Researchers Link Psoriasis to Increased Lymphoma Rate
First posted Nov. 21, 2003
According to a study published in the November Archives of Dermatology, psoriasis patients in a British database had a 3-fold increase in lymphoma compared to patients with no psoriasis.
The researchers, from the University of Pennsylvania, state that lymphoma is a rare form of cancer, however, with incidence rates similar to melanoma. The increased rate translates to an additional 12 cases per 10,000 people with psoriasis. They also commented that it is not clear whether the increased rate was due to psoriasis severity or treatment, or whether the results apply to younger patients.
The original data was collected from a registry of patients 65 years or older. More than 2700 patients in the database had psoriasis. After following the database of patients with and without psoriasis for a median time of 46 months, researchers found 276 lymphomas. The psoriasis patients had nearly 3 times the rate of lymphomas than the general population.
The researchers hypothesized that the increased rate may be due to the following:
- Psoriasis leads to increased T-lymphocyte activity because it is an immune mediated disease.
- Newer immunosuppressive treatments that target anti-TNF and T cells may "be an independent risk factor" for developing malignancies.
- Or, the combination of immunosuppressive treatments and the disease itself may lead to the increased rate.
The researchers recommended that the above hypotheses be tested, and that clinicians "consider the risks and benefits of long-term exposure" to medications that may induce lymphomas in psoriasis.
The U.S. Food and Drug Administration is investigating the increased rates of malignancy among rheumatoid arthritis patients using anti-TNF treatments. No conclusive research has linked malignancy from anti-TNF treatments to psoriasis and psoriatic arthritis patients.
Lymphoma includes more than 35 subtypes, consisting of 5 types of Hodgkin's lymphoma and over 30 types of non-Hodgkin's lymphoma. Over 500,000 Americans have lymphoma.
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