Vijay R. Patil, M.D., performs photodynamic therapy on a patient at the Thompson Cancer Survival Center. Assisting is Alice Gallegos, research assistant, and Masoud Panjehpour, Ph.D. Sherry Johnson, R.N. is in the background.

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The treatment is called Photodynamic Therapy, or PDT, a new class of treatment that takes advantage of a laser sensitive drug which selectively accumulates in the cancerous tissue.

When the photosensitizer drug, known as Photofrin, is injected into the vein it circulates throughout the body. In about two days, the drug clears out of the normal tissue but remains in the tumor for a longer time. Laser light is then delivered to the area where the cancer is located, activating the drug and rendering it highly toxic to the cancerous tissue.

Since the drug accumulates in the tumor, cancer tissue is destroyed with minimal damage to the surrounding normal tissue. The treatment is delivered using a specially designed fiber optic that transmits laser light through the biopsy channel of an ordinary bronchoscope.

"PDT has an advantage over conventional radiation treatment because it can be used to treat the same area several times if necessary by administration of drug and laser light," said Masoud Panjehpour, Ph.D. Photodynamic therapy has limited side effects and is an outpatient treatment. Following the PDT treatment, destroyed cancer tissue is removed during a follow-up bronchoscopy procedure.

"PDT can be delivered to patients who have been unsuccessful with other therapies such as radiation, chemotherapy, or surgery," said Vijay R. Patil, M.D., a thoracic surgeon working with PDT. "It provides an alternative treatment for relieving symptoms of obstructive cancer within the bronchial tree; however, we should be able to reach the cancer with a bronchoscope before PDT can be used for such patients," said Dr. Patil. "This is necessary since the laser light is delivered through the biopsy channel of the bronchoscope."

A side effect of the drug is skin sensitivity to sunlight. "Patients need to stay away from direct sunlight for four to six weeks," said Dr. Panjehpour. "Exposure to sunlight and bright artificial lights may cause a severe sunburn."

An estimated 172,000 patients are diagnosed with lung cancer each year. Approximately 20,000 to 25,000 patients may be candidates for palliative treatment using photodynamic therapy for relief of symptoms caused by obstruction of airways in late stage non-small cell lung cancer.

The Thompson Center has been involved in the development of photodynamic therapy for a variety of other malignancies such as esophageal cancer, recurrent cutaneous breast cancer, Kaposi's sarcoma, skin cancer, and oral cavity cancers. Photodynamic therapy was developed at the cancer center as an alternative to esophagectomy, the removal of all or part of the esophagus. The mortality rate from an esophagectomy alone is 5 to 10 percent.

For more information on photodynamic therapy (PDT), please call the Thompson Cancer Survival Center's Laser Center at (865) 541-1433.

Vijay R. Patil, M.D., performs photodynamic therapy on a patient at the Thompson Cancer Survival Center. Assisting is Alice Gallegos, research assistant, and Sherry Johnson, R.N. Masoud Panjehpour, Ph.D., is in the background.