remove the superficial component of the cancer. Removing a residual superficial tumor by surgery alone can cause major surgical damage and is difficult to repair. A person often waits a month or more after surgery before starting Imiquimod or 5-fluorouracil to ensure the wound surgery has healed adequately. Some people advocate the use of curettes (see EDC below) first, followed by chemotherapy. This experimental procedure is not a standard treatment. The 2008 study reported that topical IMQ appears effective in the treatment of small primary superficial BCC, but only 'may' have a role in the treatment of primary nodular BCC.
Approved in 2012, vismodegib is used to treat advanced forms of basal cell carcinoma.
Immunotherapy
Immunotherapy studies have shown that treatment using Euphorbia peplus , common garden plants, may be effective. Australian biopharmaceutical company Peplin developed this as a topical treatment for BCC. Imiquimod is immunotherapy but is listed here under chemotherapy.
Radiation
Radiation therapy may be administered either as an external beam radiotherapy or as brachytherapy (internal radiotherapy). Although radiotherapy is commonly used in older patients who are not candidates for surgery, it is also used in cases where surgical excision is damaging or difficult to reconstruct (especially on the tip of the nose, and the nose rim). Radiation treatments often take at least 5 visits to as many as 25 visits. Usually, the more scheduled visits to therapy, the less complications or damage that occurs in normal tissue that support the tumor. Radiotherapy may also be useful if surgical excision has been performed incompletely or if pathology reports after surgery indicate a high risk of recurrence, eg if nerve involvement has been demonstrated. Cure rate can be as high as 95% for small tumors, or as low as 80% for large tumors. Typically, the tumor recurs after radiation is treated with surgery, and not by radiation. Further radiation treatment will further damage normal tissue, and tumors may be resistant to further radiation. Radiation therapy can be contraindicated for the treatment of nevoid basal cell carcinoma syndrome. The 2008 study reported that radiation therapy is a good treatment for primary BCC and recurrent BCC, but not for BCC recurrence after previous radiation treatments.
Photodynamic therapy
Photodynamic therapy (PDT) is a new modality for the treatment of basal cell carcinoma, administered by the photosensitizer application to the target area. When these molecules are activated by light, they become toxic, because it destroys the target cell. Methyl aminolevulinate is approved by the EU as a photosensitizer since 2001. This therapy is also used in other types of skin cancer. The 2008 study reported that PDT is a good treatment option for primary superficial BCC, makes sense for primary low risk nodular BCC, but a 'relatively poor' option for high-risk lesions.
Prognosis
The prognosis is excellent if appropriate treatment methods are used early in primary basal cell cancer. Recurrent cancer is more difficult to cure, with a higher recurrence rate with any treatment method. Although basal cell carcinoma rarely metastasizes, it grows locally by invasion and destruction of local tissues. Cancer can attack vital structures such as nerves and result in loss of sensation or loss of function or rarely death. Most cases can be successfully treated before serious complications occur. The relapse rate for the above treatment options ranges from 50 percent to 1 percent or less.
Epidemiology
Basal cell cancer is a very common skin cancer. This is more common in white individuals with a family history of basal cell cancer and increased incidence closer to the equator or at higher altitudes. There are about 800,000 new cases each year in the United States alone. Up to 30% of Caucasians develop basal cell carcinoma in their lifetime. In Canada, the most common skin cancer is basal cell carcinoma (as much as one-third of all cancer diagnoses), affecting 1 in 7 individuals during a lifetime.
In the United States about 3 out of 10 caucasians develop basal cell carcinoma during their lifetime. These tumors account for about 70% of non-melanoma skin cancers. In 80 percent of all cases, basal cell carcinoma affects the scalp and neck. In addition, there appears to be an increased incidence of basal cell cancer in stems in recent years.
Most sporadic BCCs appear in small amounts on sun-exposed skin in people over 50, although younger people may also be affected. The development of some basal cell cancers at an early age may be an indication of nevoid basal cell carcinoma syndrome, also known as Gorlin Syndrome.
References
External links
Source of the article : Wikipedia
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