# Soriasis--A Cancer Risk Factor?
## 4 Discussion  
Although the risk of developing certain malignancies among patients with psoriasis has been studied in several European countries, to our knowledge this is the first study conducted in Romania (Northeastern Romania). Interestingly, our results showed that the risk of CNS cancers in patients with psoriasis ranked first (RR = 15.0; 95% CI: 2.58-86.90; \(p\) = 0.001). Studies that have shown a possible association between CNS cancer and psoriasis are not very conclusive and most of them are geographically limited to Sweden and Finland [9; 10; 11; 12]. In meta-analyses [4; 5] the significant risk of developing CNS cancer among patients with psoriasis was eliminated. A similar situation as in our study was presented in a prospective U.S. cohort study from the time when methotrexate was the only systemic medication used in psoriasis [13]. Upper aerodigestive tract cancers (RR = 4.43; 95% CI: 1.43-13.75; \(p\) = 0.006) ranked second, and their association with psoriasis is known in the literature. [9; 10; 11; 12; 14; 15; 16; 17; 18]. Moreover, it is the only type of cancer for which the risk is found in both meta-analyzes [4; 5] and in our study. Only in the study by [PERSON] et al. [7] were adjustments made for the associated risk factors (alcohol and smoking), but the risk remained but was insignificant. In the first meta-analysis [4], almost half of the patients were under 50 years of age, and the follow-up period was short (4.6 years), supporting the presence of the risk of aerodigestive tract cancer risk among patients with psoriasis. Regarding the risk of thyroid cancer (RR = 2.99; 95% CI: 0.86-10.43; \(p\) = 0.076) in patients with psoriasis, the studies are contradictory. [PERSON] et al. [19] found no significant risk, and other studies reported a possible risk [20; 21]. Moreover, interesting is the reported complete resolution of psoriasis in a patient after excision of thyroid cancer [22], which could suggest common pathogenic aspects, but also new therapeutic options. The positive association of psoriasis with the risk of bladder cancer (RR = 2.99; 95% CI: 0.86-10.43; \(p\) = 0.076) in patients with psoriasis is not at all surprising, previous studies demonstrating the same thing [10; 11; 12; 13; 16; 17]. In this respect, our results are in agreement with those of the first meta-analysis [4]. However, in the study by [PERSON] et al. [7] where adjustments were made for smoking and alcohol consumption, no significant association was found between the two. As in the case of urinary tract cancer, the risk of lung cancer (RR = 2.49; 95% CI: 0.73-8.47; \(p\) = 0.136) was assessed among the population with psoriasis, sources that support this association being cited in the literature [11; 12; 13; 16]. A large cohort study of 198,366 patients with psoriasis the risk was present especially among those with moderate to severe disease. [23] On the other hand, the strong association between smoking and lung cancer is well known. Thus, the question is whether or not psoriasis is an independent risk factor for lung cancer. In two studies in which adjustment was made for smoking, the risk for lung cancer was not reported [7; 9]. The correlation of psoriasis with prostate cancer (RR = 1.43; 95% CI: 0.44-4.57; \(p\) = 0.351), although present in our study, is rarely found in the literature. This is found in a recent South Korean cohort study that included about 900,000 people [20]. The association between psoriasis and breast cancer is ambiguous (RR = 1.38; 95% CI: 0.51-3.72; \(p\) = 0.533), with previous studies reporting contradictory results [6; 8; 9; 10; 11; 12; 13; 14; 15; 20]. In a prospective study analyzing the risk of cancer among women with psoriasis aged over 65 years, the result was negative [9]. Another study on the incidence of psoriasis among women with breast cancer showed a slight increase [24]. Further studies are needed to clarify whether or not there is a relationship between psoriasis and the risk of breast cancer.