Cancer• Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems. • Cancer harms the body when damaged cells divide uncontrollably• Cancer is a class of to form lumps or masses of tissue diseases characterized called tumors . by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially
Not all tumors are cancerous;tumors can be:a. BenignBenign tumors arent cancerous. They can oftenbe removed, and, in most cases, they do notcome back. Cells in benign tumors do not spreadto other parts of the body.b. MalignantMalignant tumors are cancerous. Cells inthese tumors can invade nearby tissuesand spread to other parts of the body. Thespread of cancer from one part of the bodyto another is called metastasis.
What causes cancer?Cancer is ultimately the result of cells thatuncontrollably grow and do not die. Normalcells in the body follow an orderly path ofgrowth, division, and death. Programmedcell death is called apoptosis, and whenthis process breaks down, cancer beginsto form. Unlike regular cells, cancer cellsdo not experience programmatic deathand instead continue to grow and divide.This leads to a mass of abnormal cells thatgrows out of control.
• Genes- the DNA typeCells can experience uncontrolled growthif there are damages or mutations toDNA, and therefore, damage to the genesinvolved in cell division. Four key types ofgene are responsible for thecell division process: oncogenes tell cellswhen to divide, tumor suppressor genestell cells when not to divide, suicide genescontrol apoptosis and tell the cell to killitself if something goes wrong, and DNA-repair genes instruct a cell to repairdamaged DNA.
• CarcinogensCarcinogens are a class of substancesthat are directly responsible for damagingDNA, promoting or aiding cancer.Tobacco, asbestos, arsenic, radiation suchas gamma and x-rays, the sun, andcompounds in car exhaust fumes are allexamples of carcinogens. When ourbodies are exposed to carcinogens, freeradicals are formed that try to stealelectrons from other molecules in thebody. Theses free radicals damage cellsand affect their ability to function normally.
• Genes- family typeCancer can be the result of a geneticpredisposition that is inherited fromfamily members. It is possible to beborn with certain genetic mutations or afault in a gene that makes onestatistically more likely to developcancer later in life.
• Other medical factorsAs we age, there is an increase in the number ofpossible cancer-causing mutations in our DNA.This makes age an important risk factor for cancer.Several viruses have also been linked to cancersuch as:a. human papillomavirus (a cause of cervical cancer)b. hepatitis B and C (causes of liver cancer)c. Epstein-Barr virus (a cause of some childhood cancers).d. Human immunodeficiency virus (HIV) - and anything else that suppresses or weakens the immune system - inhibits the bodys ability to fight infections and increases the chance of developing cancer.
• How is cancer diagnosed and staged?Early detection of cancer can greatlyimprove the odds of successful treatmentand survival. Physicians use informationfrom symptoms and several otherprocedures to diagnose cancer. Imagingtechniques such as X-rays, CT scans, MRIscans, PET scans, and ultrasound scansare used regularly in order to detect wherea tumor is located and what organs maybe affected by it. Doctors may alsoconduct an endoscopy, which is aprocedure that uses a thin tube with acamera and light at one end, to look forabnormalities inside the body.
How can cancer beprevented?A persons cancer risk can be reducedin other ways by receiving regularmedical care, avoiding tobacco, limitingalcohol use, avoiding excessiveexposure to ultraviolet rays from the sunand tanning beds, eating a diet rich infruits and vegetables, maintaining ahealthy weight, and being physicallyactive.
Effective Cancer PreventionMeasuresOpportunities exist to reduce cancer risk and preventsome cancers. Cancer risk can be reduced by avoidingtobacco, limiting alcohol use, limiting exposure toultraviolet rays from the sun and tanning beds, eating adiet rich in fruits and vegetables, maintaining a healthyweight, being physically active, and seeking regularmedical care. Research shows that screening for cervicaland colorectal cancer at recommended intervals canprevent these diseases by finding lesions that can betreated before they become cancerous. Screening alsocan help find cervical, colorectal, and breast cancers at anearly, treatable stage. Vaccines also can reduce cancerrisk. The human papillomavirus (HPV) vaccine helpsprevent some cervical, vaginal, and vulvar cancers. Thehepatitis B vaccine can reduce liver cancer risk. Makingcancer screening, information, and referral servicesavailable and accessible to all Americans can reducecancer incidence and deaths.
• Primary preventionPrimary prevention, which aims toreduce or eliminate exposure to cancer-causing risk factors, will be critical forcontrolling cancers in developingcountries. The most importantprevention measures are the following:
Immunization against or treatment ofinfectiousagents associated with cancers.*Two vaccines are particularlyimportant: a human papilloma virus(HPV) vaccine to prevent infection fromcertain types of the virus that can leadto cervical cancer, and Hepatitis B tohelp prevent liver cancer. The HPVvaccine can potentially prevent about70 percent of cervical cancer cases.
National tobacco and alcohol control programs. * Tobacco use is the most important causeofcancers of the lung and respiratory system andtheesophagus, and it contributes to several othercancers.Excessive alcohol consumption accounts for 20percent to 30 percent of liver and esophagealcancers.Effective tobacco and alcohol control programsinclude increasing taxes on theproducts, restrictingor banning advertising and promotion, banningsmoking in public places, educating the publicaboutthe health risks of excessive use, and making
Programs to promote diets thatinclude more fruits and vegetablesand fewer harmful fats andprocessed foods.*Promoting healthy diets and exercisecan take place in schools and worksites and through other public healthcampaigns. Promoting healthy lifestylesand curbing obesity can reduce the riskof cancer as well as the risk of manyother (particularly cardiovascular)diseases.
• Secondary preventionEarly Detection of Cancer *The main objective of making cancer screeningwidelyavailable is to detect cancer cases early enough to makecurative treatment possible. Screening for liver, stomach,lung, and colorectal cancers have focused on people athigherrisk for those cancers (for example, people over age 50andsmokers), but the value of early detection varies greatlywiththe type of cancer. For example, screening for livercancercan result in earlier diagnosis, but because treatment ofthatcancer is largely ineffective, screening has not been
Cancer prevention is an essentialcomponent of all cancercontrol plans because about 40% of allcancer deaths canbe prevented.
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