Radiation Oncology


Photodynamic Therapy (PDT)

Penn was the first health system in the Philadelphia area to begin researching the use of photodynamic therapy (PDT) to treat cancer. Also known as photoradiation therapy, phototherapy, or photochemotherapy, PDT brings together light-sensitive medication with low-level beams of light to destroy cancer cells.

Research has shown that certain chemicals, known as photosensitizing agents, can kill cancer cells when they are exposed to a particular type of light. PDT uses light-sensitive medication, called a photosensitizing agent, together with low-level beams of light to destroy cancer cells. Depending on the part of the body being treated, the medication is injected into the bloodstream or applied to the skin.

When the treated cancer cells are exposed to the laser, the photosensitizing agent absorbs the light and produces an active form of oxygen that destroys the cancer cells. The agent remains in cancer cells for a longer time than it does in normal cells. Doctors at Penn Cancer Services must time the light exposure carefully so that it occurs when most of the photosensitizing agent has left healthy cells but is still present in the cancer cells.

The laser light used in PDT can be directed through a fiber-optic strand placed close to the cancer cells. The fiber-optic strand can be directed through a bronchoscope into the lungs for the treatment of lung cancer or through an endoscope into the esophagus for the treatment of esophageal cancer.

The Advantage to Patients

Research shows the advantages of PDT include:

  • Minimal damage to healthy tissue
  • Less invasive than surgery
  • Precise targeting of cancer cells
  • Ability to repeat treatments to the same site
  • Less scarring

Type of Cancer Treated with PDT

Currently, photodynamic therapy is being by Penn Cancer Services to treat: