Brandon Skin cancers account for nearly one-third of all cancers diagnosed in the U. S. each year.1 This accounts for nearly 800,000 new cases each year.1 Basal cell carcinomas are comprised of basal cells, which are found in the basal layer of the skin.1 The epidermis is made up of two basic layers. The outermost layer is the stratum corneum and the basement layer is know as the basal layer which divides the epidermis from the dermis of the skin.1
Etiology:
Brandon As skin cancer is one of the most common cancers, we are all aware of the risk factors associated with them. However, here are some factors that may place individuals at risk for developing basal cell carcinoma:1
Exposure to solar radiation (most common)
Ionizing radaiation
Genetic predisposition
Arsenic exposure
Preexisting chronic skin ulcers
Human Papillomavirus (HPV)
Signs & Symptoms:
Ashley Signs and symptoms of basal cell can resemble several other skin conditions or cancers. Early detection of these symptoms is key to early treatment and cure. One sign of basal cell carcinoma is an open sore on the skin that oozes, is sore, or remains apparent even after several weeks. 2 Another sign/symptom of basal cell is the presence of a reddish patch that resembles a rash.2 The patch may itch or be otherwise asymptomatic. Patients may also notice a shiny bump or nodule that is translucent and can range in colors from pink to black.2 The image below demonstrates this characteristic. Finally, a scar-like lesion can be representative of basal cell carcinoma. The lesion has irregular borders and is often much bigger then what is seen on the face of the skin. 2
Figure 1. Reprinted from Skin Cancer Foundation Web site. 2
Diagnostic Procedures:
Ashley The diagnosis of most skin cancers begins with a self-examination. Most patients will notice a mole or other patch of skin change colors, borders or become irregular. Once the patient reports the abnormality to their physician, the doctor examines the area and gets an extensive history to determine the likelihood of cancer development. 2 The most common questions involve family history and sun exposure. If the doctor suspects the lesion is suspicious, a biopsy is ordered to determine if a malignancy is present. 2
Histology:
Amanuel There is no specific generally accepted classification of basal cell carcinoma. Most classifications are based on growth pattern of the tumor. The most basic histological types are:3
Nodular type [solid] – in 30-75% of all BCC
Superficial type [multicentric, multifocal] – 10-15% of all BCC
Infiltrative – 10% of all BCC
Lymph node drainage:
Amanuel It is very rare for basal cell carcinoma to spread to lymph nodes.4 The drainage sites depend on the location of the original diagnosis.
Metastatic spread:
Lindsey Basal cell carcinomas rarely metastasize.5 The most common site for skin cancer metastasis is in the lymph nodes, but this is rarely seen in basal cell carcinomas, whereas it is more commonly found with melanoma and sometimes squamos cell carcinomas.
Grading:
Lindsey If grading is not specified for a given tumor, the following system is commonly used:6 Gx: undetermined grade G1: well differentiated---low grade G2: moderately differentiated---intermediate grade G3: poorly differentiated---high grade G4: undifferentiated---high grade
Staging:
Kevin
The American Joint Committee on Cancer’s (AJCC) TNM system is used to stage basal and squamous cell skin cancers.T= tumor size, location, and spread in to nearby tissues.7
TX: primary tumor can’t be assessed.
TO: no evidence of primary tumor
Tis: Carcinoma in situ
T1: Tumor is 2cm across or smaller and has only one high risk feature.
T2: larger than 2cm across or has 2 or more high risk features.
T3: Invades facial bones
T4: invades bones of the body or base of skull
High risk features of tumors that are used to distinguish T1 and T2
Thicker than 2mm
Invaded in to lower dermis or subcutis
Invaded tiny nerves if the skin
Originates from the ear or hair-bearing lip
Poorly differentiated or undifferentiated under microscope
N= Nodal involvement
NX: nearby nodes can’t be assessed
NO: No spread to nearby nodes
N1: 1 nearby node on the same side of the body as the primary and 3cm or less across
N2a: 1 node same side as primary and between 3 and 6cm across
N2b: more than 1 node on the same side as the primary, none larger than 6cm
N2c: spread to nodes on the opposite side of the body and none larger than 6cm
Erythema of the treated area is the earliest side effect
Dermatitis dependent of the dosage and energy used
Dry desquamation
Moist desquamation
Burning and itching symptoms
Radiation necrosis(usually in higher fractional doses)8
Prognosis:
Jenn For most BCC surgical treatments or radiation therapy offer equivalent excellent cure rates of 90% to 95%.9
Treatments:
Jenn Treatment options include:
Mohs Micrographic Surgery: using local anesthesia the physician removes the tumor with a very thin layer of tissue around it. The layer is immediately checked under microscope thoroughly. If tumor is still present in the depths or peripheries of this surrounding tissue, the procedure is repeated until the last layer examined under the microscope is tumor-free.10
Excisional Surgery; using local anesthesia, the physician scrapes off the cancerous growth with a sharp ring shaped instrument.10
Radiation: may offer an advantage over surgical techniques with respect to cosmesis and function. Most skin cancers are treated with electrons. For most tumors, the electron beam energy is selected based on delivering the treatment to the 90% isodose line. Bolus is usually used to enhance surface dose. For more advanced lesions with deep penetration and involvement of bone or cartilage, photon beams with bolus can be employed in conjunction with electrons. Daily treatment fractions generally range from 2 to 5 Gy, with total tumor doses of 30 to 50 Gy in 6 to 20 fractions for most basal cell carcinomas.9
Cryosurgery: freezing with liquid nitrogen destroys tumor tissue, without the need for cutting or anesthesia.10
Photodynamic Therapy: PDT can be useful when patients have multiple BCCs. A photosensitizing agent such as Topical 5-aminolevulinic acids is applied to the tumors. The abnormal cells take it up. The next day, the patient returns to physician’s office and a strong light activates the medicated areas. This treatment selectively destroys BCCs while causing minimal damage to surrounding tissue.10
Topical Medications: FDA approved cream is rubbed gently into the tumor five times a week for up to six weeks or longer. This is only for superficial BCC’s.10
*
TD 5/5:
Rachel
The TD 5/5 for skin is 55 Gy.11 Telangiectasia and fibrosis are seen with doses to skin of over 45 Gy and are likely with doses over 65 Gy. Skin necrosis is the most severe late effect and is seen with doses over 55 Gy.
References:
Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd ed. Philadelphia: Lippincott, Williams & Wilkins, 2002. 111.
Skin cancers account for nearly one-third of all cancers diagnosed in the U. S. each year.1 This accounts for nearly 800,000 new cases each year.1 Basal cell carcinomas are comprised of basal cells, which are found in the basal layer of the skin.1 The epidermis is made up of two basic layers. The outermost layer is the stratum corneum and the basement layer is know as the basal layer which divides the epidermis from the dermis of the skin.1
As skin cancer is one of the most common cancers, we are all aware of the risk factors associated with them. However, here are some factors that may place individuals at risk for developing basal cell carcinoma:1
Signs and symptoms of basal cell can resemble several other skin conditions or cancers. Early detection of these symptoms is key to early treatment and cure. One sign of basal cell carcinoma is an open sore on the skin that oozes, is sore, or remains apparent even after several weeks. 2 Another sign/symptom of basal cell is the presence of a reddish patch that resembles a rash.2 The patch may itch or be otherwise asymptomatic. Patients may also notice a shiny bump or nodule that is translucent and can range in colors from pink to black.2 The image below demonstrates this characteristic. Finally, a scar-like lesion can be representative of basal cell carcinoma. The lesion has irregular borders and is often much bigger then what is seen on the face of the skin. 2
The diagnosis of most skin cancers begins with a self-examination. Most patients will notice a mole or other patch of skin change colors, borders or become irregular. Once the patient reports the abnormality to their physician, the doctor examines the area and gets an extensive history to determine the likelihood of cancer development. 2 The most common questions involve family history and sun exposure. If the doctor suspects the lesion is suspicious, a biopsy is ordered to determine if a malignancy is present. 2
There is no specific generally accepted classification of basal cell carcinoma. Most classifications are based on growth pattern of the tumor.
The most basic histological types are:3
It is very rare for basal cell carcinoma to spread to lymph nodes.4 The drainage sites depend on the location of the original diagnosis.
Basal cell carcinomas rarely metastasize.5 The most common site for skin cancer metastasis is in the lymph nodes, but this is rarely seen in basal cell carcinomas, whereas it is more commonly found with melanoma and sometimes squamos cell carcinomas.
If grading is not specified for a given tumor, the following system is commonly used:6
Gx: undetermined grade
G1: well differentiated---low grade
G2: moderately differentiated---intermediate grade
G3: poorly differentiated---high grade
G4: undifferentiated---high grade
The American Joint Committee on Cancer’s (AJCC) TNM system is used to stage basal and squamous cell skin cancers.T= tumor size, location, and spread in to nearby tissues.7
- TX: primary tumor can’t be assessed.
- TO: no evidence of primary tumor
- Tis: Carcinoma in situ
- T1: Tumor is 2cm across or smaller and has only one high risk feature.
- T2: larger than 2cm across or has 2 or more high risk features.
- T3: Invades facial bones
- T4: invades bones of the body or base of skull
High risk features of tumors that are used to distinguish T1 and T2- Thicker than 2mm
- Invaded in to lower dermis or subcutis
- Invaded tiny nerves if the skin
- Originates from the ear or hair-bearing lip
- Poorly differentiated or undifferentiated under microscope
N= Nodal involvement- NX: nearby nodes can’t be assessed
- NO: No spread to nearby nodes
- N1: 1 nearby node on the same side of the body as the primary and 3cm or less across
- N2a: 1 node same side as primary and between 3 and 6cm across
- N2b: more than 1 node on the same side as the primary, none larger than 6cm
- N2c: spread to nodes on the opposite side of the body and none larger than 6cm
- N3: any node is larger than 6cm across
M= Metastasis or spread to distant organshttp://www.cancer.gov/cancertopics/factsheet/detection/staging
For most BCC surgical treatments or radiation therapy offer equivalent excellent cure rates of 90% to 95%.9
Treatment options include:
- Mohs Micrographic Surgery: using local anesthesia the physician removes the tumor with a very thin layer of tissue around it. The layer is immediately checked under microscope thoroughly. If tumor is still present in the depths or peripheries of this surrounding tissue, the procedure is repeated until the last layer examined under the microscope is tumor-free.10
- Excisional Surgery; using local anesthesia, the physician scrapes off the cancerous growth with a sharp ring shaped instrument.10
- Radiation: may offer an advantage over surgical techniques with respect to cosmesis and function. Most skin cancers are treated with electrons. For most tumors, the electron beam energy is selected based on delivering the treatment to the 90% isodose line. Bolus is usually used to enhance surface dose. For more advanced lesions with deep penetration and involvement of bone or cartilage, photon beams with bolus can be employed in conjunction with electrons. Daily treatment fractions generally range from 2 to 5 Gy, with total tumor doses of 30 to 50 Gy in 6 to 20 fractions for most basal cell carcinomas.9
- Cryosurgery: freezing with liquid nitrogen destroys tumor tissue, without the need for cutting or anesthesia.10
- Photodynamic Therapy: PDT can be useful when patients have multiple BCCs. A photosensitizing agent such as Topical 5-aminolevulinic acids is applied to the tumors. The abnormal cells take it up. The next day, the patient returns to physician’s office and a strong light activates the medicated areas. This treatment selectively destroys BCCs while causing minimal damage to surrounding tissue.10
- Topical Medications: FDA approved cream is rubbed gently into the tumor five times a week for up to six weeks or longer. This is only for superficial BCC’s.10
*The TD 5/5 for skin is 55 Gy.11 Telangiectasia and fibrosis are seen with doses to skin of over 45 Gy and are likely with doses over 65 Gy. Skin necrosis is the most severe late effect and is seen with doses over 55 Gy.
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