Photodynamic Therapy
Photodynamic therapy (PDT) uses a light-sensitive medication called a photosensitizer together with a specific wavelength of light. The drug collects in abnormal cells; when light then activates it, a reaction destroys those cells while largely sparing healthy tissue. PDT is used for certain skin cancers, pre-cancerous lesions and some internal tumors.
Medically reviewed by the Florence Healthcare medical team · Last reviewed June 2026
Overview
Photodynamic therapy works in two stages. First, a photosensitizing drug is applied to the skin or given into the bloodstream, where it is absorbed throughout the body but is retained longer in abnormal and cancerous cells. After a set waiting period, the treatment area is exposed to a specific wavelength of light, often from a laser or LED source. The light activates the drug, producing a form of oxygen that destroys the targeted cells. Because the reaction only happens where both the drug and the light are present, healthy surrounding tissue is largely protected, which often gives good cosmetic outcomes.
PDT is used for several pre-cancerous and early cancerous conditions of the skin, and for some tumors of the esophagus and lung reached using an endoscope. For patients travelling from abroad, an oncology coordinator arranges the assessment, the photosensitizer, the light treatment and follow-up, and explains the important light-sensitivity precautions afterwards. Our specialists can review your pathology, imaging and prior reports remotely beforehand to confirm whether PDT is the right approach for your situation.
Who is a candidate?
- People with actinic keratoses or other sun-related pre-cancerous skin lesions
- Patients with certain early, superficial skin cancers such as basal cell carcinoma or Bowen's disease
- Selected patients with early esophageal cancer, Barrett's esophagus with high-grade changes, or certain early lung tumors reachable by endoscope
- People who prefer a tissue-sparing option with good cosmetic results over surgery, where appropriate
- Patients whose tumor is thin and accessible enough for light to reach effectively
- Those whose case has been reviewed by a multidisciplinary oncology team confirming PDT is suitable
What happens
- 1
Assessment and planning
An oncology or dermatology specialist confirms the diagnosis with examination, imaging or biopsy and decides whether PDT is appropriate and how the photosensitizer and light will be delivered.
- 2
Applying the photosensitizer
The light-sensitive drug is applied as a cream to skin lesions, or given into a vein for internal tumors. A waiting period — from hours to a couple of days — allows it to concentrate in the abnormal cells.
- 3
Light treatment
The treatment area is exposed to a precise wavelength of light. For skin this is done with a lamp or laser; for internal tumors a thin fiber is passed through an endoscope to deliver light directly to the site.
- 4
Immediate aftercare
The treated area may be red, swollen or sore, similar to sunburn. You are given clear instructions on dressings, pain relief and, importantly, avoiding bright light and sun while the drug clears from your body.
- 5
Review and repeat sessions
Your team checks how the lesion has responded and arranges any further sessions. Healing and final results are assessed over the following weeks at follow-up.
Benefits
- Targets abnormal cells while largely sparing healthy surrounding tissue
- Often gives excellent cosmetic results, with less scarring than surgery for suitable skin lesions
- Can usually be repeated to the same area if needed, unlike radiotherapy
- Many skin treatments are done as a quick outpatient procedure without general anesthesia
- Offers an organ-sparing option for some early internal tumors
- Can be combined with other treatments as part of a wider cancer plan
Risks & considerations
- Temporary skin sensitivity to light, requiring you to avoid bright light and sun for a period after treatment
- Redness, swelling, burning, stinging or blistering of the treated area as it heals
- Only effective where light can reach, so it is not suitable for thick or deep tumors
- For internal sites, possible swelling, scarring or narrowing of the treated passage
- More than one session may be needed, and not all lesions respond completely
- Risks and precautions vary by photosensitizer and are explained in detail beforehand
Where it is performed
This procedure is delivered by our Comprehensive Oncology Center.
Learn more before you decide
Provider-reviewed guides on the related conditions, symptoms and tests in our Health Library.
Photodynamic Therapy — frequently asked questions
A light-sensitive drug collects in abnormal cells. When a specific wavelength of light is shone on the area, it activates the drug, producing a reactive form of oxygen that destroys those cells. The effect only occurs where both the drug and the light meet, sparing most healthy tissue.
The photosensitizing drug makes your skin and eyes temporarily sensitive to bright light. Depending on the drug used, you may need to stay out of direct sun and strong indoor light for anywhere from a couple of days to several weeks to avoid a sunburn-like reaction.
During light exposure you may feel warmth, tingling, stinging or burning at the treated area, and afterwards it can feel like sunburn. This is usually manageable with cooling and simple pain relief, and your team will advise on comfort measures.
Some lesions clear after a single session, while others — or larger and internal sites — may need two or more treatments. Your specialist estimates the likely number after assessing your lesion and reviews your response between sessions.
Yes. Our oncology team can review your pathology, imaging and reports remotely before you arrive to confirm whether photodynamic therapy is appropriate for your specific lesion, so your visit and treatment plan are clear in advance.
Cost depends on the photosensitizer used, whether the lesion is on the skin or internal, and how many sessions are needed. After reviewing your case we provide a transparent, personalized estimate covering the treatment and follow-up before you commit.
Related treatments
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