Risk factors for sebaceous carcinomas (SCs) in solid organ transplant recipients (SOTRs) in the United States were outlined in cohort study data published in JAMA Dermatology. Compared with the general population, the incidence of SC was nearly 25 times greater in SOTRs. Lung transplant and post-transplant diagnosis of cutaneous squamous cell carcinoma (SCC) were both risk factors for SC development. Patients with SC and previous transplants had decreased survival compared with patients with SC only.
Investigators conducted a retrospective cohort study using data extracted from the Transplant Cancer Match Study, which matches transplant data to cancer registry data for patients in 17 states and 1 metropolitan area in the United States. The present study used data for the years 1987 through 2017. SOTRs were followed from the date of transplantation until 1 of the following outcomes: SC diagnosis, death, transplant failure or re-transplantation, or loss to follow-up. Demographic and clinical characteristics were extracted, including data on induction and initial maintenance immunosuppressive therapies. The overall incidence of SCs in the SOTR cohort was compared with that of the general population using standardized incidence ratios (SIRs). Poisson regression was used to identify risk factors for SC. In addition, survival analyses were performed in a cohort of SOTRs and non-SOTRs with SC.
Data were analyzed from 326,282 transplant procedures performed in 301,075 patients. The distribution of patient ages was as follows: 38.8% aged 0 to44 years; 25.3% aged 45 to54 years; 25.5% aged 55 to 64 years; and 10% aged 65 years or older. The majority of patients were men (61.7%), and 62.1% were White. A total of 102 SCs were diagnosed in SOTRs during the follow-up period, corresponding to a 25-fold increased risk compared with the general population (SIR, 24.8; 95% confidence interval [CI], 20.2-30.1). Compared with other organs, lung transplantation was associated with the greatest elevation of risk vs the general population (SIR, 47.7; 95% CI, 20.6-94.0). The greatest elevation in SC risk was observed among patients who received a post-transplant diagnosis of cutaneous SCC (SIR, 104.0; 95% CI, 62.8-163.0) or basal cell carcinoma (BCC) (SIR, 63.8; 95% CI, 29.2-121.0).
In multivariate analyses, independent risk factors for SC included male sex (incidence rate ratio [IRR], 2.46; 95% CI, 1.48-4.07; P <.001), older age at transplant (IRR, 7.85; 95% CI, 3.85-16.0 for age 65 years or older vs 0-44 years; P <.001), thymoglobulin induction (IRR, 1.82; 95% CI, 1.16-2.86; P =.009), post-transplant diagnosis of cutaneous SCC (IRR, 4.60; 95% CI, 2.67-7.94; P <.001), and longer time since transplant (IRR, 8.40; 95% CI, 3.94-17.90 for10 years or more vs 0-1.9 years; P <.001). In survival analyses which compared STORs with SC (n=92) to non-SOTRs with SC (n=3585), overall survival was significantly lower in patients with previous organ transplant. In Cox proportional hazard models, previous transplant was associated with significantly elevated risk for overall mortality (hazard ratio [HR], 2.09; 95% CI, 1.45-3.01; P <.001).
These data report the incidence and overall survival of SC during a 30-year period among patients who underwent solid organ transplantation. The elevation of SC risk among SOTRs compared with non-SOTRs suggested to the researchers that immunosuppression likely plays a role in SC development. Post-transplant diagnosis of cutaneous SCC was also significantly associated with later development of SC, suggesting that ultraviolet (UV) radiation exposure may precipitate SC.
As study limitations, investigators cited the small number of SC cases in SOTRs, which prevented an analysis of cancer-specific survival. In addition, the cohort may have been too small to detect other risk factors.
“Additional studies are needed to better understand the immunologic deficits that predispose to SC and investigate the possible etiologic role of…viruses in tumor development,” investigators wrote. “[T]he elevated incidence of SC that we observed among SOTRs highlights the importance of immunosuppression in tumor development.”