February 10, 2014

Cancer-Basics

     Cancer is a class of diseases characterized by out-of-control cell growth called tumours (except in the case of leukemia). Tumours can grow and interfere with the  digestive, nervous, and circulatory systems and they can release hormones that alter body function. Tumours that stay in one spot and demonstrate limited growth are generally considered to be benign.Malignant tumours are formed when cancerous cell destroys healthy tissue in body (invasion) or when they divide and grow, making new blood vessels to feed itself (angiogenesis).

Cause

     Cancer is the result of uncontrollable cell growth. Normal cells in the body follow an orderly path of growth, division, and death. Unlike regular cells, cancer cells do not experience programmatic death and instead continue to grow and divide. This leads to a mass of abnormal cells that grows out of control. 
  • Carcinogens, a groupof substances are directly responsible for damaging DNA, promoting or aiding cancer. Tobacco,    asbestos, arsenic, radiation such as gamma and x-rays, the sun, and compounds in car exhaust fumes are all examples  of carcinogens. When our bodies are exposed to carcinogens, free radicals are formed that damage cells and affect their ability to function normally.
  • Cancer can also be the result of a genetic predisposition that is inherited from family members. It is possible to be bornwith certain genetic mutations or a fault in a gene that makes one statistically more likely to develop cancer later in life.
  • Age also increases the number of possible cancer-causing mutations in our DNA. This makes age an important risk factor for cancer. 
  • Several viruses have also been linked to cancer such as: human papillomavirus (a cause of cervical cancer), hepatitis B  and C (causes of liver cancer), and Epstein-Barr virus (a cause of some childhood cancers). Human immunodeficiency  virus (HIV) - and anything else that suppresses or weakens the immune system - inhibits the body's ability to fight infections and increases the chance of developing cancer.


Symptoms
  • Occurrence of an unusual lump in the body
  • Variations in a mole on the skin
  • Persistent cough or hoarseness
  • Change in bowel habits, such as unusual diarrhoea or constipation
  • Difficulty in swallowing or persistent indigestion
  • Abnormal bleeding including bleeding from the vagina or blood in urine or faeces
  • Persistent sore or ulcer
  • Difficulty passing urine
  • Unexplained weight loss
  • Unexplained pain
  • Tiredness or fatigue
  • Skin changes such as an unexplained rash or unusual texture
  • Unexplained night sweats
Diagnosis
     Early detection of cancer can greatly increase the odds of successful treatment and survival. Physicians use information from symptoms and several other procedures to diagnose cancer.The treatment is based on certain characteristics such as, the type of cancer, the stage of the cancer, age, health status, and additional personal characteristics. Treatments usually fall into one of the following categories: surgery, radiation, chemotherapy, immunotherapy, hormone therapy, or gene therapy.
  • Surgery is the oldest known treatment for cancer. It is possible to completely cure a patient by surgically removing the cancer from the body. This is often seen in the removal of the prostate or a breast or testicle. If the disease has spread,then it is nearly impossible to remove all of the cancer cells.
  • Radiation treatment destroys cancer by focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to commit suicide. Radiotherapy utilizes high-energy gamma- rays that are emitted from metals such as radium or high-energy x-rays that are created  in a special machine.
  • Chemotherapy utilizes chemicals that interfere with the cell division process - damaging proteins or DNA - so that cancer cells will commit suicide. These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage while cancer cells cannot.Common side effects such as hair loss, nausea, fatigue, and vomiting are observed.
  • Immunotherapy aims to get the body's immune system to fight the tumour. Local immunotherapy injects a treatment into an affected area, for example, to cause  inflammation that causes a tumour to shrink. Systemic immunotherapy treats the whole body by administering an agent  such as the protein interferon alpha that can shrink tumours.
  • Hormone therapy is designed to alter hormone production in the body so that cancer cells stop growing or are killed completely. Several cancers have been linked to some types of hormones, most notably breast and prostate cancer.Breast cancer hormone therapies often focus on reducing estrogen levels (a common drug for this is tamoxifen) and  prostate cancer hormone therapies often focus on reducing testosterone levels.
  • The goal of gene therapy is to replace damaged genes with ones that work to address a root cause of cancer: damage toDNA.Other gene-based therapies focus on further damaging cancer cell DNA to the point where the cell commits suicide.Gene therapy is a very young field and has not yet resulted in any .

Source

              medicalnewstoday ,  
              webmd , 
              Picture

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