Photodynamic Therapy
Presented by:
Amber Burks
Dental Hygiene Student
Danielle Chelette
Dental Hygiene Student
Lamar Institute of Technology
Introduction of Photodynamic Therapy
o Photodynamic therapy, also called PDT
o An anti-cancer therapy
o Locations PDT is most commonly applied to
o Approval by the U.S. Food and Drug Administration
Importance of PDT
o Alternative treatment option
o Our goal/purpose
o Routine cancer screening
o We hope PDT become more commonly accepted in the
clinical practice
o “prolong survival in patients with inoperable cancers
and significantly improve quality of life”
Photodynamic Therapy
o Three components
1. Photosensitizer
2. Light
3. Oxygen
o Taken separately- non-harmful
o Combined- cytotoxic effects
Process of Photodynamic Therapy
o PDT is a 2 step process
o First step/first appointment
o Administration of the photosensitizer
o Photosensitizer- Light absorbing compound that initiates a
photochemical or photophysical reaction
o Dye
o Administered intravenously or topically
o Several photosensitizers available
o Time period needed between 1st and 2nd step
o Reason for time/theories
Process of Photodynamic Therapy (cont.)
o Second step/second appointment
o Light activation
o Lasers
o Fluorescent lights
o Several factors need to be taken into consideration when
deciding which light source to use.
o Size of the lesion
o Cost
o Absorption rate
o Type of cancer
Process of Photodynamic Therapy (cont.)
o Light gives off wavelengths that are absorbed by the
photosensitizer
o 3 light sources with different penetrating abilities
o Blue light- less penetrating
o Red light- deeper penetrating ability
o When the 3 components are combined it creates a nonthermal (cold) reaction
o Destruction of tumors cells
Disadvantages
o Specialized equipment and training
o Only used for localized tumors
o Dye could unevenly disperse
o Pain and swelling in affected areas after treatment
o Side effects ranging from slight-severe
o May experience lingering photosensitizers in the tissue lasting many
days or weeks (discoloration)
Advantages
o Minimally invasive treatment
o Performed in an outpatient clinic
o Can be used before, during, or after chemotherapy and radiation
therapy
o Can be used where radiation is contraindicated
o Small effect on connective tissues resulting in minimal scarring
o Activates immune system and low systemic toxicity
o High patient tolerance rate
o Lower morbidity and deformity than traditional treatments
o Simple, efficient, and economical
Successful Trial
o Foscan
o 128 patients
o Advanced incurable head and neck carcinomas
o 43% out of 128 showed elimination of their tumor
o 35% had half or greater tumor reduction
o The patients with complete tumor elimination had a 1 year followup
o 35% continued to be cancer free
Clinical Uses
o Standard treatment option for:
o
o

Premalignant esophageal cancer
Early - advanced lung cancer
Process
oIntravenous
administration- Porfimer (Photophrine)
oLight source- laser
o2 (30 min.) treatments
o local/general anesthesia
oDestruction of tumor cells
oRe-evaluate after 1 month
KTP Laser (source of light) With Fiber Optic Catheter and
Light Diffuser
PDT at MD Anderson
Future Research
o Future is promising
o Full potential has yet to be shown
o Continuing research
o New photosensitizers
o Improved existing photosensitizers
o Lower photosensitivity
o Longer light wavelength activation