In general, any medical treatment represents some level of risk. The number one consideration is which option for treatment represents the least risk.
Phototherapy has demonstrated a history of effectiveness while proving to be quite safe. The primary question raised over the many years of phototherapy practice is whether there is an increased risk of skin melanomas. Many clinical studies have been conducted and the association has never been conclusively shown. To quote Dr. Koo, “After nearly a century of use, there is no convincing evidence that therapeutic UVB (phototherapy) increases the risk of cancers, regardless of skin type”.*
In contrast, the fine print contained in the package labeling of the biologic drug products raises serious concerns. The potential associated risks are significant and to give just a few examples include tuberculosis, listeriosis, liver failure,histoplasmosis, and other infectious diseases. Some risks are life threatening and difficult to resolve such as lymphomas (cancers that attack the lymphatic system).
* Quoted from: In the Age of Biologics Is Phototherapy Obsolete, by John Koo, M.D., Cosmetic Dermatology, Vol. 17 No. 5 S1, May 2004.