By KEVIN SPURGAITIS
Recipients of tissue replacements face a growing risk of developing malignant tumours, says a professor at the University of British Columbia.
“We do know that there is a definite increase of malignancy in those who had transplants,” Dr. Jason Rivers said at the Dermatology Update in Vancouver. “When you look at the skin, it is actually quite extraordinary when you think about the risk factor in getting these diseases.”
According to the skin cancer specialist, the risk of getting squamous cell carcinoma has increased 65 times among the general population — lymph by a factor of 10, basal melanoma by a factor of three and Kaposi’s sarcoma by a factor of 84. The chance of receiving carcinoma depends on where you are living. Australians experience a 45 per cent chance of getting a malignancy 10 years post transplant, compared to 35 per cent in the U.S. and 10 per cent in England.
“Fair-skinned individuals with blue or hazel eyes, who have lived in a hot climate for a number of years and had previous skin cancers, are at risk for squamous cell carcinoma.”
The duration of immunosupression needs to be considered, when examining patients for cancerous growths. The longer they have been immunosuppressed, the higher the risk of malignancy. The intensity of immunosuprression is another factor. For example, in several case studies, post-renal transplant patients with non-melanoma skin cancers run the risk of developing squamous cell and basal cell carcinoma.
Not aggressive in the general population or transplant patients, basal cell carcinoma severely affects those living with squamous cell carcinoma. Their risk for metatastic disease is an estimated seven per cent compared to the eight per cent mortality rate for those who received a transplant before 18.
Dr. Rivers said patients are not succumbing to graft failure, for example, rather from skin cancer that has metastasized to another part of the body. “We don’t generally see our patients dying of skin cancer, but they do in this situation.”
While older patients receive their malignancies primarily on the sun-exposed areas of the head and neck, younger people typically develop them on their hands and arms. However, lesions on their ears or lips have also been known to be “highly aggressive,” showing an accelerated metatastic rate.
“As dermatologists, we need to be involved with a multi-disciplinary team when dealing with transplant patients, and educate on the need for sun protection and avoidance 365 days of the year.”
In a five-year-study published in the British Journal of Dermatology in 1999, it was found that 16 renal transplant patients between 36 and 67, experienced no tumours at the outset. Half of the group remained tumour-free for five years while taking acitretin, which suggests that low doses of the drug reduces the onset of new squamous cell carcinomas. Though clinicians do not know how acitretin really works, it can be safely administered for longer periods.
While on retinoids, patients in a recent histochemical study showed an “increase in the expression of aberrant terminal differentiation.” The findings were published in the Retinoid Mechanics of Action in the Archives of Dermatology. Solid organ transplant recipients face a significantly higher risk of skin cancer, Dr. Rivers said, adding that systemic retinoids reduce the incidence of non-melanoma skin cancers.
“(Lower doses) have shown very low incidences of side effects … They should probably be used on a common basis for those patients at very high risk for developing multiple lesions,” he said.
“As dermatologists, we are going to see a lot of these patients.”
