The pathophysiology underlying this increased risk of skin cancer is not entirely understood, though some evidence suggests that a major contributor is the immunosuppressant medication these patients receive for anti-rejection.

The medications themselves, especially the calcineurin inhibitors, may be toxic to cells by impairing their ability correct damaged cellular DNA. As these medications are used to reduce the body’s immune reaction to a foreign organ, they may also reduce the body’s ability to accurately survey for malignant cells — and allow established cancer cells and associated viruses to multiply without any regulation.5

The viruses most associated with post-transplant cancers include human T cell lymphotropic virus 1 (HTLV-1), Epstein-Barr virus (EBV), and Kaposi sarcoma herpes virus (KSHV), many of which have been linked in particular to skin cancer. Interestingly, some studies support the mTOR class of medications (everolimus, sirolimus) as the class of immunosuppressants associated with a lower risk of skin cancer compared with calcineurin inhibitors.6

A thorough dermatological exam prior to transplantation is vital for diagnosis as well as for documenting a detailed baseline for post-surgery reference. At the time of this exam, the patient should also complete a comprehensive family history questionnaire regarding skin cancer incidence. Patients should also be extensively counselled on performing self-skin exams monthly, with the aim of being able to identify suspicious lesions and of understanding appropriate sun protection (sunscreen, clothing, sunglasses, etc.)

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When post-transplant patients develop skin cancer, they typically present in a similar fashion to those patients without a history of solid organ transplant. Post-transplant patients may, however, have more aggressive lesions that develop more rapidly and in numerous locations.

While there are no definitive guidelines for intervals of formal dermatologic screenings with a physician, most asymptomatic patients with no history of skin cancer are typically screened every 6 to 12 months after transplant.

References

  1. Vajdic CM, van Leeuwen MT. Cancer incidence and risk factors after solid organ transplantation. Int J Cancer. 2009;125(8):1747-54. doi: 10.1002/ijc.24439
  2. Mittal A, Colegio OR. Skin cancers in organ transplant recipients. Am J Transplant. 2017;17(10):2509-30. doi: 10.1111/ajt.14382
  3. Euvrard S, Kanitakis J, Claudy A. Skin cancers after organ transplantation. N Engl J Med. 2003;348:1681-91.
  4. Garrett GL, Blanc PD, Boscardin J. Incidence of and risk factors for skin cancer in organ transplant recipients in the United States. JAMA Dermatol. 2017;153(3):296-303. doi: 10.1001/jamadermatol.2016.4920
  5. Wheless L, Jacks S, Mooneyham Potter KA, Leach BC, Cook J. Skin cancer in organ transplant recipients: more than the immune system. J Am Acad Dermatol. 2014;71(2):359-65. doi: 10.1016/j.jaad.2014.02.039
  6. Knoll GA, Kokolo MB, Mallick R. Effect of sirolimus on malignancy and survival after kidney transplantation: systematic review and meta-analysis of individual patient data. BMJ. 2014;349:g6679. doi: 10.1136/bmj.g6679