TORONTO, Jan. 8 (UPI) -- Solid organ transplant recipients, or SOTRs, have an increased risk of cancer, as well as a higher chance of dying from cancer, researchers in Canada found in a large review of patients.
Researchers at the University of Toronto said the increased risk of cancer and cancer death was seen regardless of the transplanted organ, though they said more research needs to be done to determine how to improve cancer treatment among transplant patients.
Researchers hypothesize transplant patients may not receive the most aggressive cancer treatment available because their immune systems have been suppressed to prevent rejection of the transplanted organ, though there is no evidence of that in their study.
"Despite the fact that SOTRs have shorter life expectancies and a higher risk of dying of non-cancer-related causes, these patients have an elevated risk of cancer death as compared with the general population," researchers wrote in the study, published in JAMA Oncology. "Addressing the cancer burden in SOTRs is critical to improving the survival of these patients."
Researchers in the study identified 11,061 patients who received an organ transplant in Ontario, Canada, between 1991 and 2010 including kidney, liver, heart, and lung transplants, and followed up over a 20-year period.
Of 3,068 deaths during the 20 years, 20 percent were related to cancer -- a number the researchers said was significantly higher when compared to the rest of the population of Ontario. The overall higher risk of cancer death existed regardless of the organ patients received. Researchers also found cancer death was higher in children after transplant, and lower in patients older than 60.
In an editorial published alongside the study in JAMA Oncology, researchers at University Medical Center Hamburg-Eppendorf in Germany and Brigham and Women's Hospital in Boston note the association between transplants and cancer death is established in the study, though an explanation for the higher instance of death remains to be shown.
"I think that we've done a really great job in getting people to live longer and live well with their transplants," Dr. Nancy Baxter, a colorectal surgeon at St. Michael's Hospital, told CBC. "It's time to shift the focus."