Transplant recipients at increased risk for various cancer types

Engels EA. JAMA. 2011;306:1891-1901.

Organ transplant recipients are at increased risk for various types of cancers, including infection-related cancers, compared with the general population, according to researchers for the Transplant Cancer Match Study.

“The large size of the Transplant Cancer Match Study allowed us to provide accurate estimates of risk for both common and rare cancers, and for the first time, carefully document the distribution of cancers among transplant recipients,” Eric A. Engels, MD, MPH, of the National Cancer Institute, told Infectious Disease News.

For the study, the researchers pooled data on solid organ transplant recipients from the US Scientific Registry of Transplant Recipients and 13 state and regional cancer registries. From 1987 to 2008, 175,732 solid organ transplants were identified; 58.4% were kidney transplants, 21.6% liver transplants, 10% heart transplants and 4% lung transplants.

The overall risk for cancer was increased with 10,656 cases and an incidence rate of 1,375/100,000 person-years (standardized incidence ratio [SIR]=2.10; 95% CI, 2.06-2.14).

Compared with the risk among the general population, there was an increased risk for 32 different malignancies among transplant recipients — some associated with known infections (anal cancer, Kaposi’s sarcoma), others were unrelated to infections (melanoma, thyroid and lip cancers), according to the study.

The most common malignancies associated with an increased risk were: non-Hodgkin’s lymphoma (n=1,504), with an incidence of 194/100,000 person-years (SIR=7.54; 95% CI, 7.17-7.93); lung cancers (n=1,344), with an incidence of 173.4/100,000 person-years (SIR=1.97; 95% CI, 1.86-2.08); liver cancers (n=930), with an incidence of 120/100,000 person-years (SIR=11.56; 95% CI, 10.83-12.33); and cancers of the kidney (n=752), with an incidence of 97/100,000 person-years (SIR=4.65; 95% CI, 4.32- 4.99).

Specifically, lung cancer risk was highest among lung transplant recipients (SIR=6.13; 95% CI, 5.18-7.21), but also increased among kidney transplant recipients (SIR=1.46; 95% CI, 1.34-1.59), liver transplant recipients (SIR=1.95; 95% CI, 1.74-2.19) and heart transplant recipients (SIR=2.67; 95% CI, 2.4-2.95).

The risk for kidney cancer was highest among kidney transplant recipients (SIR=6.66; 95% CI, 6.12-7.23) and also increased among liver transplant recipients (SIR=1.8; 95% CI, 1.4-2.29) and heart recipients (SIR=2.9; 95% CI, 2.32-3.59). The risk for liver cancer risk was increased only among liver transplant recipients (SIR=43.83; 95% CI, 40.9-46.91).

“Cancer is an important medical complication of solid organ transplantation,” Engels said. “Further efforts are needed to develop appropriate cancer prevention, screening and treatment approaches for the transplant population.” – by Ashley DeNyse

Disclosure: During most of the period in which the study was conducted, the Scientific Registry of Transplant Recipients was managed by Arbor Research Collaborative for Health (contract HHSH234200537009C). Beginning in September 2010, the Scientific Registry of Transplant Recipients was managed by Minneapolis Medical Research Foundation (contract HHSH250201000018C).

Individuals with organ transplantation are living longer, thanks to the development of more potent anti-rejection medications. Similar to what we have seen in HIV, we can gain important glimpses into the role of immunosuppression for prolonged periods on the development of cancer in this growing population. Engels and colleagues present the largest published linked population-based cancer and transplant registries to date, representing more than 175,000 transplant recipients in the United States, providing more accurate risk assessments for less common cancers than previous reports. The report is striking for what it shows: the expected increase in risk in known virally mediated cancers in the transplant population (those associated with EBV, HBV, HCV, HHV-8, HPV and H. pylori), but a corresponding increase in risk in malignancies not thought to be mediated by infectious agents (such as lung and colorectal) hinting at the role of immunosurveillance in normally preventing malignant transformation. An important omission in the report is the impact of non-melanoma skin malignancies (squamous cell and basal cell cancers), thought to comprise 90% of all skin cancers in transplant patients. Given that skin cancers are estimated to affect more than 50% of transplant patients in their lifetime, the report is literally just skin-deep. For providers who take care of these patients in practice, this contribution to a growing literature will continue to refine how we talk to patients about risk for malignancies following transplantation. It also raises important additional questions: Is one immunosuppression regimen safer than another? When and for what malignancies should we be doing routine screening post-transplant? What is the role of recently approved vaccinations such as the prophylactic HPV vaccine in this population? How does the risk for transplant-associated malignancy change in different geographic and socioeconomic settings? Hopefully, the next generation of papers will continue to shed light on this important topic.

– Peter Chin-Hong, MD

Infectious Disease News Editorial Board member

Disclosure: Dr. Chin-Hong reports no relevant financial disclosures.

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