皮肤癌Word格式文档下载.docx

皮肤癌Word格式文档下载.docx

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waxy'

material.Keratinocytesareconstantlydividingandacertainnumberaredyingatanygiventime.Thetop'

horny'

layeroftheepidermisismadeofdeadkeratinocyteswhichcontainkeratin.Thetopoftheskinisconstantlybeingshedandreplacedbynewdeadcellswhichcontainkeratin.

Melanocytes.Thesecellsaredottedaboutatthebottomoftheepidermis.Theymakeapigmentcalledmelaninwhentheskinisexposedtosun.Themelaninispassedtothenearbyskincellstoprotectthemfromthesun'

srays.Melanincausestheskintotaninfairskinnedpeople.Darkskinnedpeoplehavemoreactivemelanocytes.

Whatarecancer,skincancerandtumours?

Cancerisadiseaseofthecellsinthebody.Therearemanydifferenttypesofcellinthebody,andtherearemanydifferenttypesofcancerwhicharisefromdifferenttypesofcell.Whatalltypesofcancerhaveincommonisthatthecancercellsareabnormalandmultiply'

outofcontrol'

.

Skincancersaredividedinto:

Melanoma（'

malignantmelanoma'

）.Thistypeofskincancerdevelopsfrommelanocytes.

Non-melanoma.Thesearedividedinto:

Basalcellcarcinoma（BCC）-skincancerwhichdevelopsfrombasalcells.

Squamouscellcarcinoma（SCC）-skincancerwhichdevelopsfromkeratinocytes.

Other-othertypesofskincancerarerare.

Amalignanttumourisa'

growth'

oftissuemadeupfromcancercellswhichcontinuetomultiply.Malignanttumoursinvadeintonearbytissuesandcausedamage.Mosttypesofmalignanttumouralsotendtospread（metastasise）tootherpartsofthebody.Melanomaskincancerhasahighriskofspread.However,itisveryrareforaBCCtospread,anduncommonwithanSCC.

BasalCellCarcinoma（BCC）

Thesearethemostcommonskincancersinwhiteandfairskinnedpeople.BCCisrareindarkskinnedpeople.MostBCCsdevelopinpeopleovertheageof60.ABCCtypicallydevelopsonasunexposedareaoftheskinsuchastheheadandneck.However,theycandeveloponanyareaofskin.Thefirstsignisoftenasmallred,pinkorpearlylumpwhichappearsonpreviouslynormalskin.Thelumpisoftendomeshaped.However,BCCscanvaryinshapeandcolour.Theyusuallygrowveryslowlyandanditcantakemanymonthsforonetogrowtoacentimetreormore.

Intimethelumpontheskinmaycrustover,ulcerateorbleedfromtimetotime.AskinulcercausedbyaBCCissometimescalleda'

rodentulcer'

whichoftenlookslikeasmallinflamedcraterwitharaisededge.BCCsrarelyspread（metastasise）tootherpartsofthebody.However,untreatedtheywillcontinuetogrowlocallyandcancausedamagetonearbystructures.Forexample,aBCCmayerodeanddamagethenoseoranear.

SquamousCellCarcinoma（SCC）

Thesearethesecondmostcommonskincancerinwhiteandfairskinnedpeople.SCCisrareindarkskinnedpeople.LikeBCCs,mostSCCsdevelopinpeopleovertheageof60.AnSCCtypicallydevelopsontheface-mostcommonlyonoraroundtheearsorlips.But,again,anyareaofskincanbeaffected.Ittypicallystartsasasmallcrustedorscalyareaorskinwitharedorpinkbase.Itmaygrowintoalumpwhichmaylooklikeawart.AnSCCmayulcerateorbleedfromtimetotime.However,anearlySCCcanvaryinshape,appearanceandcolour.

AsanSCCgrowslargeranddeeper,itdamagesnearbystructures.Forexample,ifleftuntreated,anSCCnexttoanoseorearcangrowinto,erode,andthencompletelydestroythenoseorear.AnSCCmayalsospread（metastasise）tootherareasofthebody.However,thisisuncommonintheearlystagesandmostaretreatedbeforeanyspreadoccurs.

Melanoma（MalignantMelanoma）

Melanomaistheleastcommonformofskincancer,butitisthemostserious.Itistheonemostlikelytospreadtootherpartsofthebody.Melanomabecomesmorecommonwithincreasingage,butstilloccursinyoungerpeople.Melanomaisthethirdmostcommoncancerinpeopleaged15-39.Atypicalmelanomastartsasasmalldarkpatchontheskin（similartoamole）.Itcandevelopfromanormalpartofskin,orfromanexistingmole.Amelanomaisoftendifferenttoamoleinoneormoreofthefollowingways（summedupasABCD）-thatis:

Asymmetry-theshapeofamelanomaisoftenunevenandasymmetrical,unlikeamolewhichisusuallyroundandeven.

Border-theborderoredgesofamelanomaareoftenragged,notchedorblurred.Amolehasasmoothwell-definededge.

Colour-thecolour（pigmentation）ofamelanomaisoftennotuniform.Sotheremaybe2-3shadesofbrownorblack.Amoleusuallyhasoneuniformcolour.

Diameter-thesizeofamelanomaisusuallylargerthananormalmole,anditcontinuestogrow.

However,somemelanomasarenotdark,andsomemelanomasarenottypicalinhowtheylook.Asamelanomagrowsintheskinitmayitch,bleed,crustorulcerate.

Whatcausesskincancer?

Thecauseofmostskincancersissundamagetotheskin.About9in10non-melanomaskincancers,andabout6in10melanomasarethoughttobecausedbyexcessiveexposuretothesun.Inparticular,pastepisodesofsunburnsignificantlyincreasetherisk.Itistheultraviolet（UV）radiationinthesunshinewhichdoesthedamage.Skincellswhicharedamagedareatgreaterriskofbecomingabnormalandcancerous.（Seetheleafletsontheindividualcancersforotherpossibleriskfactorsandcauses.）

Althoughskincancerisrareinchildren,theamountofsunexposureduringchildhoodisthoughttoincreasetheriskofdevelopingskincancersinadultlife.Therefore,itisvitaltoprotectchildrenfromtoomuchsunshine（seebelow）.

Whatisthetreatmentandoutlookforskincancer?

Allthreemaintypesofskincancer-BCC,SCCandmelanoma-arecurableiftheyaredetectedatanearlystage.Asmallminoroperationorothermethodtoremovetheaffectedareaofskinisallthatisrequiredinearlycases.

Fornon-melanomaskincancerstheoverallcurerateisover95%,evenforoneswhichhavebeenpresentawhile.However,thelargertheygrow,themoredifficulttheyaretotreat.Moreextensivesurgeryorotherlocalisedtreatmentsmaybeneedediftheygrowlargeordeepbeforetheyaretreated.

Formelanomas,theriskofspreadtootherpartsofthebodyishigh.Thisiswhyurgentearlytreatmentisneeded.Ifithasalreadyspreadtootherareasofthebodythenthereislesschanceofacure.Treatmentssuchaschemotherapy,radiotherapyorimmunotherapyareusedformelanomaswhichhavespread.

HowcanIcheckfortheearlysignsskincancer

Trytogettoknowthesiteandlookofthenormalmolesormarksonyourbodysothatyouwillknowiftherehasbeenanychange.Ifyounoticeanynewgrowthornewchangeonyourskinandyoudonotknowwhatitisthenseeadoctor.Inparticular,ifyounoticeanychangeinthesize,shapeorcolourofanexistingmole,orifanewdarkareaofskindevelops.

HowcanIpreventskincancerfromdeveloping?

Mostskincancersarecausedbyexcessiveexposuretothesun.Weshouldalllimitoursunexposureinthesummermonths（orallyearwheninhotcountriesnearertheequator）by:

Stayingindoorsorseekingtheshadeasmuchaspossiblebetween11amand3pm.

Coveringupwithclothesandawidebrimmedhatwhenweareoutinthesunshine.

Applyingsunscreenwithasunprotectionfactorof15ormoretoallexposedareasofskinwhenweareoutinstrongsunlight.

Inparticular,childrenshouldbeprotectedfromthesun.Sunburnorexcessiveexposuretothesuninchildhoodisthoughttobethebiggestriskfactorforthedevelopingofskincancerasanadult.

Seeseparateleafletcalled'

Skincancer-Prevention'

fordetails.

Howcommonismelanoma?

Melanomaisnotcommon,butthenumberofcasesisincreasing.Thenumberofcaseshasaboutdoubledinthelast20yearsorso.Currently,about7000peopledevelopmelanomaintheUKeachyear.Itisslightlymorecommoninwomenthanmen.Manycasesoccurinolderadults.However,unlikemanytypesofcancer,alargenumberofcasesalsooccurinyoungadults.IntheUKmelanomaisthethirdmostcommoncancerinpeopleagedbetween15and40.Itisrareinchildren,butsundamageinchildrenisamajor'

riskfactor'

-seebelow.

Whatcausesmelanoma?

Acanceroustumourstartsfromoneabnormalcell.Theexactreasonwhyacellbecomescancerousisunclear.Itisthoughtthatsomethingdamagesoralterscertaingenesinthecell.Thismakesthecellabnormalandmultiply'

.（Seeseparateleafletcalled'

WhatCausesCancer'

formoredetails.）

Sundamagetoskin

Themainriskfactorwhichdamagesskinandcanleadtoamelanomaisdamagefromthesun.Itistheultraviolet（UV）radiationinthesunshinewhichdoesthedamage.About6in10casesofmelanomaarethoughttobecausedbyUVsundamage.

PeoplemostatrisktoUVskindamagearepeoplewithfairskin.Inparticularthosewithskinwhichalwaysburnsandnevertans,redorblondhair,greenorblueeyes.Melanomaisuncommonindarkskinnedpeopleastheyhavemoreprotectivemelatoninintheirskin.

Children'

sskinismostvulnerabletodamage.Sunexposureinchildhoodisthemostdamaging.Peoplewhohadalotoffrecklinginchildhood,orhadfrequentorseveresunburninchildhood,aremostatriskofdevelopingmelanomaasadults.（Thedamagetotheskincanoccurmanyyearsbeforeacanceractuallydevelops.