A new study has revealed that the overall cancer risk is two times higher for individuals who have undergone transplantation for a solid organ, such as liver, heart, lung or kidney, compared to the risk of the general public. In addition, those who have received a transplant have an increased risk for several different types of cancer. The study, carried out by researchers from the National Cancer Institute, Rockville, Md, is published in the November 2 issue of JAMA.

According to the study:

“In 2010, a total of 28,664 transplants were performed in the United States, including 16,899 kidney transplants, 6,291 liver transplants, 2,333 heart transplants, and 1,770 lung transplants.”

Individuals who receive a solid organ transplant have an increased risk of developing cancer because of immunosuppression and oncogenic viral infections.

The authors wrote:

“A better understanding of cancer risk in transplant recipients would help clarify the role of the immune system, infections, and other factors in the development of malignancy, and could identify opportunities to improve transplant safety.”

In order to assess the overall pattern of cancer after solid organ transplantation, Eric A. Engels, M.D., M.P.H., and team carried out an investigation to establish the absolute and relative cancer risk in people who had undergone transplantation compared with the general public by using linked data on recipients of transplantation from the U.S. Scientific Registry of Transplant Recipients (1987-2008) and 13 regional and state cancer registries.

By evaluating data of 175,732 transplants (39.7% of the U.S. total during 1987-2008), the researchers established that 60.9%, i.e. the majority of recipients were male and the average transplant age was 47 years, with the most commonly organs transplanted being liver (21.6%), kidney (58.4%), lung (4.0%) and heart (10.0%). During follow up, 10,656 transplant recipients were diagnosed with a malignancy, with evaluations revealing an overall doubling of cancer risk compared with that of the general public.

They discovered that recipients of transplants had an increased risk for 32 different types of malignant cancer, some related to known infections (e.g. Kaposi sarcoma and anal cancer), and others not related to infection (e.g. thyroid cancer, lip cancer and melanoma).

In addition they found that the most prevalent cancers with increased risk were non-Hodgkin lymphoma (1,504), liver cancer (930), Kidney cancer (752) and lung cancer (1,344), which collectively made up 43% of all cancer cases in individuals who had received a transplant in comparison with 21% in the U.S. general population.

Recipients of all organ types had an increased risk of non-Hodgkin lymphoma compared with the general population. Lung recipients had the greatest increased risk for lung cancer, however, the risk was also present for recipients of liver, heart and kidney organs. The risk for liver cancer was only increased among liver recipients. Kidney recipients had the greatest risk of kidney cancer, although the risk was also increased among heart and liver recipients.

The researchers explain:

“In conclusion, this large-scale registry linkage study documents a wide spectrum of cancer risk among transplant recipients. Some malignancies arise from the loss of immunologic control of oncogenic viruses, but others are unrelated to known infections. Additional contributing factors for some cancers may include other effects of chronic immune disturbance or inflammation, underlying medical conditions, or medication toxicity.

Our findings should stimulate research into carcinogenic mechanisms associated with organ transplantation. 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.”

Written by: Grace Rattue