Malignancy inCrohn's disease

SUMMARY Cancer morbidity hasbeenevaluated ina series of513patients withCrohn's disease underlong-term review between 1944-76. Incomparison withmorbidity ratesforcancerinthe WestMidlands Region (the geographical areafromwhichthese patients weredrawn) the31tumours thatoccurred represented a relative risk of1.7(p<001)ofcanceratallsites. Fortumoursatsites within thedigestive systemtherelative risk was 3.3(p<0001). A significant excessoftumours was foundinboththeupper(P<0.01) andlower(P<0.001) gastrointestinal tract. Therewas no excess oftumoursatanysite outside thedigestive system. Thefirst reported caseofcancer ofthelarge intestine occurring inCrohn's disease wasdescribed by WarrenandSommers,' whileGinzburg andhis colleagues2 first drewattention tocarcinoma ofthe small intestine complicating Crohn's disease. Individual reports ofcancer inCrohn's disease havebeensummarised.3 Otherexamples ofcancer andCrohn's disease havebeendescribed elsewhere.8-11 Keighley andhiscolleagues'2 described a patient withmultifocal carcinoma ofthelarge intestine andCrohn's disease whoisincluded in thepresent series. Onlytwolong-term studies haveattempted to assess theriskofcancercomplicating Crohn's disease usingstatistical techniques.'3 '4Weedon andhiscolleagues13 identified 449patients registered attheMayoClinic between 1919and1965whose symptomsofCrohn's disease started before they were21years ofage.Eight cases ofcarcinoma of thelarge intestine wereobserved inthisselected series. Thiswas20times greater thanthenumber expected inagroupdrawnfromthegeneral populationmatched forage,sex,andyears atrisk. No excess wasobserved forcancer ofthesmall intestine. Inanearlier studyfromthisunit14 thecancer riskwasstudied in295patients withCrohn's disease ofwhom sevenhaddeveloped cancer of thedigestive tract. Although thenumberofcases ofcancerwassmall, theobserved malignancies inthegastrointestinal tract wereinexcess ofex