Psoriasis - Phototherapy

Special Warning on PUVA and Skin Cancers. It has been known for some time that PUVA can modify DNA and cause genetic mutations. PUVA is known to increase the risk for squamous cell skin cancer and slightly increases the risk for basal cell skin cancer, both of which are nearly always curable. The risk for skin cancers is higher in the following patients:

Patients who have had over 200 treatments.
Patients with a family or personal history of skin cancer.
Patients with light skin and fair or red hair.
Patients who have had radiation or x-ray treatments or taken immunosuppressant drugs.

Even more worrisome was a study reporting an increased risk of melanoma, a very serious skin cancer. Discussions are under way, in fact, about discontinuing PUVA for psoriasis. The arguments generally are as follows:

Opponents of PUVA argue that studies suggest a long-term risk for melanoma, starting about 15 years after treatment, particularly in people who receive more than 250 treatments. Of note, in one 15-year study only nine out of 1,380 patients developed melanoma. However, seven of these cases occurred in the last five years of the study, indicating that the danger persists and more patients in this study are likely to develop this serious skin cancer as time goes on.
Supporters of PUVA argue that it is not yet known if the people who developed melanoma experienced sunburn during the procedures or if they already had risk factors for skin cancers. If so, then properly administered treatments could still be considered safe for patients without risk factors. They also argue that PUVA is still the most effective treatment for severe psoriasis, and the alternatives are usually very powerful and relatively new drugs that may have even more serious side effects. Furthermore, the addition of retinoids may protect against skin cancers while proving to be a very effective combination.

Protective Measures with PUVA Therapy

The side effects from UVA radiation can be severe and protective measures are needed during, before, and after treatment.

Protective Measures Before Treatment. Patients should avoid prolonged exposure to the sun for 24 hours before the oral treatment starts.

Protective Measures During Treatment. During PUVA therapy, the patient should take the following precautions:

They need to wear specially designed goggles to protect the eyes from UVA radiation.
Sensitive areas, such as genitals, abdominal skin, and breasts, are covered until tanning occurs in the exposed areas, after about a third of the treatment period. (Of note: PUVA is associated with a high risk for genital skin cancers and male genitals must be covered throughout the process.)

The following safety features should be available in the PUVA chamber:

Lamps with protective shields.
A viewing window so that a health professional can check the patient periodically.
A door that can be opened by the patient easily and with little pressure.
A timer that terminates the session automatically.
An accessible alarm device.

Protective Measures After Treatment. The drugs used in PUVA increase susceptibility for a natural sunburn for hours after treatment. The patient should take the following precautions:

Patients should wear UVA absorbing wrap-around sunglasses that are designed to completely block out stray radiation. They should begin wearing them as soon as the drug has been taken and for at least 12 hours after the treatment. This is important to prevent a PUVA reaction around the eyes that can cause cataracts. (They do not need to be taken after sundown.)
For about eight hours after taking the drug, patients must also avoid exposure to daylight, even if the day is cloudy or through windows.
Patients who must go out should wear heavy opaque clothing, including hats and gloves.
Sunblocks should be applied over all exposed areas, including the lips. The sunblock should have an SPF (sun protection factor) of more than 15 and include ingredients that block both UVB and UVA radiation.
No patient should spend any prolonged time in sunlight for at least two days after the combined treatment.