Hi, thanks for the D2D.
This is a great question. From published data, there may be a slight increase risk of developing cancers in Individuals with psoriasis. Some studies do show a possible increase risk of cancers like lymphoma, lung cancer and skin cancer. Possible reason for this includes the chronic inflammation and impaired immune-surveillance in psoriasis individuals.
The treatments used in psoriasis may also lead to an increase in the risk of cancers eg phototherapy can lead to increase in skin cancers and the oral and systemic treatments like cyclosporine may also increase the risk.
Overall though, the increase in cancer risks is small, so you should not be overly worried by the findings. As you have pointed out, some studies did not find significant increase risks of cancer.