Why SCC is more aggressive with immunosuppression, and the immunotherapy dilemma
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Anyone can develop cutaneous squamous cell carcinoma, but people who take medication to suppress their immune system — most often solid-organ transplant recipients (kidney, liver, heart, lung), and also people on long-term immunosuppression for autoimmune disease, or with chronic lymphocytic leukemia or HIV — develop it far more often, and it behaves more aggressively once it appears.
This article explains why immunosuppression changes SCC's behavior, how surveillance and prevention are adapted for this group, and the central dilemma when advanced disease does occur: the immunotherapy drugs that work best for SCC can also trigger rejection of a transplanted organ.
Cutaneous SCC is caused by ultraviolet damage to skin cell DNA. In a healthy immune system, T cells regularly find and destroy cells that have started to turn cancerous before they grow into a tumor — a process called immune surveillance. The medications that prevent transplant rejection, and drugs used to control severe autoimmune disease, work by dampening exactly this part of the immune system.
The result, confirmed across large transplant registries, is that solid-organ transplant recipients develop SCC at roughly 65 to 100 times the rate of the general population — a bigger increase than for any other common cancer — and the excess risk climbs with the intensity and duration of immunosuppression. Thoracic organ recipients (heart, lung), who typically need stronger immunosuppression than kidney recipients, tend to have the highest risk.
Once SCC develops in this setting it also behaves differently: patients are more likely to develop multiple tumors at once or over time (sometimes dozens), tumors more often show high-risk features such as poor differentiation and perineural invasion, and rates of local recurrence, nodal metastasis, and disease-specific death are all meaningfully higher than in immunocompetent patients with an SCC of similar size.
Because the stakes are higher, care for transplant recipients and other chronically immunosuppressed patients is proactive rather than reactive:
This surveillance and prevention plan is coordinated between the transplant team and a dermatologist familiar with post-transplant skin cancer, ideally starting before symptoms of any tumor appear.
When SCC becomes locally advanced or metastatic, PD-1 immunotherapy is the standard first-line treatment for most patients — but not straightforwardly for transplant recipients. The very same PD-1/PD-L1 checkpoint that a tumor exploits to hide from the immune system is also part of what keeps a transplant recipient's immune system from attacking the donated organ.
Releasing that checkpoint to fight the cancer can also release it against the transplant. In published case series of solid-organ transplant recipients treated with checkpoint inhibitors, roughly 40% experienced acute rejection, and a substantial share of those lost the organ permanently — a return to dialysis for a kidney recipient, or a life-threatening event for a heart, lung, or liver recipient.
Because of this risk, PD-1 immunotherapy has historically been reserved for transplant recipients only when other options have been exhausted, and only after an explicit conversation about trading cancer control against the possibility of losing the transplant.
More recent, small prospective studies suggest immunotherapy does not have to be entirely off the table for kidney transplant recipients when it is approached carefully. In one such trial, 12 kidney transplant recipients with advanced SCC were treated with cemiplimab under a protocol that included preventive (prophylactic) corticosteroids and close coordination with the transplant nephrology team. Roughly 46% had a tumor response, and no case of kidney rejection or graft loss was reported during follow-up.
This kind of protocol — steroid prophylaxis, tightly monitored kidney function, and a transplant physician involved throughout — is still investigational and not yet standard care outside specialized centers, but it points toward a future where select transplant recipients with few other options can receive immunotherapy more safely. It underscores why this decision should never be made by the oncology team alone.
For most transplant recipients today, non-immunotherapy systemic options are tried first, most often cetuximab (an EGFR-targeted antibody) or platinum-based chemotherapy — covered in where chemotherapy and EGFR-targeted therapy fit — alongside surgery and radiation used as aggressively as the individual case allows.
The same elevated risk and the same immunotherapy caution apply, to varying degrees, to people on long-term immunosuppressive therapy for severe rheumatoid arthritis, lupus, inflammatory bowel disease, or other autoimmune conditions, and to people with chronic lymphocytic leukemia or other blood cancers that impair immune function, and to people with HIV whose disease is not well controlled. The details differ by condition and by which specific medications are involved, but the same principle holds: a multidisciplinary evaluation that includes whoever manages the underlying condition is essential before starting PD-1 immunotherapy.
Immunosuppression — whether from a transplant, an autoimmune condition, or another chronic illness — turns SCC from a cancer that is usually cured easily into one that occurs far more often and behaves more aggressively. Prevention and frequent skin surveillance matter more in this group than almost any other.
When advanced SCC does occur in a transplant recipient, the treatment that works best for most patients — PD-1 immunotherapy — carries a real risk of triggering organ rejection, which is why it is approached cautiously, in partnership with the transplant team, with non-immunotherapy options often tried first and newer, carefully monitored immunotherapy protocols reserved for select cases.
Disclaimer: This article is for educational purposes only and not a substitute for professional medical advice. Always consult a qualified dermatologist or oncologist about your personal diagnosis and treatment plan.
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