PDT has been used in cancers to lengthen survival and improve quality of life. Although PDT is effective and causes no long-term problems, it is not widely used to treat cancer today. Still, it is offered in certain treatment centers. PDT is being studied in many clinical trials, and it is becoming more widely recognized as a valuable treatment option for localized cancers. Three photosensitizing agents are currently approved by the United States Food and Drug Administration (FDA) to treat certain cancers or precancerous conditions:

Porfimer sodium (Photofrin^®)

Porfimer sodium is the most widely used and studied photosensitizer. It is activated by red light from a laser to treat patients with:

• cancer of the esophagus (the swallowing tube)

• to relieve symptoms that are caused by a tumor totally blocking the esophagus

• to relieve symptoms that are caused by a tumor that partly blocks the esophagus and can't be treated with laser therapy

• Barrett esophagus, a condition that may lead to esophageal cancer in patients who don't have surgery

• certain skin cancers, such as basal cell carcinoma, the most common type of skin cancer, as well as squamous cell carcinoma, Bowen disease, and nevoid basal cell carcinoma syndrome (NBCC)

• a type of non-small cell lung cancer that is endobronchial (affecting the lining of the bronchi) and microinvasive (has minimal spread of cancer cells) in patients who can't have other types of treatment, such as surgery or radiation therapy. PDT can be used to shrink tumors that are blocking the airway. This allows patients to breathe easier.

• some tumors of the vagina, vulva, and cervix that can be reached by the activating light

Aminolevulinic acid (ALA or Levulan^®)

Aminolevulinic acid is a drug that is put directly on the skin. It is used to treat actinic keratosis (AK), a skin condition that can become cancer, and mycosis fungoides, a skin lymphoma. It is approved for use only on the face or scalp. A special blue light, rather than laser light, is used to activate this drug.

Methyl ester of ALA (Metvixia^® Cream)

Methyl ester of ALA is one of several other forms of ALA that have been developed. A disadvantage of ALA is that it does not get into the cancer cells very easily. Newer ester forms, such as this one, do. It was approved by the FDA in July 2004 for treatment of non-hyperkeratotic actinic keratoses of the face and scalp. It is activated with a red light.

Verteporfin (Visudyne^®)

Verteporfin has been developed and used to treat age-related macular degeneration, a progressive eye problem that leads to blindness. While it is a PDT, it is not used in cancer treatment and is not discussed in detail here.

Researchers continue to look for new photodynamic therapy drugs and many are being studied in clinical trials. Photodynamic therapy is now being tested for use against several other types of cancer, too. See section "The future of photodynamic therapy."

Revised: 04/23/08