Multicenter analysis of immunosuppressive medications on the subsequent risk of malignancy in solid organ transplant recipients

Solid organ transplant is a curative treatment for end organ disease. However, the immunosuppressive therapy required to prevent graft rejection increases the likelihood of developing a subsequent malignancy. This retrospective cohort study from a multi-center academic hospital system investigated solid organ transplantation, immunosuppression, and the risk of subsequent malignancy. Of the 5,591 patients and 6,142 transplanted organs studied, there were 517 subsequent malignancies identified. Skin cancer was the most common type of malignancy to be diagnosed, whereas liver cancer was the first malignancy to present at a median time of one-year post-transplant. Subsequent malignancy was proportionally more often diagnosed in non-Hispanic White transplant recipients compared to other racial groups. Heart and lung transplant recipients had relatively higher rates of subsequent malignancy than liver and kidney transplant recipients, but this finding was not significant upon adjusting for immunosuppressive medications. Multivariate cox proportional hazard analysis and random forest variable importance calculations identified statistically significant correlations with sirolimus and azathioprine and high rates of malignancy after transplant, while tacrolimus was associated with low rates of post-transplant neoplasia.