Keratinocyte Cancer Mortality in Kidney Transplant Recipients

BACKGROUND: Kidney transplant recipients are at increased risk of developing and dying from keratinocyte cancer. Risk factors for keratinocyte cancer death have not been previously described.

METHODS: In a cohort of kidney transplant recipients transplanted in Queensland 1995-2014, we identified keratinocyte cancer deaths by searching national transplant and state death registries to March 2020. Standardized keratinocyte cancer mortality rates and mortality ratios were calculated. We used a competing risks model to identify factors associated with keratinocyte cancer death and calculated relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS: There were 562 deaths in 1866 kidney transplant recipients (62% males; 86% Caucasian) with 25 934 person-years of follow-up, of which 36 were due to squamous cell carcinoma (SCC) and 1 to basal cell carcinoma (BCC) with standardized mortality rates of 78 (95% CI 53-111) and 2 (95% CI 0.1-11) per 100,000 person-years respectively. The standardized mortality ratio for keratinocyte cancer was 23 (95% CI 23-24). Besides Caucasian ethnicity (associated with 100% of keratinocyte cancer deaths), male sex (RR 3.24 95% CI 1.26-8.33), and older age at transplantation (≥ 50 versus <50 years RR 3.09 95% CI 1.38-6.89) were associated with increased risk of keratinocyte cancer death.

CONCLUSIONS: Keratinocyte cancer mortality in kidney transplant recipients is over 20 times higher than in the general population. Most keratinocyte cancer deaths are due to cutaneous SCC, however, BCC can be fatal. Education in skin cancer prevention is essential to avoid unnecessary deaths from keratinocyte cancer amongst kidney transplant recipients.