Breslow's depth |
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In medicine, Breslow's depth was used as a prognostic factor in melanoma of the skin. It is a description of how deeply tumor cells have invaded. Currently, the standard Breslow's depth has been replaced by the AJCC depth, in the AJCC staging system of melanoma. Originally, Breslow's depth was divided into 5 stages. [1]
Stage | Depth |
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Stage I | 0.75mm or less |
Stage II | 0.76 mm - 1.50mm |
Stage III | 1.51mm - 4.00 mm |
Stage IV | >4mm |
Depth of invasion was first reported as a prognostic factor in melanoma by the pathologist Alexander Breslow, M.D. at George Washington University in 1970. [1] In recognition of his contribution, the depth of invasion of melanoma is referred to by the eponym Breslow's depth.
Subsequent studies confirmed and refined the role of depth of invasion in the prognosis of malignant melanoma. [2] [3] Currently, Breslow's depth is included in the AJCC staging guidelines for melanoma as a major prognostic factor.
Tumor depth is most accurately measured by evaluating the entire tumor via an excisional biopsy. Determination from specimens obtained using other biopsy techniques, such as a wedge or punch biopsy, are less accurate. Tumor depth cannot be calculated from a shave biopsy that only contains a portion of the tumor because it leads to an underestimation of its thickness.
Breslow's depth is determined by using an ocular micrometer at a right angle to the skin to directly measure the depth to which tumor cells have invaded the skin. Breslow's depth is measured from the granular layer of the epidermis down to the deepest point of invasion (sometimes involving detached nests of cells).
Tumor depth is one of the cornerstones of the current AJCC TNM staging of malignant melanoma. A large study validated the importance of tumor depth (but not Breslow's original description) as one of the three most important prognostic factors in melanoma (the others being T stage and ulceration). [4] Breslow's depth also accurately predicted the risk for lymph node metastasis, with deeper tumors being more likely to involve the nodes. [5]
The above studies showed that depth was a continuous variable correlating with prognosis. However, for staging purposes, the most recent AJCC guidelines use cutoffs of 1 mm, 2 mm, and 4 mm to divide patients into stages.
Tumor Depth | Approximate 5 year survival |
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< 1 mm | 95–100% |
1–2 mm | 80–96% |
2.1–4 mm | 60–75% |
> 4 mm | 50% |
Survival figures from British Association of Dermatologist Guidelines, 2002
Clark's level is a related staging system, used in conjunction with Breslow's depth, which describes the level of anatomical invasion of the melanoma in the skin. [6] Clark's level was the primary factor in earlier AJCC staging schemas for melanoma. [ citation needed ] However, with further study, it has been shown that Clark's level has a lower predictive value, is less reproducible, and is more operator-dependent as compared with Breslow's depth. [ citation needed ] Thus, in the current (2010) AJCC staging system, Clark's level has prognostic significance only in patients with very thin (Breslow depth <1 mm) melanomas. [4]
Five anatomical levels are recognized, and higher levels have worsening prognostic implications. These levels are:
Cutaneous squamous-cell carcinoma (cSCC), or squamous-cell carcinoma of the skin, also known as squamous-cell skin cancer, is, with basal-cell carcinoma and melanoma, one of the three principal types of skin cancer. cSCC typically presents as a hard lump with a scaly top layer, but it may instead form an ulcer. Onset often occurs over a period of months. Cutaneous squamous-cell carcinoma is more likely to spread to distant areas than basal cell cancer. When confined to the outermost layer of the skin, a pre-invasive, or in situ, form of cSCC is known as Bowen's disease.
The TNM Classification of Malignant Tumors (TNM) is a globally recognised standard for classifying the anatomical extent of the spread of malignant tumours (cancer). It has gained wide international acceptance for many solid tumor cancers, but is not applicable to leukaemia or tumors of the central nervous system. Most common tumors have their own TNM classification. The TNM staging system is sometimes referred to as the AJCC/UICC staging system or the UICC/AJCC staging system.
Melanoma, also redundantly known as malignant melanoma, is a type of cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye. In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown.
Angiosarcoma is a rare and aggressive cancer that starts in the endothelial cells that line the walls of blood vessels or lymphatic vessels. Since they are made from vascular lining, they can appear anywhere and at any age, but older people are more commonly affected, and the skin is the most affected area, with approximately 60% of cases being cutaneous. Specifically, the scalp makes up ~50% of angiosarcoma cases, but this is still <0.1% of all head and neck tumors. Since angiosarcoma is an umbrella term for many types of tumor that vary greatly in origin and location, many symptoms may occur, from completely asymptomatic to non-specific symptoms like skin lesions, ulceration, shortness of breath and abdominal pain. Multiple-organ involvement at time of diagnosis is common and makes it difficult to ascertain origin and how to treat it.
Cancer staging is the process of determining the extent to which a cancer has grown and spread. A number from I to IV is assigned, with I being an isolated cancer and IV being a cancer that has metastasized and spread from its origin. The stage generally takes into account the size of a tumor, whether it has invaded adjacent organs, how many regional (nearby) lymph nodes it has spread to, and whether it has appeared in more distant locations (metastasized).
Superficial spreading melanoma (SSM) is a type of skin cancer that typically starts as an irregularly edged dark spot typically on sun-exposed part of the body. The colour may be variable with dark, light and reddish shades; occasionally no color at all. It typically grows in diameter before spreading to deeper tissue, forming a bump or becoming an ulcer. Itching, bleeding and crust formation may occur in some. The backs and shoulders of males and legs of women are particularly prone.
Lymph node biopsy is a test in which a lymph node or a piece of a lymph node is removed for examination under a microscope.
Invasive carcinoma of no special type (NST) is also referred to as invasive ductal carcinoma or infiltrating ductal carcinoma(IDC) and invasive ductal carcinoma, not otherwise specified (NOS). Each of these terms represents to the same disease entity, but for international audiences this article will use invasive carcinoma NST because it is the preferred term of the World Health Organization (WHO).
Merkel-cell carcinoma (MCC) is a rare and aggressive skin cancer occurring in about three people per million members of the population. It is also known as cutaneous APUDoma, primary neuroendocrine carcinoma of the skin, primary small cell carcinoma of the skin, and trabecular carcinoma of the skin. Factors involved in the development of MCC include the Merkel cell polyomavirus, a weakened immune system, and exposure to ultraviolet radiation. Merkel-cell carcinoma usually arises on the head, neck, and extremities, as well as in the perianal region and on the eyelid. It is more common in people over sixty years old, Caucasian people, and males. MCC is less common in children.
The sentinel lymph node is the hypothetical first lymph node or group of nodes draining a cancer. In case of established cancerous dissemination it is postulated that the sentinel lymph nodes are the target organs primarily reached by metastasizing cancer cells from the tumor.
Prostate cancer staging is the process by which physicians categorize the risk of cancer having spread beyond the prostate, or equivalently, the probability of being cured with local therapies such as surgery or radiation. Once patients are placed in prognostic categories, this information can contribute to the selection of an optimal approach to treatment. Prostate cancer stage can be assessed by either clinical or pathological staging methods. Clinical staging usually occurs before the first treatment and tumour presence is determined through imaging and rectal examination, while pathological staging is done after treatment once a biopsy is performed or the prostate is removed by looking at the cell types within the sample.
Vulvar cancer is a cancer of the vulva, the outer portion of the female genitals. It most commonly affects the labia majora. Less often, the labia minora, clitoris, or vaginal glands are affected. Symptoms include a lump, itchiness, changes in the skin, or bleeding from the vulva.
Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose Mohs surgery.
Lung cancer staging is the assessment of the extent to which a lung cancer has spread from its original source. As with most cancers, staging is an important determinant of treatment and prognosis. In general, more advanced stages of cancer are less amenable to treatment and have a worse prognosis.
Breast cancer classification divides breast cancer into categories according to different schemes criteria and serving a different purpose. The major categories are the histopathological type, the grade of the tumor, the stage of the tumor, and the expression of proteins and genes. As knowledge of cancer cell biology develops these classifications are updated.
Sebaceous carcinoma, also known as sebaceous gland carcinoma (SGc), sebaceous cell carcinoma, and meibomian gland carcinoma is an uncommon malignant cutaneous tumor. Most are typically about 1.4 cm at presentation. SGc originates from sebaceous glands in the skin and, therefore, may originate anywhere in the body where these glands are found. SGc can be divided into 2 types: periocular and extraocular. The periocular region is rich in sebaceous glands making it a common site of origin. The cause of these lesions in the vast majority of cases is unknown. Occasional cases may be associated with Muir-Torre syndrome. SGc accounts for approximately 0.7% of all skin cancers, and the incidence of SGc is highest in Caucasian, Asian, and Indian populations. Due to the rarity of this tumor and variability in clinical and histological presentation, SGc is often misdiagnosed as an inflammatory condition or a more common neoplasm. SGc is commonly treated with wide local excision or Mohs micrographic surgery, and the relative survival rates at 5 and 10 years are 92.72 and 86.98%, respectively.
Clark's level is a staging system, which describes the level of anatomical invasion of the melanoma in the skin. It was developed by Wallace H. Clark Jr. at Harvard University and Massachusetts General Hospital in the 1960s.
Animal-type melanoma is a rare subtype of melanoma that is characterized by heavily pigmented dermal epithelioid and spindled melanocytes. Animal-type melanoma is also known to be called equine-type melanoma, pigment synthesizing melanoma, and pigmented epithelioid melanocytoma (PEM). While melanoma is known as the most aggressive skin cancer, the mortality for PEM is lower than in other melanoma types. Animal-type melanoma earned its name due to the resemblance of melanocytic tumors in grey horses.
Wallace H. Clark Jr. was an American dermatologist and pathologist. He is best known for devising the "Clark's level", or Clark Level, system for classifying the seriousness of a malignant melanoma skin cancer based on its microscopic appearance.
CP-GEP is a non-invasive prediction model for cutaneous melanoma patients that combines clinicopathologic (CP) variables with gene expression profiling (GEP). CP-GEP is able to identify cutaneous melanoma patients at low-risk for nodal metastasis who may forgo the sentinel lymph node biopsy (SLNB) procedure. The CP-GEP model was developed by the Mayo Clinic and SkylineDx BV, and it has been clinically validated in multiple studies.