No increased risk of malignancy with psoriatic arthritis

The incidence of malignancy is not increased in patients with psoriatic arthritis, according to a recent cohort analysis. "There are few current data on the baseline prevalence of malignancy in patients with psoriatic arthritis and their risk of developing cancer," the authors write. They prospectively followed 665 patients with a psoriatic arthritis from 1978 to 2004. Patients were reviewed at six to twelve-month intervals and information on the presence of malignancy was collected. The cohort was linked with a local cancer registry database to find malignancies that may have been missed or developed after patients were lost to follow-up. Overall, 68 (10.2%) patients developed a malignancy at an average age of 62.4 years. The most commonly observed malignancies were breast (20.6%), lung (13.2%), and prostate (8.8%) cancer. When compared with the rates of first malignancy in the general population the standardised incidence ratio (SIR) for all cancers was 0.98. Cancer type-specific SIRs were 0.69 and 0.88 for haematologic and lung cancer, respectively. The SIR for breast cancer was 1.55 and for prostate cancer it was 0.65. None of these ratios reached statistical significance. The investigators note that whilst there was no overall increase in cancer risk, the presence of malignancy was predicted by a high ESR and possibly a higher swollen joint count, suggesting that the 'burden of disease' is a risk for the development of cancer in patients with psoriatic arthritis. Reference...