Liens entre les cancers de la peau et les Transplantations d’organes (Pour les professionnels)

Skin Cancer and Organ Transplants:  Is There A Connection? (For Professionals)

• Everyone has probably heard something about skin cancer and organ transplantation, but do these two separate entities have a connection with each other?

• To find out whether indeed, one has a possibility of getting skin cancer when one has undergone organ transplantation, let us first examine what skin cancer is.

• Skin cancer is cancer which involves the skin tissues. There are many types of skin cancer based on the cell type it involves.

1. Skin cancer that forms in melanocytes (skin cells that make pigment) is called Melanoma (Malignant Melanoma).
2. Skin cancer that forms in the lower part of the epidermis (Stratum Basale, Basal Layer)) is called Basal Cell Carcinoma (BCC) (some advocate that the cell is originated from the infundibular portion of the hair follicle epithelium).
3. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin, Stratum Spinosum, Spinous Layer)) is called Squamous Cell Carcinoma (SCC).
4. Skin cancer that forms in neuroendocrine cells (cells that release hormones in response to signals from the nervous system) is called Neuroendocrine Carcinoma of the Skin (also called Merkel Cell Carcinoma).
5. Other skin cancers stemming from other parts of the skin (epidermis, dermis and subcutaneous fat) are much rarer and will not be dealt with here.

• Chronic Sun Exposure (SCC and BCC) and Intense Short Term sun exposure are risk factors for getting skin cancerPeople with at least one severe, blistering sunburn in their lifetime are at increased risk of skin cancer.  Artificial sources of UV radiation, such as sunlamps and tanning booths, can cause skin damage and skin cancer (and are actually banned in some countries as a result). Family history is another risk factor; if you have a family member with skin cancer, you have an increased chance of getting it also. Light skin phototypes (Fitzpatrick I and II) are also at an increased risk of getting skin cancer.

• In the medical literature, some studies suggest that skin cancers are the most frequent cancers after organ transplantation. The types of skin cancers common in this group of people are Squamous Cell Carcinomas and Basal Cell Carcinomas. These types account for 95% of cancers in organ transplant recipients.

• It is said that skin cancer risk increases with time after transplantation. Squamous Cell Carcinomas and Basal Cell Carcinomas appeared to occur on sun-exposed areas 8 to 10 years after organ transplantation. The lesions appeared as keratotic, greasy, warty… lesions. These transplant-related cancers are more prevalent in the United States, Australia and Western Europe because the most important predisposing factors include fair color of the skin, eyes and hair and susceptibility to sunburn.

• These skin cancers are more aggressive in organ transplant recipient patients and Squamous Cell Carcinomas were found out to recur locally in 13.4% of patients and metastasize in 5-8% of them. However, the rate of deaths specifically related to SCC is not precisely known.

• So, why does skin cancer occur after organ transplants? One of the things most scientists are looking at is the type, duration and dosage of the immunosuppressive drugs given. Thus, we can conclude that if a person has had organ transplantation and if he or she was on immunosuppressive drugs either for a long period of time, a higher dosage or a certain type of these drugs, in addition to the already mentioned genetic and geographic factors, he or she has an increased chance of getting skin cancer. These cancers were also observed in people who received immunosuppressive drugs at ages greater than 55.

• Some of the immunosuppressive drugs we are talking about here are cyclosporine, azathioprine and sirolimus. If these three drugs are given at the same time or at higher doses, a person has an increased chance of getting skin cancer.

• A word on Azathioprine: It sensitizes cells to ultraviolet induced damage. Azathioprine reacts with the DNA in skin cells, making them give off reactive oxygen species when they are exposed to ultraviolet light.

Solutions

So, what are the solutions?

• One solution is using immunosuppressive agents in organ transplantation which carry a low risk in triggering skin cancer.  There are many clinical trials which are ongoing to discover new immunosuppressive agents which cannot predispose people to skin cancer.

• Another solution is to identify candidates for transplantation which skin cancer risk is lower. If the patient has fair color of the skin, eyes and hair, a family history of skin cancer and susceptibility to sunburn (genetic factors, photosensitivity…), then he or she has an increased chance of getting skin cancer.

• Another solution is self-examination and regular skin checks by the dermatologist which enable early detection and subsequantly an increased chance of curative treatment. If you have received organ transplantation, you should be on the watch for skin growths. The best time to do this exam is after a shower or bath. Check your skin in a room with plenty of light. You should check for:

1. any new mole (beauty spot, melanocytic nevus)
2. a change in an existing mole: a change in the size, shape, color, or feel of a mole or a sore that doesn’t heal.
3. a new red or violaceous flaky mark that may be a little raised, a new flesh-colored firm bump

• If you are a transplant patient, you should adopt lifestyle measures such as avoiding sun exposure and by wearing sun protective clothing and sunscreen (Protection index of no less than 30, sunblock better than sunscreen). You should also be more aware of your skin, so that any changes will be dealt with more sooner than later.

References:

1. Gillian M, Murphy E, Fergal. The Pathogenesis of Skin Cancer in Organ Transplant Recipients.   Vanderbilt University, Tennessee 2008. pp. 137-141

2. Clowers-Webb H, Weaver A, Otley C. Educational Outcomes Regarding Skin Cancer in Organ Transplant Recipients. American Medical Association. Arch Dermatol.Vol 142, June 2006. pp 172-174.