Are kidney transplants associated with skin cancer?

Researchers examined the potential risk between non-melanoma skin cancer (NMSC) and kidney transplant failure.

Non-melanoma skin cancer (NMSC) is a type of cancer that is classified as anything that excludes the well-known skin cancer, melanoma. In events like a kidney-related failure, NMSC is said to commonly occur in those who have received a kidney transplant.

Sexton and colleagues were interested in seeing if kidney transplants affect NMSC risk. Specifically, they looked at individuals who had kidney transplant failure and have had to face subsequent dialysis treatment. They wanted to know if individuals with kidney failure have different risks of NMSC than those who actually had a successful transplant. This study was published in JAMA Dermatology.

They took data from The Irish National Kidney Transplant Service database and the Irish National Cancer Registry between 1994 to 2014. Their analysis of the data ended on December 31, 2015.

Kidney transplant failure is associated with NMSC

A total of 3821 participants with transplants (either one, two, or three transplants) were identified from the databases. The authors’ analysis showed that a total of 39.69 per 1000 patient-years was the overall rate of NMSC. In instances where patients were on dialysis after a kidney transplant failure, the participants actually had a lower rate of NMSC.

The authors also suggested that age, being male, and transplant number were also potential risk factors associated with NMSC. Immunosuppressant drugs used to lower the likelihood of organ rejection, such as tacrolimus (relative to another immunosuppressant called cyclosporin) was shown to be potentially associated with a lower risk of NMSC.

In conclusion, between those with functioning kidney transplants and those who were on dialysis, there seemed to be a difference in the rate of NMSC. The strength of this study is that it looked at instances of dialysis as patients waited for another transplant (if receiving a second or third one), thus effectively having multiple data points for the same individual. This essentially allows for a stronger analysis.

Immunosuppressants may affect the rate of NMSC

The authors suggest that the immunosuppressants may have affected the NMSC rate even after they were not being used anymore. Also, if there were instances of longer follow-up times in the data, this may have also affected the NMSC rate between the immunosuppressive drugs mentioned earlier.

There are some limitations to this study to consider. The study type affects the ability to form definitive conclusions. In addition, there may have been more skin cancer cases than expected because clinics that specialize in kidney failure and treatment may be especially focused on checking for skin abnormalities. Other biases could have also affected these results. Regardless, this study is a valuable addition to the body of literature on this topic.

Written by Olajumoke Marissa Ologundudu B.Sc. (Hons)

Reference: Sexton DJ et al. Variation in Nonmelanoma Skin Cancer Incidence by Treatment Modality Among Patients Receiving Multiple Kidney Transplants. JAMA Dermatology. 2019; E1-E5. doi:10.1001/jamadermatol.2018.4660