Patient Population
After approval from the Johns Hopkins Institutional Review Board, we queried the Organ Procurement and Transplantation Network (OPTN) database for all adult (>18 years) heart transplant patients between October 1987 through September 2018. All data is deidentified (no informed consent). We excluded multi-organ transplant recipients, those without malignancy data (i.e. no post-transplant malignancy entry to correspond to transplant entry), and those with less than six months of follow-up. Among patients we identified who developed a post-transplant malignancy, we excluded a recurrence of a pre-transplant malignancy, squamous cell carcinoma, and basal cell carcinoma.