Breast cancers are described along four different classification schemes, or groups, each based on different criteria and serving a different purpose:
Pathology - A pathologist will categorize each tumor based on its histological (microscopic anatomy) appearance and other criteria. The most common pathologic types of breast cancer are invasive ductal carcinoma, malignant cancer in the breast's ducts, and invasive lobular carcinoma, malignant cancer in the breast's lobules.
Grade of tumor - The histological grade of a tumor is determined by a pathologist under a microscope. A well-differentiated (low grade) tumor resembles normal tissue. A poorly differentiated (high grade) tumor is composed of disorganized cells and, therefore, does not look like normal tissue. Moderately differentiated (intermediate grade) tumors are somewhere in between.
Protein & gene expression status - Currently, all breast cancers should be tested for expression, or detectable effect, of the estrogen receptor (ER), progesterone receptor (PR) and HER2/neu proteins. These tests are usually done by immunohistochemistry and are presented in a pathologist's report. The profile of expression of a given tumor helps predict its prognosis, or outlook, and helps an oncologist choose the most appropriate treatment. More genes and/or proteins may be tested in the future.
Stage of a tumour - The currently accepted staging scheme for breast cancer is the TNM classification.
There are five tumor classification values (Tis, T1, T2, T3 or T4) which depend on the presence or absence of invasive cancer, the dimensions of the invasive cancer, and the presence or absence of invasion outside of the breast (e.g. to the skin of the breast, to the muscle or to the rib cage underneath):
Tx - Primary tumor cannot be assessed.
T0 - No evidence of primary tumor.
Tis - Carcinoma in situ.
Tis(DCIS) - Intracuctal Carcinoma in situ.
Tis(LCIS) - Lobular Carcinoma in situ.
Tis(Paget's) - Paget's disease of the nipple with no tumor.
T1 - Tumor 2cm or less in its greatest dimension.
T1mic - Microinvasion 0.1cm or less in greatest dimension.
T1a - Tumor more then 0.1cm but not more than 0.5cm in its greatest dimension.
T1b - Tumor more than 0.5cm but not more than 1.0cm in its greatest dimension.
T1c - Tumor more than 1.0cm but not more than 2.0cm in its greatest dimension.
T2 - Tumor more than 2.0cm but not more than 5.0cm in its greatest dimension.
T3 - Tumor more than 5cm in its greatest dimension.
T4 - Tumor of any size with direct extension to (a) chest wall or (b) skin as described below:
T4a - Extension to chest wall.
T4b - Edema (including peau d'orange) or ulceration of the breast skin, or satellite skin nodules confined to the same breast.
T4c - Both T4a and T4b.
T4d - Inflammatory breast cancer.
Lymph Node - There are four lymph node classification values (N0, N1, N2 or N3) which depend on the number, size and location of breast cancer cell deposits in lymph nodes.
Nx - regional lymph nodes cannot be assessed. Perhaps due to previous removal.
N0 - no regional lymph node metastasis.
N1 - metastasis to movable regional axillary lymph nodes on the same side as the effected breast.
N2 - metastasis to fixed regional axillary lymph nodes, or metastasis to the internal mammary lymph nodes, on the same side as the effected breast.
N3 - metastasis to supraclavicular lymph nodes or infraclavicular lymph nodes or metastasis to the internal mammary lymph nodes with metastasis to the axillary lymph nodes.
Metastases - There are two metastatic classification values (M0 or M1) which depend on the presence or absence of breast cancer cells in locations other than the breast and lymph nodes (so-called distant metastases, e.g. to bone, brain, lung).
Originally from Wikipedia.org
Breast Cancer - Classification
Lung Cancer - Classification
The vast majority of lung cancers are carcinomas—malignancies that arise from epithelial cells. There are two main types of lung carcinoma, categorized by the size and appearance of the malignant cells seen by a histopathologist under a microscope: non-small cell (80.4%) and small-cell (16.8%) lung carcinoma.This classification, based on histological criteria, has important implications for clinical management and prognosis of the disease
Non-small cell lung carcinoma (NSCLC)
The non-small cell lung carcinomas are grouped together because their prognosis and management are similar. There are three main sub-types: squamous cell lung carcinoma, adenocarcinoma and large cell lung carcinoma.
Accounting for 31.1% of lung cancers, squamous cell lung carcinoma usually starts near a central bronchus. Cavitation and necrosis within the center of the cancer is a common finding. Well-differentiated squamous cell lung cancers often grow more slowly than other cancer types.
Adenocarcinoma accounts for 29.4% of lung cancers. It usually originates in peripheral lung tissue. Most cases of adenocarcinoma are associated with smoking. However, among people who have never smoked ("never-smokers"), adenocarcinoma is the most common form of lung cancer. A subtype of adenocarcinoma, the bronchioloalveolar carcinoma, is more common in female never-smokers, and may have different responses to treatment.
Accounting for 10.7% of lung cancers, large cell lung carcinoma is a fast-growing form that develops near the surface of the lung. It is often poorly differentiated and tends to metastasize early.
Small cell lung carcinoma (SCLC)
Small cell lung carcinoma (microscopic view of a core needle biopsy)
Small cell lung carcinoma (SCLC, also called "oat cell carcinoma") is less common.
It tends to arise in the larger airways (primary and secondary bronchi) and grows rapidly, becoming quite large.] The "oat" cell contains dense neurosecretory granules (vesicles containing neuroendocrine hormones) which give this an endocrine/paraneoplastic syndrome association. While initially more sensitive to chemotherapy, it ultimately carries a worse prognosis and is often metastatic at presentation. Small cell lung cancers are divided into Limited stage and Extensive stage disease. This type of lung cancer is strongly associated with smoking.
Metastatic cancers
The lung is a common place for metastasis from tumors in other parts of the body. These cancers are identified by the site of origin, thus a breast cancer metastasis to the lung is still known as breast cancer. They often have a characteristic round appearance on chest x-ray. Primary lung cancers themselves most commonly metastasize to the adrenal glands, liver, brain, and bone.
Staging
Lung cancer staging is an assessment of the degree of spread of the cancer from its original source. It is an important factor affecting the prognosis and potential treatment of lung cancer. Non-small cell lung carcinoma is staged from IA ("one A", best prognosis) to IV ("four", worst prognosis). Small cell lung carcinoma is classified as limited stage if it is confined to one half of the chest and within the scope of a single radiotherapy field.
Otherwise it is extensive stage.
Origenally Form :Wikipedia.org
Cancer - Classification
Nomenclature
The following closely related terms may be used to designate abnormal growths:
• Tumor: originally, it meant any abnormal swelling, lump or mass. In current English, however, the word tumor has become synonymous with neoplasm, specifically solid neoplasm. Note that some neoplasms, such as leukemia, do not form tumors.
• Neoplasm: the scientific term to describe an abnormal proliferation of genetically altered cells. Neoplasms can be benign or malignant:
o Malignant neoplasm or malignant tumor: synonymous with cancer.
o Benign neoplasm or benign tumor: a tumor (solid neoplasm) that stops growing by itself, does not invade other tissues and does not form metastases.
• Invasive tumor is another synonym of cancer. The name refers to invasion of surrounding tissues.
• Pre-malignancy, pre-cancer or non-invasive tumor: A neoplasm that is not invasive but has the potential to progress to cancer (become invasive) if left untreated. These lesions are, in order of increasing potential for cancer, atypa, dysplasia and carcinoma in situ.
The following terms can be used to describe a cancer:
• Screening: a test done on healthy people to detect tumors before they become apparent. A mammogram is a screening test.
• Diagnosis: the confirmation of the cancerous nature of a lump. This usually requires a biopsy or removal of the tumor by surgery, followed by examination by a pathologist.
• Surgical excision: the removal of a tumor by a surgeon.
o Surgical margins: the evaluation by a pathologist of the edges of the tissue removed by the surgeon to determine if the tumor was removed completely ("negative margins") or if tumor was left behind ("positive margins").
• Grade: a number (usually on a scale of 3) established by a pathologist to describe the degree of resemblance of the tumor to the surrounding benign tissue.
• Stage: a number (usually on a scale of 4) established by the oncologist to describe the degree of invasion of the body by the tumor.
• Recurrence: new tumors that appear a the site of the original tumor after surgery.
• Metastasis: new tumors that appear far from the original tumor.
• Transformation: the concept that a low-grade tumor transforms to a high-grade tumor over time. Example: Richter's transformation.
• Chemotherapy: treatment with drugs.
• Radiation therapy: treatment with radiations.
• Adjuvant therapy: treatment, either chemotherapy or radiation therapy, given after surgery to kill the remaining cancer cells.
• Prognosis: the probability of cure after the therapy. It is usually expressed as a probability of survival five years after diagnosis. Alternatively, it can be expressed as the number of years when 50% of the patients are still alive. Both numbers are derived from statistics accumulated with hundreds of similar patients to give a Kaplan-Meier curve.
Cancers are classified by the type of cell that resembles the tumor and, therefore, the tissue presumed to be the origin of the tumor. Examples of general categories include:
• Carcinoma: Malignant tumors derived from epithelial cells. This group represents the most common cancers, including the common forms of breast, prostate, lung and colon cancer.
• Sarcoma: Malignant tumors derived from connective tissue, or mesenchymal cells.
• Lymphoma and leukemia: Malignancies derived from hematopoietic (blood-forming) cells
• Germ cell tumor: Tumors derived from totipotent cells. In adults most often found in the testicle and ovary; in fetuses, babies, and young children most often found on the body midline, particularly at the tip of the tailbone; in horses most often found at the poll (base of the skull).
• Blastic tumor: A tumor (usually malignant) which resembles an immature or embryonic tissue. Many of these tumors are most common in children.
Malignant tumors (cancers) are usually named using -carcinoma, -sarcoma or -blastoma as a suffix, with the Latin or Greek word for the organ of origin as the root. For instance, a cancer of the liver is called hepatocarcinoma; a cancer of the fat cells is called liposarcoma. For common cancers, the English organ name is used. For instance, the most common type of breast cancer is called ductal carcinoma of the breast or mammary ductal carcinoma. Here, the adjective ductal refers to the appearance of the cancer under the microscope, resembling normal breast ducts.
Benign tumors are named using -oma as a suffix with the organ name as the root. For instance, a benign tumor of the smooth muscle of the uterus is called leiomyoma (the common name of this frequent tumor is fibroid). Unfortunately, some cancers also use the -oma suffix, examples being melanoma and seminoma.
Adult cancers
In the U.S. and other developed countries, cancer is presently responsible for about 25% of all deaths.[4] On a yearly basis, 0.5% of the population is diagnosed with cancer. The statistics below are for adults in the United States, and may vary substantially in other countries:
Childhood cancers
Cancer can also occur in young children and adolescents, but it is rare (about 150 cases per million yearly in the US). Statistics from the SEER program of the US NCI demonstrate that childhood cancers increased 19% between 1975 and 1990, mainly due to an increased incidence in acute leukemia. Since 1990, incidence rates have decreased.
The age of peak incidence of cancer in children occurs during the first year of life. Leukemia (usually ALL) is the most common infant malignancy (30%), followed by the central nervous system cancers and neuroblastoma. The remainder consists of Wilms' tumor, lymphomas, rhabdomyosarcoma (arising from muscle), retinoblastoma, osteosarcoma and Ewing's sarcoma. Teratoma is the most common tumor in this age group, but most teratomas are surgically removed while still benign, hence not necessarily cancer.
Female and male infants have essentially the same overall cancer incidence rates, but white infants have substantially higher cancer rates than black infants for most cancer types. Relative survival for infants is very good for neuroblastoma, Wilms' tumor and retinoblastoma, and fairly good (80%) for leukemia, but not for most other types of cancer.
Originally from Wikipedia.org
