I have psoriasis and PSA which is fully in remission.
I took low dose methotrexate before melanoma, which was 1a or insitu, depending on which pathologist you choose to believe.
I also have a narrow band UVB light box which I use once a week, before melanoma I used it twice a week. I have been able to scale the treatment down with no impact on the control of my psoriasis.
After consulting with a Stanford dermatologist and one at UCSF, I am convinced these treatments did not cause the melanoma. My dermatologist concurs, and I have continued the treatment post my one experience with melanoma, which was five years ago.
In my experience, some doctor’s overreact and say you should not use methotrexate, light or biologics to treat your psoriasis and PSA, if you have had melanoma.
However, they are also serious diseases and can cause severe damage and ruin your quality of life. Educate yourself and make your own decision, I consulted doctors outside my main insurance because I was concerned they might limit my treatment no matter what my decision.
Your decision depends on a lot of things the severity of your melanoma, psoriasis and PSA, If you have control over the psoriasis and PSA. I personally have chosen to continue to treat without too much concern that these treatments cause melanoma. Most studies on narrow band UVB and methotrexate indicate they do not increase your risk. Read, educate yourself, consult outside experts and make your own treatment decision.
My dermatologists were much more helpful than my rheumatologist.
I hope this helps.