# Soriasis--A Cancer Risk Factor?
## 4 Discussion
The risk of colorectal cancer (RR = 1.25; 95% CI: 0.52-2.98; \(p\) = 0.242) is not new, being frequently associated with inflammatory diseases [9; 14; 16; 25]. This risk was also high in the most recent meta-analysis [5]. A study of Iowa women that included over 32,000 women [9] found a significant association between psoriasis and colorectal cancer, especially proximal colorectal cancer. An argument in favor of the fact that inflammation has a role in colorectal tumorigenesis could be the proven protective effect of an antiinflammatory drug--aspirin [26]. In addition, the correlation of increased C-reactive protein (CRP) level with colorectal cancer risk has been reported [27]. The risk of cervical cancer in people with systemic inflammatory diseases such as inflammatory bowel disease, rheumatoid arthritis, and lupus erythematosus has been documented [28; 29; 30; 31]. The psoriasis-cervical cancer association is not supported by the literature data [12; 13; 32; 33]. Possibly due to the insufficient number of cases, we failed to investigate the association between psoriasis and other cancers cited in the literature, such as NMSCs [10; 17; 33; 34; 35; 36], lymphomas [7; 20], pancreas [19], liver and genital cancers [19; 20]. Although our study did not identify a risk for lymphohematopoietic cancers, previous studies have reported a risk for their development in patients with psoriasis [6; 20; 37; 38; 39; 40]. Additionally, in a retrospective cohort study that included biologic-naive children with psoriasis and a control group of children without psoriasis, a risk for developing lymphoma was found only in the former [41]. Surprisingly, in our study no correlation was found between NMSC and psoriasis. One possible explanation is that the wide range of systemic medications and effective biologic therapy currently available have significantly reduced the use of 8-methoxy-poralen-ultraviolet-A (PUVA), especially since the study is relatively recent. Previous studies have shown a linear increase in the risk of NMSC with the number of PUVA sessions [21; 34]. A systematic review of 46 studies has identified that squamous cell carcinoma (SCC) can develop following relatively low exposure to UVA, and the risk increases linearly with the number of treatments [42]. Worryingly, the increased risk of SCC persists after discontinuation of PUVA therapy. Despite the increased risk of NMSC in patients with psoriasis, there is little evidence that such skin cancers are either more aggressive or associated with increased mortality [43]. Regarding the risk of developing melanoma, our results are in agreement with the meta-analyzes, only one such patient in the psoriasis group being recorded. Previous studies have contradictory results [7; 15; 16; 17; 33; 44; 45; 46]. In addition, a retrospective Italian study including 72,739 patients showed a low frequency of melanoma among the psoriasis patients attributed to the network of proinflammatory cytokines that would have a protective role against melanoma [47]. The role of various classes of drugs used in the treatment of psoriasis (biological therapy included) in carcinogenesis has been under scrutiny. They inhibit inflammation by suppressing the activity and proliferation of immune cells and the production of cytokines involved in innate and adaptive immune responses. A meta-analysis conducted in that respect [48] indicates an increased risk of lymphoma, but it could not specify whether it is due to the disease itself, the immunosuppressive effect of the medication, or both. Thus, in patients with severe disease and multiple comorbidities, the choice of immunomodotherapy therapies may be confusing due to the increased risk of cancer. On the other hand, early and effective control by immunosuppressive therapies significantly reduces inflammation which in its turn is an independent risk factor for tumorigenesis. Of the immunosuppressive therapies, we mention Cyclosporine and Methotrexate.