11/11/2011 12:05 pm ET | Updated Jan 11, 2012

Organ Transplant Patients Face Doubled Cancer Risk, Study Shows

People who have had an organ transplant have a doubled risk of developing cancer, according to a new Journal of the American Medical Association study by government health officials.

The researchers, from the National Institutes of Health and the National Cancer Institute, surveyed medical data from 175,700 people who had an organ transplant between 1987 and 2008. They found that having a transplant is linked with a higher risk of 32 kinds of cancer, including anal cancer, Kaposi sarcoma, melanoma, thyroid cancer and, most popularly, Non-Hodgkin lymphoma.

Researchers said that it's likely that at least part of the increased cancer risk comes from the immunosuppressing drugs transplant recipients have to take in order to prevent organ rejection.

And in fact, the increased risk from cancer "resembles that of people with HIV infection, whose risk is elevated for infection-related cancers due to immunosuppression," study researcher Dr. Eric A. Engels, M.D., of the NCI, said in a statement.

Researchers found that the most popular cancer developed by transplant recipients was non-Hodgkin lymphoma, which accounted for 14.1 percent of the cancers. The scientists dug further and found that this form of cancer was most common in people who had had a transplant when they were children or older adults, and the risk of this cancer was highest among people who had had a lung transplant.

The second most common cancer was lung cancer, making up 12.6 percent (risk highest among lung transplant recipients); liver cancer, making up 8.7 percent (risk highest among liver transplant recipients); and kidney cancer, making up 7.1 percent (all transplant recipients had a high risk for this cancer), according to the study.

Doctors interviewed by the San Francisco Chronicle said they weren't exactly surprised by the results of the study, but that they hoped the findings would lead to better screening recommendations for these people who have a higher cancer risk because of their transplants.

The study, doctors said, also underscores the need to refine the medications used for suppressing the immune system to allow physicians to target specific parts of the body to avoid rejection instead of weakening the entire system.

It's not secret that cancer after organ transplantation is a serious risk. Past studies have also suggested a link between the two, with the Los Angeles Times reporting just this year that heart transplant recipients have a four to 30 times increased risk of developing skin cancer.

And last year, a study in the Journal of the American Society Nephrology shows that people who have had kidney transplants have an increased risk of cancer, likely because of the immunosuppression drugs they have to take.