Do you advise patients to hold DMARDs for conditions such as psoriasis or rheumatoid arthritis while actively undergoing radiation treatment?   

Data in this setting is limited. I have usually not held DMARDs with RT unless treating with concurrent chemo RT or treating a site (pelvis) where myelosuppression caused by RT would further suppression immunity especially with biologics and methotrexate.

I recommend withholding low-dose methotrexate when giving radiotherapy to the head and neck. MTX depletes the amount of purines and pyrimidine nucleotides. These patients are often on these meds chronically and so they do not have enough nucleotides to repair DNA damage. I have seen significant muco...