SAN DIEGO — because of their suppressed immune systems.
“There are over 450,000 people with a solid organ transplant living in the United States. If you do the math, that works out to about 40 organ transplant recipients for every dermatologist, so there’s a lot of them out there for us to take care of,” Sean Christensen, MD, PhD, associate professor of dermatology, Yale University, New Haven, Connecticut, said at the annual meeting of the American Academy of Dermatology (AAD). “If we expand that umbrella to include all types of immunosuppression, that’s over 4 million adults in the US.”
Dr. Christensen encouraged dermatologists to be aware of the varying risks for immunosuppressive drugs and best screening practices for these patients, and to take advantage of a validated skin cancer risk assessment tool for transplant patients.
During his presentation, he highlighted five classes of immunosuppressive drugs and their associated skin cancer risks:
- Calcineurin inhibitors (tacrolimus or cyclosporine), which cause severe immune suppression and pose a severe skin cancer risk. They may also cause gingival hyperplasia and sebaceous hyperplasia.
- Antimetabolites (mycophenolate mofetil or azathioprine), which cause moderate to severe immune suppression and pose a severe skin cancer risk.
- Mammalian target of rapamycin inhibitors (sirolimus or everolimus), which cause severe immune suppression and pose a moderate skin cancer risk. They also impair wound healing.
- Corticosteroids (prednisone), which cause mild to severe immune suppression and pose a minimal skin cancer risk.
- A decoy receptor protein (belatacept), which causes severe immune suppression and poses a mild skin cancer risk.
“Most of our solid-organ transplant recipients will be on both a calcineurin inhibitor and an antimetabolite,” Dr. Christensen said. “In addition to the skin cancer risk associated with immunosuppression, there is an additive risk” that is a direct effect of these medications on the skin. “That means our transplant recipients have a severely and disproportionate increase in skin cancer,” he noted.
Up to half of solid-organ transplant recipients will develop skin cancer, Dr. Christensen said. These patients have a sixfold to 10-fold increased risk for basal cell carcinoma (BCC), a 35- to 65-fold increased risk for squamous cell carcinoma (SCC), a twofold to sevenfold increased risk for melanoma, and a 16- to 100-fold increased risk for Merkel cell carcinoma.
Transplant recipients with SCC, he said, have a twofold to threefold higher risk for metastasis (4%-8% nodal metastasis) and twofold to fivefold higher risk for death (2%-7% mortality) from SCC.
As for other kinds of immunosuppression, HIV positivity, treatment with 6-mercaptopurine or azathioprine (for inflammatory bowel disease and rheumatoid arthritis), and antitumor necrosis factor agents (for psoriasis, inflammatory bowel disease, and rheumatoid arthritis) have been linked in studies to a higher risk for nonmelanoma skin cancer.
Dr. Christensen also highlighted graft-versus-host disease (GVHD). “It does look like there is a disproportionate and increased risk of SCC of the oropharynx and of the skin in patients who have chronic GVHD. This is probably due to a combination of both the immunosuppressive medications that are required but also from chronic and ongoing inflammation in the skin.”
Chronic GVHD has been linked to a 5.3-fold increase in the risk for SCC and a twofold increase in the risk for BCC, he added.
Moreover, new medications for treating GVHD have been linked to an increased risk for SCC, including a 3.2-fold increased risk for SCC associated with ruxolitinib, a Janus kinase (JAK) 1 and JAK2 inhibitor, in a study of patients with polycythemia vera and myelofibrosis; and a case report of SCC in a patient treated with belumosudil, a rho-associated coiled-coil-containing protein kinase-2 kinase inhibitor, for chronic GVHD. Risk for SCC appears to increase based on duration of use with voriconazole, an antifungal, which, he said, is a potent photosynthesizer.
Dr. Christensen also noted the higher risk for infections in immunocompromised patients and added that these patients can develop inflammatory disease despite immunosuppression:
Staphylococcus, Streptococcus, and Dermatophytes are the most common skin pathogens in these patients. There’s a significantly increased risk for reactivation of herpes simplex, varicella-zoster viruses, and cytomegalovirus. Opportunistic and disseminated fungal infections, such as mycobacteria, Candida, histoplasma, cryptococcus, aspergillus, and mucormycosis, can also appear.
More than 80% of transplant recipients develop molluscum and verruca vulgaris/human papillomavirus infection. They may also develop noninfectious inflammatory dermatoses.