A Canadian study suggested that improved strategies may be needed for cancer prevention, screening, and surveillance among solid organ transplant recipients (SOTRs).1

Researchers found that SOTRs may be at very high risk of skin cancer. They looked at 11 061 SOTRs and found that they had a significantly higher risk of cancer death compared with the general population.

“We found that transplant recipients were almost 3 times more likely to die of cancer than the general population. We found that for all types of cancer there was at least equivalent or excess mortality in transplant recipients. The excess risk of cancer mortality was highest for non-melanoma skin cancer and non-Hodgkin lymphoma,” said study author Sergio Acuna, MD, of the University of Toronto in Canada.

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However, he said these cancer types were not responsible for most cancer deaths. Non-melanoma skin cancer accounted only for 3.3% of the cancer deaths. Most cancer deaths in transplant recipients were related to lung cancer (20.9%), liver malignancy (17.7), non-Hodgkin lymphoma (15.9%), and colorectal cancer (7.1%).

The study suggested that cancer is a leading cause of death in SOTRs and the authors of this study said the cancer incidence rates are expected to increase in the next 10 years as the median age of transplant recipients increases.

“We were surprised to see the magnitude of the difference in cancer mortality. Despite the increased incidence of cancer in transplant recipients and reports of worse cancer outcomes in this population, we were expecting a smaller excess in the risk of cancer mortality given the multiple competing causes of death in this population,” said study co-author Nancy Baxter, MD, PhD, a professor in the Department of Surgery at St. Michael’s Hospital in Toronto, Canada.

“It was also quite surprising to see that the risk of cancer mortality was higher than that of the general population in older transplant recipients and that the risk of cancer death was not restricted to long-term survivors, indicating that the burden of cancer mortality was substantial even early after transplantation.”

For this investigation, Dr Baxter and colleagues examined data from patients who underwent solid organ transplantation in Ontario, Canada, between 1991 and 2010.

The analysis was conducted between November 2013 and February 2015. Mortality rates were examined by using data from the Canadian Organ Replacement Register, the Ontario Cancer Registry, and the Office of the Registrar General of Ontario death database.

The investigators identified 6516 kidney recipients, 2606 liver recipients, 929 heart recipients, and 705 lung transplantation recipients. The median age was 49 (37 to 58) years, and 36% were female (n = 4004). The study showed there were 3068 deaths and 20% (n = 603) were cancer-related.

Cancer mortality rates for SOTRs were found to be significantly elevated compared with the Ontario population with a standardized mortality ratio (SMR) of 2.84. In addition, the study showed that the risk remained elevated when patients with pre-transplant malignant neoplasms (n = 1124) were excluded (SMR: 1.93). Interestingly, the study showed that the increased risk was irrespective of transplanted organ.

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“More research is needed to understand why these differences in cancer mortality exist between transplant and non-transplant patients. Moreover, strategies for targeted cancer screening and to improve the outcomes of transplant recipients who develop cancer, specifically related to the management of immunosuppression during cancer treatment, are also needed,” Dr Acuna told Cancer Therapy Advisor.

The study showed that SOTRs were at increased risk of non-Hodgkin lymphoma mortality. However, researchers found that cardiothoracic recipients had the highest risk and there were several differences in the site-specific risk of cancer mortality.