Psoriatic patients with diabetes are prone to develop digestive organ cancers: a population-based study in Taiwan

Psoriasis is an inflammatory skin condition. Epidemiology studies from different parts of the world have shown that psoriasis is associated with different components of metabolic syndrome. The association between psoriasis and development of cancer has not yet been clearly established.

We hypothesize that chronic inflammation is the driving force that enhances the risk of malignancy in psoriatic patients and suspect that psoriatic patients have higher risks for developing cancers that are most prevalent in the studied population.

Using the nested case-control approach derived from the Taiwanese population-based cohort, the current study was launched to validate this hypothesis. Results 8180 psoriatic patients and 163,600 age-matched controls were included in this study. Psoriatic patients were 1.20 folds (95% CI=1.06-1.36; p=0.004) more likely than controls to develop cancer. Further analyses revealed that incident cancers derived from digestive tract, the most common cancer origin found in Taiwanese population, were most significantly associated psoriasis. Patients with psoriasis and diabetes mellitus, a frequent comorbid condition independently associate with both psoriasis and cancer, conferred the highest risk for developing digestive tract cancers, having risks of 1.98 folds (95% CI: 1.11-3.52) and 1.68 folds (95%CI: 1.23-2.28) for the 41-60 years-old and 61-80 years-old age group, respectively. Both psoriasis and diabetes were independently associated with development of digestive tract cancers in the 41-60 years-old patient group.

Prevalent cancers in the population should be carefully monitored in the psoriatic patients after middle age (beyond 40 years of age) especially for those with concomitant diabetic conditions.