Recently Suggested I Start Therapy Of Methotrexate To Arrest Psoriatic

Recently suggested I start therapy of Methotrexate to arrest Psoriatic arthritis and psoriasis. I have a history of Non Hodgkin's B cell lymphoma and CLL. I am on blood thinners for blood deficiency (protein C and S and factor five liden). I questioned the side effect possibility of my medical history recurring and was told that it was unlikely by doctor. 3 years I was told I was not a candidate for any medication, all conditions considered ( a different doctor). 67 years old- free from NHL and CLL treatment 14 years) What is your advice? Christine