Photodynamic Help for Organ Transplants
Organ transplantation—the practice of transferring an organ (i.e., the heart, liver, pancreas, or kidney) from one body to another or from a donor site to another—can save lives but also pose some serious risks to the recipient. The risks stem from the fact that these patients are given drugs that suppress the immune system so that it will not attack the donated organ as a foreign invader. After the transplant, the recipient will have very low immunity and is thus quite susceptible to cancers and infections for a period of time.
The greatest risk is squamous cell carcinoma (SCC) of the skin, the second most common skin cancer worldwide. SCC occurs up to 250 times more often in organ transplant patients than in the general population. Melanoma is another major risk for these individuals, occuring six to eight times more often than in the general population. The risk is high for other life-threatening cancers, notably non-Hodgkin lymphoma and cancers of the lung, liver and kidney cancer. A recent study concluded that organ transplant recipients have a high risk of developing at least 32 different types of cancer!
Aside from avoiding excessive sun exposure, another effective way to keep SCC from occuring is to treat precancerous skin lesions, notably carcinoma in situ and actinic keratosis (also known as sun spots or age spots). These skin conditions pose a risk of developing SCC. The light-based strategy called photodynamic therapy (PDT) is among the most effective treatments because of its beneficial effects on both the condition and the immune system. Moreover it is inexpensive and easily performed in an outpatient setting, as long as the clinic or hospital has the right photodynamic equipment and medicine.
The Copenhagen Studies
Dermatology researchers at Bispebjerg Hospital in Copenhagen (Denmark) recently sought to determine how effective PDT could be for the treatment of actinic keratosis (AK) in transplant patients. The findings were reported as part of a randomized controlled trial, the gold standard for testing new medical treatments and medicines.
Over a three-year period, 25 kidney transplant recipients with clinically normal skin were randomly assigned to PDT of the face, forearm and hand. For each of the participants in this study, only half the body received the light-based treatment; the other half (contralateral side) was left untreated, thus serving as the “control” for comparison.
The researcherrs found that PDT significantly delayed onset of AK compared with untreated skin. At the three-year mark, 63% of patients showed AK lesions in untreated skin areas. By contrast, only 28% of patients had AK lesions on the PDT side of the body. Whereas there was a total number of 43 AK lesions in untreated skin, only eight AK lesions occurred in the PDT-treated skin.
The Copenhagen scientists concluded that their findings “indicate a novel approach to early prevention of skin dysplasia [i.e., creation of abnormal or precancerous cells] that may reduce morbidity from multiple AKs and SCCs in organ transplant recipients.” These findings were reported in the November 2015 American Journal of Transplantation.
A previous study by the same Danish research team attempted to assess the effects of a special laser approach (called “assisted fractional laser” or AFL), comparing this to standard daylight PDT, conventional indoor PDT, and AFL alone in treating organ transplant recipients. The purpose of the study was to see which approach was most effective against difficult-to-treat AK lesions.
In each patient, four areas in the same body region were randomly assigned to receive to one of each treatment. The PDT used methyl aminolaevulinate as the photosensitizing cream, applied to the treatment area before light exposure. The findings clearly showed that the special laser-assisted approach combined with daylight PDT resulted in complete remissions with excellent tolerability compared with the other PDT strategies, as reported in the February 2015 British Journal of Dermatology.
Each year, the number of organ transplant patients is steadily increasing each year, as is their life expectancy. For this reason, it is essential to explore ways to prevent SCC and other common cancer-related risks, and to look for ways to better manage such risks. PDT offers great possibilities for both prevention and treatment of SCC. Of course, catching cancer at an early stage is where PDT can have its greatest impact, and this applies to many of the cancers that could arise following an organ transplant.
Sources
Togsverd-Bo K, Lei U, Erlendsson AM, Taudorf EH, Philipsen PA, Wulf HC, Skov L, Hædersdal M. Combination of ablative fractional laser and daylight-mediated photodynamic therapy for actinic keratosis in organ transplant recipients – a randomized controlled trial. Br J Dermatol. 2015 Feb;172(2):467-74.
Hayashi N, Kataoka H, Yano S, Tanaka M, Moriwaki K, Akashi H, Suzuki S, Mori Y, Kubota E, Tanida S, Takahashi S, Joh T. A novel photodynamic therapy targeting cancer cells and tumor-associated macrophages. Mol Cancer Ther. 2015 Feb;14(2):452-60
Gordon Spratt EA, Carucci JA. Skin cancer in immunosuppressed patients. Facial Plast Surg. 2013 Oct;29(5):402-10.
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