by Holly A. Kerr, MD, Andrew P. Kontos, MD, and Henry W. Lim, MD
Department of Dermatology, Henry Ford Health System, Detroit, MI
UVB, UVA, UVC, PUVA -- do you feel like you're swimming in alphabet soup? Phototherapy comes in different forms, and is one of the many therapies available to treat CTCL. Beginning a new treatment can be intimidating -- what do all these terms mean? Here, we will explain the different forms of phototherapy and what you can expect. Phototherapy isn't for everyone; discuss your treatment options with your physician.
Phototherapy is the use of ultraviolet radiation, or "light," for the treatment of various skin conditions, such as mycosis fungoides (MF). It can be used either alone or in combination with other topical (creams and ointments) and/or oral medications. Ultraviolet (UV) radiation is divided into three regions: UVC, UVB, and UVA.
UVC is known as germicidal radiation and is not used for phototherapy.
Broadband UVB has been used for treatment of MF for several decades. A new form of UVB called narrowband UVB uses only a few selected UVB wavelengths. Narrowband UVB is generally more effective than broadband UVB; however, narrowband UVB phototherapy has only been available in the U.S.A. since 1997, but is gradually becoming more accessible. UVB penetrates the skin less than UVA; therefore, it is used primarily for patch stage mycosis fungoides.
UVA, or black light, is divided into UVA-1 and UVA-2. Since it has deeper skin penetration, it can be used for the treatment of thicker areas of MF. Psoralen & UVA or PUVA (pronounced pooh-vah) involves taking oral psoralen or applying topical psoralen (lotion or bath) and receiving UVA radiation from a light booth. UVA-1 is a new form of phototherapy and is not commonly available, except at academic centers. Early studies in a small number of patients show that it is equal to PUVA in early stages of MF.
Phototherapy is initially administered three times a week. It typically takes 20-30 treatments for a response to become apparent. If no response is seen at that time, an alternate light source (phototherapy) or medication should be considered. If improvement occurs with phototherapy, the frequency of treatments will be reduced and eventually discontinued.
Extracorporeal photopheresis involves removing blood with an IV needle and circulating it through a machine that filters out white blood cells, some of which are cancer cells. The white blood cells are then collected in a bag and liquid psoralen is added. The cells are exposed to UVA, which alters some of the cells and then reintroduced into the blood. This is a time consuming process and is used for those with an advanced stage of CTCL called Sezary’s syndrome (where the skin is red and there are usually a large number of abnormal cells is in the blood). Treatments are usually done on two consecutive days a month for several months to years.
Patients with mycosis fungoides must not treat themselves in tanning parlors. The light sources in tanning beds are different from those used for the medical treatment of mycosis fungoides. Each tanning bed delivers different amounts of radiation for the same amount of time and proper evaluations of the skin one would normally receive in a medical setting are not available at tanning parlors.
The side effects of phototherapy differ with each light source, but early side effects include: skin redness or sunburn, blistering, itchiness and tanning. Premature aging and wrinkling of the skin is increased with phototherapy, but is more common with PUVA than UVB. Damage to the cornea can occur with all types of phototherapy; therefore, one must follow physician’s instruction on eye protection. Cataract formation can occur if proper eye protection is not worn during and after PUVA treatment. Nausea and vomiting may occur after taking oral psoralen. Patients on PUVA must also avoid sun exposure on the days of treatment, since the medication is still present in the skin the entire day. The risk of increased skin cancer development has been documented with long-term use of PUVA (usually >250 treatments), although this has not yet been proven conclusively with UVB. Most patients will not experience side effects and can expect to carry out normal daily activities.
Depending on the stage, thickness and area of skin involvement with CTCL, your dermatologist will decide which type of phototherapy is best for your disease.