Study Strengthens Evidence of Link Between Liver Cancer and Diabetes

SEATTLE-Diabetics may facethree times the risk of liver cancer,according to data from a new study. Anumber of epidemiological studieshave "suggested a relationship betweensome cancer types and diabetes, andthe most consistent results have beenfor cancers of the liver and the pancreas,"said Marie-Claude Rousseau, PhD,a postdoctoral fellow, in the Departmentof Social and Preventive Medicine,at the University of MontrealFaculty of Medicine."Some biological mechanisms havebeen proposed to suggest how diabetesaffects the risk of cancer, but to thisday, they remain only hypothetical. Soclearly, the question of whether cancerrisk is associated with diabetes isstill open," Dr. Rousseau said. Shepresented the findings at the AmericanAssociation for Cancer ResearchThird Annual International Conferenceon Frontiers in Cancer PreventionResearch (abstract 195).The investigators used data collectedfrom a study conducted in Montreal during the 1980s designed to addressworkplace factors and the risk ofcancer among men. The large population-based multisite case-controlstudy included information about priordiagnosis for diabetes, age at diagnosis,and medication use for diabetes.The study sample was comprisedof 3,288 male patients who had beenrecently diagnosed with cancer and509 healthy controls.Patients with diabetes also providedinformation about their usualheight and weight and lifestyle factors."These are important to consider whenstudying diabetes and cancer risk,"Dr. Rousseau said.The investigative team analyzed theassociation between diabetes and 12different types of cancer. "Out of the20 different cancer types that weredocumented in this study, our analysesfocused on 12 types for which thenumber of patients was large enoughto provide sufficient statistical powerfor the analyses," she explained.Study ResultsAfter adjusting for body mass indexand other covariates, the risk ofliver cancer was found to be elevatedamong men who reported a prior diagnosisof diabetes. The adjusted oddsratio (OR) was 3.1. The proportion ofdiabetics was 24% among liver cancerpatients, while only 8% of controlsreported having diabetes."These estimates were slightly higherwhen we used a more stringent definitionof diabetes," Dr. Rousseau said.This definition included only thosesubjects who were taking medication.The adjusted odds ratio for liver cancerfor this subgroup was 3.9.An association was observed withpancreatic cancer, mostly due to recentlydiagnosed diabetes. "This maysuggest that diabetes was a result of thepancreatic cancer rather than the opposite,"Dr. Rousseau said.The researchers did not observe anyassociation with other cancers studied,including melanoma, non-Hodgkin's lymphoma, and cancers ofthe esophagus, stomach, colon,rectum, lung, prostate, bladder, andkidney."While this was not the first studyto examine the link between cancerand diabetes, key features of our studieswere that we could assess the risk ofseveral different cancer types in thesame population and that the patientswere newly diagnosed," Dr. Rousseausaid. "Also, we had information thatallowed us to adjust for important factors,such as body mass index, smoking,and alcohol consumption. In conclusion,our study is strengthening theevidence of a link between diabetesand liver cancer."Dr. Rousseau's colleagues in thestudy were Jack Siemiatycki, PhD, Universityof Montreal, and Marie-EliseParent, PhD, INRS-Institut Armand-Frappier, Laval, Quebec.