What is photodynamic
therapy(PDT)?
Photodynamic therapy is a kind of ternary treatment for
cancer involving three key components:A photosensitising
drug, light, and tissue oxygen. It is also being
investigated for treatment of psoriasis and acne, and is an
approved treatment for wet macular degeneration.
In photodynamic therapy, first a photosensitising drug is
administered to the patient.Approximately 24 to 72 later,
the cancerous tissue to be treated is exposed to laser
light which targets cancerous cells. The laser light
activates the photosensitising drug destroying the
cancerous cells without damaging the surrounding normal
tissue.In addition
to directly killing cancer cells, PDT appears to shrink or
destroy tumors in two other ways. The photosensitizer can
damage blood vessels in the tumor, thereby preventing the
cancer from receiving necessary nutrients. In addition, PDT
may activate the immune system to attack the tumor cells.
What types of cancer
are currently treated with PDT?
Food and Drug Administration (FDA) has been approved the
photosensitizing agent called porfimer sodium, or Photofrin®,
for use in PDT to treat or relieve the symptoms of
esophageal cancer and non-small cell lung cancer. Porfimer
sodium is approved to relieve symptoms of esophageal cancer
when the cancer obstructs the esophagus or when the cancer
cannot be satisfactorily treated with laser therapy alone.
Porfimer sodium is used to treat non-small cell lung cancer
in patients for whom the usual treatments are not
appropriate, and to relieve symptoms in patients with
non-small cell lung cancer that obstructs the airways. In
2003, the FDA approved porfimer sodium for the treatment of
precancerous lesions in patients with Barrett’s esophagus
(a condition that can lead to esophageal cancer).
Advantages
It is relatively pain free so little sedation is required.
It is much less riskier than conventional laser therapy.
It has minimal side effects.
PDT does not generate any heat so normal tissue is less
prone to injury.
Possible side
effects
swelling and inflammation
around the region where the surgery occurred which can be
slightly uncomfortable. Also, due to the nature of the
sensitivity to light(skin photosensitivity)
Transient depression
