explain how cancer spreadscommon cancerspersonal risk of cancerWHAT IS CANCER?2nd leading cause of death, following CVDabnormal, uncontrolled multiplication of cells, which if left untreated can lead to deathevery case begins as a change in a cell that allows the cell to grow and divide when it should notTumorscancers take the form of tumors, but not all tumors are cancerousbenign (non-cancerous) tumormass of normal cells enclosed in a membraneprevents penetration of other tissuespresents no danger unless it causes pressure and interferes with the fxn of other cellsmalignant (cancerous) tumorcan invade surrounding tissuescan spread via lymph nodes and blood circulationMetastasisspread of cancer cells from one part of the body to nearby tissue or different parts of the bodyoccurs because cancer cells do not stick to each other as strongly as normal cellsprimary tumor – original location of cancersecondary tumors, or metastases – new locations of tumorsmetastasizing – process of traveling and seedingStages of cancer:0 – early cancer, present only in layer of cells where it originatedI, II, III – more extensive cancer, with higher numbers indicating greater tumor size and/or degree to which cancer has spread to nearby lymph nodes or organs adjacent to primary tumorIV – advanced cancer that has spread to another organRemission – a period during the course of cancer in which there are no symptoms or other evidence of diseaseTypes of cancer:- classified according to types of cells that give rise to them- can retain some of the properties of the tissue of origincarcinomasepithelialincludes: skin, breast, uterus, prostate, lungs, GI tractmost common typesarcomasconnective, fibrous tissuesincludes: muscle, bone, cartilage, muscle and fat membraneslymphomaslymph systemleukemiasbone marrow, bloodabnormal increase in immature white blood cellsCAUSES OF CANCERRole of DNAcertain genes may predispose some people to cancerspecific genetic mutations (changes in normal makeup of gene)some are inheritedsome caused by environmental agentsradiation, viruses, chemical substances in the airwhen linked with causing cancer, know as a carcinogenTobacco usesmoking responsible for 30% of all cancer deaths, nearly 1 in 5 deaths, nearly 443,000 premature deaths a yeardirect cause of lung, bronchial, larynx, mouth, pharynx, esophagus, stomach, pancreas, kidneys, bladder, and cervixDietary factorsone of most important factors in cancer preventionexposes you to potentially dangerous compounds and deprives you of protective compoundsdietary fat and meatcolon, stomach, and prostate cancersomega-3 fats are healthier for bodyalcoholinteracts with tobacco as risk factors for oral cancerfried foodsacrylamide, probably carcinogen, found in starch-based foodsfrench fries, chips, crackersalso found in tobacco productsfruits and veggcontain essential nutrients that act as anticarcinogensvit C, vit E, selenium, carotenoids (vit A) help block cancer by acting as antioxidantsphytochemicals – substances in plants that help protect against chronic diseasesCarcinogens in the Environmentsome occur naturallyviruses, UV radiationothers are manufactured or synthethic substancesfood preservatives and additivesnitrates and nitrites found in processed meatscombine with substances in stomach and convert to nitrosamines (highly potent carcinogens)salt and smoke-cured foods linked to esophageal and stomach cancersenvironmental and industrial pollutionradon, asbestosindustrial chemicals, metals, plasticsradiationmedical x-rays, radioactive substances, UV raysfull-body CT scansCOMMON CANCERSLUNG CANCERmost common cause of cancer death160,000 deaths a yearabout 14% of all new cancer diagnosesmajor risk factor  tobacco smokeleads to 30% of all cancer deaths, 90% of lung cancer deathswhen combined with exposure to other carcinogens (asbestos, pollutants), cancer risk multiples by factor of 10+environmental tobacco smoke (ETS) – “second hand smoke”even brief exposure can cause serious harmdifficult to detect/diagnosesx: persistent cough, chest pain, recurring bronchitisvery vague, hard to pinpoint as lung cancersx do not usually appear until in later, invasive stagesonly about 15% are diagnosed in an early stagediagnosed via chest xray, CT scantreatmentdepends on the type and stage of the cancerearly stage, localized cancers can be tx with surgeryradiation and chemotherapy used in addition to surgeryphototherapy, gene therapy, immunotherapy (vaccines) being studied as hopeful future treatmentssurvival ratesif detected early, 53% of pts are alive 5 yrs post-dxoverall, 5 yr survival rate is only 16%COLON AND RECTAL CANCER3rd most common cancerrisk factorsage – 91% of cases occur after 50 yrs of ageinherited gene mutationsincreased tendency to form colon polypsmany cancers arise from preexisting polypspolyps = small growths on wall of colon that may gradually develop into malignancieschronic bowel inflammation, type II diabetesIBD (inflammatory bowel disease), Krohn’s, colitislifestyle habits – excessive alcohol, smoking, obesitydiet – rich in red meats, processed foods, simple sugarsdecreasing risk factors include:regular exercisediets rich in fruits, vegg, whole grainsresearch is mixed on benefits of high-fiber dietsoral contraceptives, hormone replacementdecrease in colorectal cancer, increase in risk of cancer in reproductive organsregular use of NSAIDs (aspirin, ibuprofen)detection/diagnosisstandard warning signs: rectal bleeding, any change in normal bowel movement (w/out any lifestyle changes)regular screening beginning around age of 50earlier for people with family hx, at high risk, or showing suggestive symptomsstool blood test – can detect small amounts of blood in stool long before obvious bleeding would be noticedmore involved screenings – sigmoidoscopy, colonoscopy – recommended at 5- or 10-yr intervalstreatmentprecancerous polyps and early-stage cancers can be removed before they become malignant or spreadsurgery is primary txradiation, chemobefore surgery to shrink tumorafter surgery to destory any remaining cancerous cells5-yr survival rates90% if detected early65% overallBREAST CANCERmost common cancer in womenlung cancer is higher in cancer death1 in 8 american women will develop it during her lifetimeabout 227,000 are diagnosed each year1 in 30 will die from diseaseabout 40,000 die from breast cancer each yearrisk factorsfemale gender – rarely occurs in mengenetic predispositionwomen