Many different cancers show increased risk after organ transplantation

November 2, 2011

ST LOUIS (MD Consult) - Organ transplant recipients are at increased risk of a wide range of cancers, including cancers unrelated to infection, reports a study in the November 2, 2011, issue of The Journal of the American Medical Association.

National, regional, and state cancer registries were used to evaluate overall patterns of cancer risk after solid organ transplantation. The linked registries provided data on 175,732 solid organ transplant recipients—about 58% received kidney transplants, 22% liver transplants, 10% heart transplants, and 4% lung transplants.

Relative and absolute risks of cancers associated with organ transplantation were assessed, compared to the general population. The analysis included the risks of 32 cancers known to be associated with infections, such as anal cancer and Kaposi sarcoma; as well as cancers with no known relationship to infections. The lead author was Dr Eric A. Engels of the National Cancer Institute.

Organ transplant recipients had an increased overall cancer risk, with an incidence of 1,375 per 100,000 person-years. The standardized incidence ratio (SIR) was 2.0, with an excess absolute risk of 719.3 per 100,000 person-years.

The most common cancers occurring at increased rates in organ transplant recipients were non-Hodgkin lymphoma, SIR 7.54; lung cancer, SIR 1.97; liver cancer, SIR 11.56; and kidney cancer, SIR 4.65. Excess absolute risks were 168.3, 85.3, 109.6, and 76.1 per 100,000 person-years, respectively.

Lung transplant recipients had the greatest increase in lung cancer risk, SIR 6.14. However, lung cancer risk was also significantly increased for other groups of transplant recipients. The increase in liver cancer risk was limited to liver recipients: SIR 43.83. This risk was extremely high in the first 6 months after liver transplantation, SIR 508.97; but much lower with long-term follow-up of 10 to 15 years, SIR 2.22.

Kidney cancer risk was increased for kidney recipients: SIR 6.66, with a bimodal pattern in onset time. Liver and heart transplant recipients were also at increased risk of kidney cancer: SIR 1.80 and 2.90, respectively.

Because of immunosuppression and oncogenic viral infections, organ transplant recipients are at increased risk of cancer. Most studies of this issue have focused on kidney transplant recipients. There are also questions about the risks of non-infection-related cancers.

The new study shows an overall increase in cancer risk after solid organ transplantation, including kidney, liver, heart, and lung recipients. Significant increases are observed for both infection and non-infection related cancers. The researchers conclude, "The elevated risk for a broad range of malignancies among transplant recipients, coupled with improvements in long-term survival, should encourage further development of approaches to prevention and early detection of cancer targeted to this population."

JAMA. 2011;306:1891-1901.