Coordinating With the Transplant Team
A key strategy to help prevent cSCC development — suggested in Dr. Bottomley’s paper, and by Dr. Arron and Dr. Christensen — is to consult with the transplant team on potentially changing a patient’s immunosuppressive medication or reducing the dose.
Dr. Arron said that a decade ago, it was somewhat of a novel concept, requiring data-sharing and making personal connections with the transplant team to forge trusting relationships. By the time she left UCSF a few years ago, she said, “the transplant program was very much on board with preventing and treating skin cancer and oftentimes they were making changes even before I would suggest them.”
Suggesting a change or dose reduction is not undertaken lightly. “Our transplant physician colleagues are balancing multiple problems in very sick patients, of which skin cancer might be one, but not the most pressing one in the setting of other transplant complications,” said Dr. Arron.
Dr. Bottomley said that “as transplant physicians, we very much respect and value the input of our dermatology colleagues,” but agreed that many factors “outside malignancy risk” must be weighed when considering changing an immunosuppressive regimen.
In a Delphi Consensus Statement on prevention of cSCC in organ transplant recipients, published in 2021 in JAMA Dermatology, the authors recommended having discussions about immunosuppression with transplant specialists, but did not make a recommendation on what strategy to use. The consensus panel said it preferred “to defer this decision to transplant physicians.”
Acitretin a Go, Nicotinamide Not So Much
Outside of changing an immunosuppressive regimen, among the interventions for secondary prevention are acitretin, the systemic retinoid, and nicotinamide, a form of niacin.
Dr. Christensen conducted a small retrospective investigation evaluating the effectiveness of acitretin in reducing cSCC in both immunocompromised and immunocompetent patients who had received care at Yale, which was recently published in the Journal of the American Academy of Dermatology. Acitretin reduced invasive cSCC by about 75% in both patient groups — a surprising result for the immunocompetent group, but well-established in patients who have had a solid organ transplant. But acitretin had no effect on cSCC in situ or basal cell carcinoma. “The benefit of acitretin is primarily in preventing the invasive SCC,” said Dr. Christensen, which is why he tends to reserve it for patients who have already had several cSCCs.
“It’s not a completely benign medication,” he said, noting the need for monitoring for cholesterol and liver function.
Several years ago, a study in immunocompetent patients, published in the New England Journal of Medicine, found that nicotinamide (also known as niacinamide) reduced the rate of nonmelonoma skin cancer by 23%, giving clinicians hope that it might also be a low-risk, low-cost cancer preventive for solid organ transplant patients. But enthusiasm has dampened since a 2023 study in the New England Journal of Medicine found that the vitamin did not reduce cSCCs in transplant recipients.
Dr. Christensen said he believes the most-recent study wasn’t powered to detect a 25% reduction in cancers. “It’s certainly possible that it still works exactly the same way in transplant patients that it does in immunocompetent patients,” he said. “There’s very little risk of recommending it to patients for general prevention. But it probably has a very modest effect in many,” he said.
Dr. Arron agreed, saying, “it may be that we simply need bigger studies to achieve that statistical significance.” Even so, she said she would not use the therapy “until there is more evidence supporting the use of nicotinamide in transplant recipients.”
Immune checkpoint inhibitors such as cemiplimab and pembrolizumab have been approved by the US Food and Drug Administration for advanced cSCC; nivolumab is another drug in the same class that has not yet been approved for cSCC. But “there’s always been a fear — and a legitimate fear — that if you gave those to organ transplant recipients they would reject their organ,” said Dr. Christensen.
Patients who take the checkpoint inhibitors may first have to stop taking their antirejection drugs, leaving them at risk. It also appears that the checkpoint inhibitors themselves contribute to organ rejection. Recent studies suggest that “the rate of organ rejection is only about 30% to 40%,” with the checkpoint inhibitors, said Dr. Christensen. “Obviously that’s still not an ideal outcome,” he said, but noted that with patients who have inoperable metastatic cSCC, “immune therapy can be a good option.”
Dr. Christensen reported no disclosures. Dr. Bottomley has previously received speaker fees and an educational grant from Astellas. Dr. Arron disclosed ties with Regeneron, Castle Biosciences, and Enspectra Health, not specific to transplantation.