No abstract

Kidney transplantation is associated with a marked increase in cancer risk at a wide variety of sites. Because SIRs for most types of cancer were not increased before transplantation, immune suppression may be responsible for the increased risk. These data suggest a broader than previously appreciated role of the interaction between the immune system and common viral infections in the etiology of cancer.

Iatrogenic immunosuppression is a unique setting for investigating immune-related mechanisms of carcinogenesis. Solid organ transplant recipients have a 3-fold excess risk of cancer relative to the age-and sex-matched general population. Population-based studies utilizing cancer registry records indicate that a wide range of cancers, mostly those with a viral etiology, occur at excess rates. To date, cancer risk has predominantly been examined in adult kidney transplant recipients in Western countries. It is yet to be established whether a similar incidence profile exists in the longterm for other solid organ, pediatric and non-Western transplant recipients. The cancer incidence profile before and after kidney transplantation strongly suggests a relatively minor contribution by both preexisting cancer risk factors and the conditions underlying end-stage kidney disease, and points to a causal role for immunosuppression. Within-cohort risk factor analyses have largely been performed on cohorts with voluntary cancer notification, and very few have incorporated biomarkers of the level of immunosuppression, the current receipt of immunosuppressive agents, or genetic risk factors. Because of their markedly high risk of certain cancers, findings from comprehensive studies in transplant recipients have the potential to raise new avenues for investigation into causal mechanisms and preventive measures against immunerelated and infectious causes of cancer. ' UICCKey words: cancer; transplantation; immunosuppression; incidence; risk; infection; kidney A wide-ranging excess risk of cancer after solid organ transplantation has been increasingly recognized over recent decades as advances in medicine have extended the life of transplant recipients. Malignancy is now a leading cause of patient death with graft function, 1-3 an outcome that can predominantly be attributed to the iatrogenic immunosuppression required to avoid rejection of the transplanted organ. Solid organ transplantation provides a unique setting for the identification of cancers under immunological control, and for examination of the risk factors for their development. Knowledge of the range of increased cancers and the magnitude of the increased risks is important in developing appropriate prevention and early detection programs for patients undergoing long-term immunosuppression. In addition, comparison of cancer incidence and risk factors between populations with different forms of immune system impairment offers insight into carcinogenic mechanisms that has ramifications for cancer control not only in these populations but also in the general community.This review focuses on the cancer incidence profile in solid organ transplant recipients, and the established and emerging risk factors for 5 cancers that occur at increased rates. Cancer incidence after solid organ transplantationShortly after the widespread introduction of solid organ transplantation, it became apparent that immune suppression was associated with a strikingly increased risk of a few canc...

In RRT, the increase in cancer is restricted, largely if not wholly, to cancers with origins in ESKD or related to immune deficiency. For the former, the cancer risk is similar in dialysis and transplantation, but for immune deficiency-related cancers, the relative risk is much greater after transplantation.