Kids With Solid-Organ Transplants Also at Risk for Keratinocyte Carcinoma

By Reuters Staff

June 13, 2022

NEW YORK (Reuters Health) - Children who have received a solid organ transplant are at increased risk of keratinocyte carcinoma (KC), including squamous- and basal-cell carcinoma, new research from Canada indicates.

KC is the most common cancer after solid-organ transplant. In adult transplant patients, KC is associated with a 30- to 52-fold higher mortality rates and increased morbidity.

Dr. Cathryn Sibbald with The Hospital for Sick Children in Toronto and colleagues evaluated the incidence and risk factors for KC after pediatric solid-organ transplant.

Using an administrative health database, they identified 951 children who received a solid-organ transplant between 1991 and 2004 at a mean age of 7.8 years.

The most common organ transplanted was kidney (42%), followed by liver (30%), heart (23%) and lung (4%).

An average of 13 years after the transplant, 15 KCs were reported in 10 patients (1%). None occurred in first four post-transplant years. The average age at KC diagnosis was 25.2 years.

Eight of the 10 patients who developed KC had kidney transplantation and five died within a median follow-up of 14 years. Most kidney transplant patients with KC had a functioning graft at the time of KC diagnosis.

The incidence of KC in the organ-transplant patients was increased compared with that of the general population of children in Ontario (standardized incidence ratio, 9.09; 95% CI, 5.48 to 15.08), the study team reports in JAMA Dermatology.

The risk for KC increased with time since transplant, with adjusted hazard ratios of 3.63, 5.14 and 4.80 for one to five years, five to 10 years and 10+ years, compared with the general population.

The researchers note that prior studies of pediatric transplant patients reported primarily on internal malignant neoplasms, with limited data on KC.

"The increased risk of KC may be attributed to oncogenic viral infections, decreased host immunosurveillance, and carcinogenicity of immunosuppressants. Furthermore, the risk increases with greater duration of immunosuppression, especially relevant in kidney transplant recipients," they point out.

They caution that the incidence of KC may be underestimated owing to undiagnosed or unreported KCs. In addition, race data were only available for some of the patients and the small number of KCs precluded extensive analysis of risk factors.

Also, sun-protection practices were not captured in the database, and cumulative drug exposure associated with KC was not available.

The researchers say their data "highlight the need for further studies to confirm the risk of KC and to help support recommendations for education about sun protection and KC surveillance in this population."

SOURCE: JAMA Dermatology, online June 8, 2022.