Photodynamic therapy (PDT) is a non-surgical, light-based treatment designed to target precancerous cells and certain superficial skin cancers. It is often considered by patients looking for a targeted option with minimal downtime that supports favourable cosmetic outcomes.
Dr. Ben Wiese is a family physician (CCFP) with a focused practice in skin cancer. At our private Kelowna clinic, PDT is commonly utilized for conditions such as actinic keratosis and specific types of non-melanoma skin cancer.
In this post, we’ll explore how PDT works, what it is used for, and what to expect before and after your treatment.
What is Photodynamic Therapy?
Photodynamic therapy combines a specific light source and a photosensitizing topical medication to treat targeted abnormal or precancerous cells. The process generally involves three steps:
Step 1: Applying the Photosensitizer
A topical cream is applied directly to the designated treatment area.
Step 2: The Incubation Period
The medication is left on the skin for a set period, typically 1 to 3 hours depending on the product, allowing it to be absorbed by the targeted cells.
Step 3: Light Activation
The area is exposed to a specific wavelength of light. This activates the medication, causing a localized reaction intended to eliminate the targeted abnormal cells.
This targeted process helps limit the impact on surrounding healthy tissue, promoting healing and minimizing long-term scarring compared to more invasive surgical options.
How PDT Works in the Skin
Once absorbed, the topical medication makes the abnormal cells sensitive to specific wavelengths of light. When the light source is applied, it triggers a reaction that generates a targeted form of oxygen, which works to destroy the unwanted cells.
Because the medication is absorbed more readily by abnormal cells than by healthy ones, the treatment is highly focused. This allows for repeated treatments on the same area if clinically indicated, while supporting positive cosmetic outcomes.
To help explain how photodynamic therapy works, here’s Dr. Ben:
Conditions Treated With Photodynamic Therapy
PDT is primarily used for specific skin conditions resulting from chronic sun exposure. It offers a minimally invasive method to address abnormal cells while conserving the surrounding tissue. It is most frequently considered for:
Actinic Keratosis
These precancerous lesions develop from long-term sun exposure and typically present as rough, dry, or scaly spots. PDT is a well-established option for managing multiple lesions across an entire area (field treatment) at once.
This video provides an educational overview of what pre-cancers are and the treatment options available, including PDT and Efudex:
Basal Cell Carcinoma (Superficial Type)
PDT may be an option for certain early or superficial basal cell carcinomas. It serves as a non-surgical alternative that reduces the likelihood of significant scarring, which is often a key consideration for visible areas like the face.
Squamous Cell Carcinoma in Situ (Bowen’s Disease)
This early form of skin cancer is confined to the outermost layer of the skin. PDT can be used to treat these abnormal cells without requiring surgical incisions or sutures.
General Skin Health Observations
While primarily performed for medical indications, a secondary benefit often observed after field treatment for sun damage is an improvement in the overall texture and clarity of the treated skin once healing is complete.
Microneedling Assisted Photodynamic Therapy (mPDT)
For some patients, a specialized approach called Microneedling Assisted Photodynamic Therapy may be considered as an option to address sun-damaged skin and specific precancerous cells (actinic keratosis).
How Microneedling Assisted PDT Works
This method incorporates microneedling prior to the application of the photosensitizing medication (Levulan, or aminolevulinic acid). A nurse melanographer performs a superficial microneedling procedure, using needles set to a very shallow depth (typically 0.20 millimeters). This process creates temporary, superficial channels in the upper epidermis.
The purpose of these channels is to assist the topical medication in reaching the targeted sun-damaged cells more effectively. Once absorbed, the medication converts into a light-sensitive compound, which is subsequently activated by a specific red light source.
The activation phase utilizes a POLY red light device for up to 10 minutes. To help manage the mild to moderate discomfort that can occur during this step, a Zimmer cooling device is used to deliver cold air to the treated area. Both the patient and the nurse wear specialized protective goggles throughout the light exposure.
Clinical Considerations
The primary clinical rationale for incorporating microneedling into the PDT process is to facilitate medication absorption. While individual results vary and outcomes cannot be guaranteed, some clinical studies have observed that this assisted method may contribute to an improved clearance rate of targeted precancerous cells in certain patients when compared to topical application alone. It is important to note that this procedure is not suitable for everyone, and a thorough assessment is required to determine if it aligns with a patient’s specific clinical needs.
The Microneedling PDT Procedure
If Microneedling Assisted PDT is determined to be an appropriate part of your care plan, the general steps include:
- Preparation: Patients are required to arrive with skin completely free of makeup, priming agents, or sunscreen. Clinical photographs will be taken by the nurse for your medical record.
- Cleansing and Numbing: The skin is cleansed, and a topical anesthetic is applied to help manage discomfort prior to microneedling.
- Microneedling: The nurse creates superficial channels in the treatment area at a depth of 0.20 mm.
- Medication Application: The anesthetic is removed, and the Levulan medication is applied. Patients typically experience mild to moderate stinging for approximately one minute during application.
- Incubation: A waiting period of 60 to 120 minutes is required for the medication to absorb. Patients may leave the clinic during this time but must strictly avoid all direct sunlight.
- Light Activation: The area is exposed to the POLY red light while cold air is applied for comfort.
- Post-Treatment: The medication is washed off. Strict post-care sun protection and follow-up instructions will be provided, and adherence is critical for proper healing and safety.
To view an educational overview of the Microneedling Assisted PDT process, you may watch the video below:
Preparing for Your Appointment
A little planning can help your treatment day go smoothly. You may be advised to:
- Avoid heavy sun exposure prior to your treatment.
- Bring a wide-brimmed hat or protective clothing for the trip home.
- Plan for some localized redness afterward, similar to a sunburn.
Your care team will go over specific instructions during your initial consultation.
What to Expect Before and After PDT
During Your Appointment
- Your skin will be cleansed and the photosensitizing cream will be applied.
- You’ll wait 1-3 hours while the medication absorbs into the skin.
- The area will then be exposed to the light for about 15 to 30 minutes. You will wear protective goggles for this step.
- Your nurse will also wear protective eyewear and remain with you for the duration of the light treatment.
After the Treatment
It is normal to experience temporary side effects, including:
- Redness and mild swelling (similar to a sunburn)
- Light peeling, flaking, or crusting for a few days
- Gradual healing within 1 to 2 weeks, typically leaving the skin smoother
Patients generally return for a follow-up assessment in about six weeks to evaluate progress, review clinical photos, and discuss if any further care is required.
To see what happens during the light-activation portion of the treatment, watch the video below:
Benefits of Photodynamic Therapy
Patients often consider PDT for several clinical reasons:
- Minimally Invasive: It requires no surgical cutting or stitches.
- Cosmetic Considerations: It is designed to minimize long-term scarring and support favourable cosmetic outcomes.
- Targeted Treatment: It focuses on abnormal cells while minimizing impact on surrounding healthy tissue.
- Repeatable: The procedure can be safely repeated on the same area if clinically necessary.
- Manageable Recovery: Most patients can resume normal daily activities within a few days, following strict post-care sun protection instructions.
Photodynamic Therapy Cost
The cost of photodynamic therapy varies depending on the size of the treatment area and the number of sessions required. We provide a clear cost breakdown during your consultation.
Please note that while the Medical Services Plan (MSP) of BC does not cover the clinical services associated with PDT, some private extended health insurance plans may offer partial or full coverage for the prescription photosensitizing medication used.
Frequently Asked Questions
Is photodynamic therapy painful?
Some patients experience mild to moderate discomfort or a burning sensation during light exposure. This typically resolves shortly after the session. If you are highly sensitive, after-care medication can be discussed.
How long does the appointment take?
Most appointments last a few hours in total, which includes the cream application, the incubation waiting period, and the light administration.
What should I expect after treatment?
Expect a sunburn-like reaction, localized peeling, and gradual healing over 1 to 2 weeks. It is critical to strictly avoid direct sun exposure on the treated area for at least 48 hours post-treatment.
Is PDT safe for all skin types?
PDT is suitable for a wide range of individuals. Your physician will review your skin type and medical history during your consultation to ensure it is the right approach for your individual needs.
How is PDT different from Efudex?
Efudex (fluorouracil) is a topical prescription cream applied at home by the patient over several weeks, often causing prolonged redness and irritation. PDT is performed entirely in-clinic under medical supervision, involves fewer sessions, and typically features a shorter recovery window. Initial upfront costs differ.
Discuss Your Options
Photodynamic therapy is an established, non-surgical option for managing specific precancerous and superficial skin conditions.
At our clinic, Dr. Ben Wiese provides focused skin cancer screening and primary care services. Patients can access full-body skin examinations, mole mapping technology, and targeted treatment options directly, without requiring a third-party referral.
Our focus is on providing timely access, preventative care, and patient-centred support. If you would like to find out if photodynamic therapy is appropriate for your specific condition, please don’t hesitate to reach out.
Book an Assessment or call (236) 420-3277.