Abstract
BACKGROUND: Transplant recipients have an elevated risk of cancer because of immunosuppressive medications used to prevent organ rejection, but to the authors' knowledge no study to date has comprehensively examined associations between transplantation status and mortality after a cancer diagnosis. METHODS: The authors assessed cases in the US general population (N=7,147,476) for 16 different cancer types as ascertained from 11 cancer registries. The presence of a solid organ transplant prior to diagnosis (N=11,416 cancer cases) was identified through linkage with the national transplantation registry (1987-2014). Cox models were used to examine the association between transplantation status and cancer-specific mortality, adjusting for demographic characteristics and cancer stage. RESULTS: For the majority of cancers, cancer-specific mortality was higher in transplant recipients compared with other patients with cancer. The increase was particularly pronounced for melanoma (adjusted hazard ratio [aHR], 2.59; 95% confidence interval [95% CI], 2.18-3.00) and cancers of the breast (aHR, 1.88; 95% CI, 1.61-2.19), bladder (aHR, 1.85; 95% CI, 1.58-2.17), and colorectum (aHR, 1.77; 95% CI, 1.60-1.96), but it also was increased for cancers of the oral cavity/pharynx, stomach, pancreas, kidney, and lung as well as diffuse large B-cell lymphoma (aHR range, 1.21-1.47). Associations remained significant after adjustment for first-course cancer treatment and generally were stronger among patients with local-stage cancers for whom potentially curative treatment was provided, including patients with melanoma (aHR, 3.82; 95% CI, 2.94-4.97) and cancers of the colorectum (aHR, 2.77; 95% CI, 2.07-3.70), breast (aHR, 2.08; 95% CI, 1.50-2.88), and prostate (aHR, 1.60; 95% CI, 1.12-2.29), despite the lack of an association for prostate cancer overall. CONCLUSIONS: For multiple cancer types, transplant recipients with cancer appear to have an elevated risk of dying of their cancer, even after adjustment for stage and treatment, which may be due to impaired immunity.