Epidemiologic critique of literature on post-transplant neoplasms in solid organ transplantation

As survival of transplant recipients improves, long-term complications become more important. We reviewed epidemiologic literature on real-world risks of de novo neoplasia post-transplant. We searched the Medline/PubMed, Cochrane, and Embase databases for population-based studies on risk of neoplasia from 1998 to 2005. Selection criteria included: solid organ transplants, neoplastic outcomes, n > 500 subjects, age >= 18 yr, and study design. Of 187 abstracts, 64 met criteria for study size, age range, topic, and design. We classified the articles by quality of reporting on components of cohort studies. Twelve of 64 studies reported cohort eligibility and exclusion criteria, defined time at risk, and ascertained incident neoplasms. Twenty-one studies reported prevalence of neoplasms for unspecified time periods, and only eight incidence studies reported person yr at risk. Three studies of all types of neoplasms in kidney recipients reported incidence ranging from 11.0 to 17.3 cases per 1000 person yr. Two studies of post-transplant lymphoproliferative disorders reported incidence of 0.4 to 2.5 cases per 1000 person yr in kidney recipients. More precise estimation of risks and rates, better description of study population, and more attention to confounding in comparisons of rates would make studies more meaningful. Reports should adhere to established guidelines for presenting methods and results in epidemiologic studies.