First and subsequent nonmelanoma skin cancers: incidence and predictors in a population of New Zealand renal transplant recipients.

BACKGROUND: Renal transplant recipients (RTRs) have an increased risk of developing nonmelanoma skin cancers (NMSCs). The aims of this study were to determine the incidence and subsequent history of NMSCs in RTRs, together with risk factors.

METHODS: All patients transplanted between July 1972 and March 2007, and followed up at Christchurch Hospital, New Zealand, were studied. Immunosuppression regimens were mostly prednisone, azathioprine, cyclosporine and prednisone, mycophenolate mofetil, cyclosporine since 1998.

RESULTS: Of 384 RTRs, 96 developed at least one NMSC. The median time to first NMSC was 18.3 years (95% CI 14.2, 22.9) from transplant, as estimated by survival analysis. Individual predictors of first NMSC in RTRs were older age at first transplant (P < 0.0001), male sex (P = 0.006) and initial immunosuppression regimen (P = 0.001); only age (P < 0.0001) and male gender (P = 0.003) were significant predictors in a joint model. The mean rate of subsequent NMSCs was 1.67 per year (95% CI = 1.32, 2.11). Older age at first renal transplant (P = 0.009) or at discovery of the first NMSC (P = 0.01) was associated with a higher annual rate of new NMSC following the discovery of the first NMSC. The median survival time to a second NMSC was 2.2 years (CI 1.4, 3.0). Fourteen patients died of metastatic squamous cell carcinoma (15% case fatality).

CONCLUSIONS: NMSCs are a major health issue for RTRs, especially in older males. Once RTRs have developed their first NMSC, ongoing surveillance and prompt treatment are essential.