Incidence and risk factors for extra-hepatic malignancies in primary biliary cirrhosis: A comparative study from two European referral centers

Introduction: There are limited information and divergent results on the prevalence/incidence, survival, and risk factors for developing EM in PBC. Aim: To analyze the incidence/prevalence, risk factors and survival for EM in PBC patients from two European centers. Methods: The study was carried out in two series of PBC patients from two European centers (361 of Padova, Italy and 397 of Barcelona, Spain) followed-up for a mean period of 7.7±7 years and 12.2±7 years respectively. The incidence of EM was compared to the estimated incidence data from IARC (International Agency for Research on Cancer). Demographic features and factors associated with tumor development (gender, age, alcohol consumption, smoking habit, familial predisposition) were recorded. Survival analysis was compared with the expected survival predicted by the Mayo model. Results: 72 patients (35 from Padova and 37 from Barcelona) developed EM. The prevalence of cancer was similar in Padova (9.7%) and Barcelona (9.4%). The incidence of EM was also similar (855.01 vs 652.86 per 100,000 patient-year respectively, p = n.s. [95% CI −0.002 to 0.006]). The overall incidence of EM in the study population was similar to the expected incidence in the same geographical area (observed/expected ratio = 1.18 [95% CI 1.0–1.2]). Older age was the only factor associated with the development of EM. When analyzing the two series separately, familial predisposition was associated with higher likelihood of EM in Padova. Survival was similar in those with either or without EM (29.2 and 33.4 years respectively, p = n.s.). The actual survival was similar to that predicted by the Mayo model. Conclusions: The prevalence/incidence of EM is similar in Italy and Spain and is not different from the general population. Older age is the only risk factor associated with EM in PBC. The occurrence of cancer during the follow-up does not influence the natural history of liver disease.