1. Home>
2. Specialties>
3. Dermatology>
4. Summary and Comment

Psoriasis and the Risk for Internal Malignancy: Is It Real?

Researchers find a higher risk for noncutaneous malignancy -- and a surprisingly lower risk for melanoma -- associated with psoriasis.

Psoriasis is associated with increased risk for melanoma, squamous cell carcinoma, and basal cell carcinoma. The risk for noncutaneous malignancies in patients with psoriasis remains unknown. These authors reviewed the Swedish National Cancer Registry and death records for almost 10,000 patients hospitalized with a diagnosis of psoriasis over an 18-year period. The incidences of various neoplasms in these patients were compared with incidences in the general Swedish population.

A total of 798 neoplasms were found in the study cohort, yielding an overall standard incidence ratio (SIR) of 1.37. Patients with psoriasis had a significantly increased risk for cutaneous squamous cell carcinomas (SIR, 2.46); however, they had a significantly decreased risk for melanoma (SIR, 0.32) -- an unexpected finding. Cancers of the esophagus, oral cavity, lung, and vulva and penis were significantly more common in patients with psoriasis (SIRs >2.0). The authors also found slightly increased risks for cancer of the liver, pancreas, kidney, bladder, and female breast (SIRs >1.25).

Comment: This excellent, large-scale study of the risk for cancer in patients with psoriasis produced several interesting findings. The increased risk for cutaneous and genital squamous cell carcinomas is not at all surprising and may be related, at least in part, to the therapies administered, but data on the therapies were not presented. The risk for melanoma was not increased, a very important finding that calls into question earlier findings of a relation between the two conditions. The relation between psoriasis and the increase in other neoplasms is difficult to understand. The authors suggest a possible association between smoking and drinking behaviors and other cancers that was not further examined. It is important to keep in mind that this study included only patients who had been hospitalized with psoriasis; the authors make no claim concerning associated risks for cancer in patients with psoriasis not requiring hospitalization.

— Bruce R. Smoller, MD

Published in Journal Watch Dermatology February 12, 2002

Citation(s):

Boffetta P et al. Cancer risk in a population-based cohort of patients hospitalized for psoriasis in Sweden. J Invest Dermatol 2001 Dec; 117:1531-7.

• Medline abstract (Free)