Photodynamic Therapy

What Is Photodynamic Therapy?

Back to top

Photodynamic therapy (PDT) is a treatment used to target and destroy dangerous and potentially cancerous cells. The therapy combines light and specific drugs to kill the problematic cells underneath the skin. There are many types of conditions that PDT can treat, given its ability to treat specific areas of the body without debilitating the patient. Speak with your physician to see if photodynamic therapy is a good fit for you and your condition.

What Does Photodynamic Therapy Treat?

Back to top

Photodynamic therapy most commonly treats many forms of cancers as well as non-cancerous conditions. There are different photosensitizer drugs to use in the procedure for different conditions, so the treatment has some flexibility in terms of what it can treat. Below is a list of some of the conditions a doctor might treat with PDT. Note that this list is not all inclusive of all possible conditions for which PDT is a treatment option. The goal for each of these conditions is to use PDT to isolate and kill the cancerous cells before they have a chance to spread to other areas of the body.

Cancerous Conditions

  • Actinic Keratosis – Actinic keratosis is a precancerous cluster of skin cells caused by sun damage over time. Not all actinic keratosis patches on the skin will develop into cancer, but there is enough concern to treat the impacted areas. PDT is used with the sun-damaged skin to kill the cells which may eventually turn into cancer.
  • Cutaneous T-Cell Lymphoma
  • Barrett Esophagus
  • Basal Cell Skin Cancer
  • Throat Cancer
  • Squamous Cell Skin Cancer
  • Non-Small Cell Lung Cancer

Non-Cancerous Conditions 

  • UTIs
  • Periodontal Diseases
  • Sinusitis
  • Gastritis
  • Acne

How Does Photodynamic Therapy Work?

Back to top

PDT works in three steps. First, a doctor will administer a photosensitizer drug in the form of a cream that they rub onto the target area or by IV. The photosensitizer needs time to absorb into the damaged cells and clear out of the healthy cells before the remainder of the therapy can happen. The next step is to allow 1 to 3 days between the initial administration and the rest of the steps to let the medicine be distributed properly.

These are the two most common, FDA approved photosensitizer drugs:

  • Porfimer sodium: Used to treat cancers in the throat and lungs and activates with red light.
  • Aminolevulinic acid: Used as a cream on the skin for precancerous skin areas. This photosensitizer activates with a blue light.

The next part of the therapy is to use a special light to activate the photosensitizer drug that is within the bad cells. Without the light activation, the photosensitizers are non-toxic in the body. However, once activated, the drug becomes toxic to the targeted cells. Doctors use light at a specific wavelength to activate the drug. This is typically a laser or LED. When the light reaches the photosensitized cells, the chemical reaction produces a type of oxygen molecule, which kills the cells.

The doctor will administer the light depending on the area of the bad cells. For cells on the skin, the doctor will aim the light directly at the area. For cell clusters that are internal in the throat or lungs, the doctor will use a camera in your throat to guide the fibre-optic cables with the light down your throat to target the correct area.

How to Access Photodynamic Therapy?

Back to top

A cancer specialist or dermatologist will recommend PDT if the patient would benefit from the treatment. No form of PDT is available by prescription or over the counter. Since it is a procedure, a medical professional must administer both the photosensitizer drug and the light. Depending on the condition, a patient might need a series of PDT sessions to destroy all the damaged cells.

Some insurance plans may cover the cost of the treatments, but the cost does vary. PDT can cost anywhere from $100 to $4,000 per treatment, totaling to many thousands of dollars for a more extensive treatment timeline. Generally, PDT is less expensive than chemotherapy for cancer patients. However, each person’s treatment plan and costs will vary.

What Are the Side Effects of Photodynamic Therapy?

Back to top

After a PDT session, you may experience some mild side effects. The main side effect regards how your body will react to light following the presence of photosensitizer drugs in your system. We list some of the main side effects of PDT below.

  • Sensitivity to bright light: The reaction of the photosensitizer drugs following their exposure to light could lead to a temporary light sensitivity after PDT.
  • Skin changes: You may notice the skin turn red and form blisters after PDT. The light therapy can irritate the skin and may make the treated area itchy or have a burning sensation.
  • Swelling and pain: The treated area may begin to swell due to the impact to the tissue beneath the skin. If the pain worsens in the swelled area, you should contact your doctor.
  • Immune system changes: PDT signals an immune response, so your body may experience a changed immune response. You may be more prone to illness following your treatment.


How Do You Recover from Photodynamic Therapy?

Back to top

Because you may experience side effects after PDT, there are important recovery steps to ensure you do not worsen the effects. Some people may not experience any side effects and feel fine the next day, and others may notice side effects right away. PDT is an outpatient treatment, meaning you do not have to stay in a hospital overnight and will be able to leave not long after the treatment.

To account for potential light sensitivity following PDT, you should aim to control your exposure to light. This means staying out of direct sunlight and bright indirect light. When you do go out, make sure to cover your skin and face with a hat, sunglasses, and other clothing layers. Pay close attention to covering the area that was treated, as that may be especially sensitive.

The duration of the symptoms entirely depends on the person and the strength of the procedure. Your doctor will be able to better advise how long to protect your skin from the sun and any other aftercare measures.

What Are the Benefits and Limits of Photodynamic Therapy?

Back to top

A person’s individual circumstances will impact how effective PDT will be in treating the targeted condition. It is important to note that there are benefits and drawbacks to PDT. Your doctor is the best person to go over the risks and rewards of the procedure before deciding to have the treatment.


  1. Limits damage to healthy cells: The ability to aim the light at the bad cells reduces the light’s ability to damage normal cells surrounding the bad area.
  2. No scarring: PDT leaves no scar following the procedure.
  3. No long-term side effects: PDT has short-term side effects, but none of the effects last longer than a few weeks after the treatment.
  4. Less invasive than surgery: PDT does not require anesthesia, and the patient can leave after the procedure. The treatment does not require any incisions or the like.
  5. Short, outpatient procedure: PDT sessions last around an hour and do not disable the patient.
  6. Costs less: Compared to other cancer treatments like chemo, PDT costs much less and is still effective at treating some cancers.


  1. Can still harm healthy cells: Despite the light’s targeting abilities, there is always the chance that some normal cells will be damaged during the treatment.
  2. Short-term side effects: PDT does cause side effects which may impact the person’s immune system and sensitivity to light. These side effects are temporary, but still important to mention.
  3. Limited use: The lights used in PDT can only reach problem areas that are within 1 centimeter below the skin or in the outer linings of organs. This means that PDT is a viable treatment only for problems close to the surface of the skin or areas like the throat or lungs which are more accessible. Additionally, PDT is only effective for cancers that have not spread to other areas of the body.