Transplant Recipients Have Higher Risk of Diverse Cancers

Eric A. Engels, MD

Patients who receive a solid organ transplant have about twice the risk of developing cancer as the general population, according to the results of a large study of US transplant recipients. In addition, the increased risk is seen for a broad range of infection-related malignancies, as well as for unrelated malignancies.

Eric A. Engels, MD, with the National Cancer Institute in Rockville, Maryland, and colleagues examined cancer risks in recipients of all organ types in 175,732 patients who had transplants from 1987 through 2008. Their data were taken from the Transplant Cancer Match Study, which is a linkage of the US solid organ transplant registry with state and regional cancer registries.

"Linkage of population-based transplant and cancer registries from the same geographic region can allow for systematic ascertainment of cancer outcomes in a large representative population of recipients,” they wrote.

Most previous linkage studies of cancer following transplantation included between 2000 and 11,000 recipients, a number that is too small to permit a precise estimate of the risk of less common cancers. In addition, studies to date have included mostly kidney recipients. Thus, the investigators said it has not been known how cancer risk varies according to the transplanted organ.

Engels and associates linked transplant recipients to 10,656 malignancy diagnoses during follow-up, which corresponded to an overall doubling of cancer risk compared to the general population, with a standardized incidence ratio (SIR) of 2.10 (95% CI, 2.06-2.14).

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Linkage of population-based transplant and cancer registries from the same geographic region can allow for systematic ascertainment of cancer outcomes in a large representative population of recipients. ”

—Eric A. Engels, MD

Risk was increased for 32 different malignancies. The SIRs were significantly increased (P <.001) for infection-related malignancies such as anal cancer and Kaposi sarcoma and non-infection-related malignancies such as melanoma, thyroid cancer, and lip cancer. Non-Hodgkin lymphoma and cancers of the lung, liver, and kidney accounted for 43% of all cancer cases in transplant recipients versus 21% of cancer cases in the US general population.

The investigators emphasized that their study offers an “overall picture” of cancer risk but cannot provide detailed analyses for individual cancers. Future studies, however, will closely examine specific cancers that “occur excessively” and their links to medical conditions and individual immunosuppressive medications.

They also pointed out that because cancer data were not available for the entire United States, they might have missed cancers if recipients moved away from their state or region after their transplant.

Engels EA, Pfeiffer RM, Fraumeni JF Jr, et al. Spectrum of cancer risk among US solid organ transplant recipients. JAMA. 2011;306(17):1891-1901.