Oncologist paper :: treating cancer

Classification of cancer determines appropriate treatment and helps determine the prognosis. Cancer develops progressively from an alteration in a cell’s genetic structure due to mutations, to cells with uncontrolled growth patterns. Classification is m e according to the site of origin, histology (or cell analysis; called grading), and the extent of the disease (called staging). Site of Origin This classification describes the type of tissue in which the cancer cells begin to develop. Here are some common examples of site of origin classification: Adenocarcinoma – originates in glandular tissue Blastoma – originates in embryonic tissue of organs Carcinoma – originates in epithelial tissue (i.e., tissue that lines organs and tubes) Leukemia – originates in tissues that form blood cells Lymphoma – originates in lymphatic tissue Myeloma – originates in bone marrow Sarcoma – originates in connective or supportive tissue (e.g., bone, cartilage, muscle) Grading Grading involves examining tumor cells that have been obtained through biopsy under a microscope. The abnormality of the cells determines the grade of the cancer. Increasing abnormality increases the grade, from 1 – 4. Cells that are well differentiated losely resemble mature, specialized cells. Cells that are undifferentiated are highly abnormal, that is, immature and primitive. Grade 1 Cells slightly abnormal and well differentiated Grade 2 Cells more abnormal and moderately differentiated Grade 3 Cells very abnormal and poorly differentiated Grade 4 Cells immature and undifferentiated Staging Staging is the classification of the extent of the disease. There are several types of staging methods. The tumor, node, metastases (TNM) system classifies cancer by tumor size (T), the degree of regional spread or node involvement (N), and distant meta asis (M). Tumor (T) T0 No evidence of tumor Tis Carcinoma in situ (limited to surface cells) T1–4 Increasing tumor size and involvement Node (N) N0 No lymph node involvement N1–4 Increasing degrees of lymph node involvement Nx Lymph node involvement cannot be assessed Metastases (M) M0 No evidence of distant metastases M1 Evidence of distant metastases A numerical system also is used to classify the extent of disease. Stage 0 Cancer in situ (limited to surface cells) Stage I Cancer limited to the tissue of origin, evidence of tumor growth Stage II Limited local spread of cancerous cells Stage III Extensive local and regional spread Stage IV Distant metastasis A doctor who specialises in treating cancer. A clinical oncologist, or radiotherapist, specialises in treating cancer with radiation, and a medical oncologist specialises in treating cancer with drugs.