Light-Activated Treatment
Photodynamic therapy
Photodynamic therapy (PDT) combines a light-sensitive agent with light of one defined wavelength: the agent collects in the target tissue, the light activates it, and the oxygen radicals that form destroy the cells around it. St. George Hospital uses PDT for tumors on or near the surface of the body that light can reach, alongside standard oncology, and in selected chronic infections as an individual treatment attempt.
What is photodynamic therapy?
Photodynamic therapy destroys tissue with three things that are harmless on their own: a photosensitizing agent, light of one wavelength, and oxygen. St. George Hospital uses it within its integrative oncology work for tumors that light can reach, and in a defined place inside the Lyme program.
The agent is applied to the skin or given by infusion and collects more in fast-dividing or inflamed tissue than in the healthy tissue around it. After a waiting period the physician shines light of the wavelength the agent absorbs onto the area, from a lamp, a laser or a fiber placed next to the tumor. The energized agent passes its energy to oxygen, and the reactive oxygen species that form damage cell membranes and the small vessels that supply the tumor. The treated tissue dies over the following days and a local inflammatory reaction clears it. Tissue that absorbed little agent, or that the light did not reach, is spared.
The depth of the effect is set by the light: red light penetrates a few millimeters of tissue, so PDT treats lesions on the surface or those that a fiber can be brought next to. It cannot reach a deep tumor from outside.
What conditions is it used for?
The physician decides from your findings whether a lesion is accessible to light and which agent and route are appropriate. PDT is used for:
- Precancerous and superficial skin lesions, where PDT is an established, guideline-listed option
- Tumors on the surface of the body or just below it, including skin metastases of breast cancer and chest-wall recurrences
- Tumors that a light fiber can be placed against, for example in hollow organs, in coordination with the treating specialist
- Localized prostate cancer in selected cases, after the physician has reviewed the imaging
- Chronic Lyme disease and persistent infections, as an individual treatment attempt within the program
PDT is not used in porphyria or known allergy to the photosensitizer, in pregnancy, in severe liver impairment when the agent is given intravenously, or for tumors that lie deeper than the light reaches. It does not treat disease that has spread beyond the lit area. Outside the approved skin indications, PDT at the hospital is an individual treatment attempt decided with the patient after medical consultation.
Could this belong in your plan?
Send your imaging, your pathology and photographs of any visible lesion. A physician reads them before the video consultation and tells you whether the lesion is accessible to light and which agent would be used.
How a session runs
- The agent. For skin lesions a cream containing the photosensitizer is applied and covered; it needs about three hours to collect in the lesion. For deeper or larger targets the agent is given by infusion, and the wait before the light is hours or, with some agents, one to three days. During this wait you stay indoors and away from bright light.
- Before the light. The physician marks the field, checks the skin and, for a fiber treatment, places the fiber under imaging guidance. Eye protection is put on.
- During. The lamp, laser or fiber delivers light of the agent's wavelength for 15 to 45 minutes, depending on the size of the field and the dose. You feel warmth. Topical PDT on the skin can sting or burn during the exposure; the nurse cools the area and pauses the light if needed. Intravenous PDT is usually painless during the light itself.
- Afterwards. The treated area turns red and swollen within hours and can be sore for a few days; superficial lesions crust and heal over one to three weeks. After an intravenous agent your skin and eyes stay sensitive to bright light for a period the physician specifies: sunglasses, long sleeves and shade until it has passed. The first assessment of the lesion is scheduled at two to four weeks, when the inflammation has settled.
Larger areas or thicker lesions are treated in two or three light sessions, one to two weeks apart.
Evidence and safety
The evidence depends on the indication and is strong in approved dermatological uses such as actinic keratosis. After an intravenous agent, skin and eyes stay sensitive to light for a time.
Show studies, risks and side effects
The evidence for PDT depends on the indication. In approved dermatological indications it is strong. The 2021 guidelines of the American Academy of Dermatology list PDT among the treatments for actinic keratosis (Eisen et al., J Am Acad Dermatol, 2021), and a meta-analysis of six randomized trials with 369 patients found daylight PDT and conventional red-light PDT with methyl aminolevulinate comparable for clearance of these lesions (Mei et al., Photodiagnosis Photodyn Ther, 2019).
In early-stage tumors the evidence is moderate. The review by Agostinis et al., CA Cancer J Clin, 2011 describes PDT as a clinically approved, minimally invasive procedure with selective activity against malignant cells, useful mainly in early-stage tumors, with low normal-tissue toxicity and the advantage that tumors do not develop resistance to it. In prostate cancer the evidence is emerging: a randomized phase 3 trial of a vascular-targeted photosensitizer against active surveillance in 413 men with low-risk disease found less progression at 24 months and more negative biopsies in the treated group, with urinary retention and prostatitis as the main adverse events (Azzouzi et al., Lancet Oncol, 2017). That trial used one specific agent and protocol; it supports the principle, and the physician will tell you whether a comparable approach applies to your findings.
What the evidence does not show: for PDT with systemic photosensitizers in other solid tumors, and for PDT in Lyme disease and other persistent infections, there are no controlled clinical trials. We found no clinical trial of PDT in Lyme disease in PubMed. These uses rest on laboratory work on antimicrobial photodynamic effects and on clinical experience, and the hospital grades them as limited.
Safety: the risks are local inflammation, pain and, rarely, infection of the treated area, and light sensitivity of the skin and eyes after an intravenous agent, which is managed by the protection rules above. PDT does not affect blood counts or organ function in the way systemic chemotherapy does. The hospital photographs and measures the lesion before treatment and at the follow-up, so that the result is documented for you and your oncologist at home.
How it fits the program
At St. George Hospital, photodynamic therapy is a local measure inside a plan written from your findings by Dr. Martin Rößner, Chief Physician, and the clinical team using protocols developed under Dr. Julian Douwes, and it is used alongside standard oncology, never in place of it. PDT may be considered for selected accessible lesions after medical review. PDT of a tumor region is often combined with local-regional hyperthermia, and the systemic side of the plan can include low-dose chemotherapy with insulin and immune therapy. In the Lyme program, PDT is one optional element next to whole-body hyperthermia and antimicrobial therapy.
How these elements are sequenced over a two to four week stay is described on the page for our integrative oncology program in Germany.
Costs
Treatment at St. George Hospital is self-pay. PDT is billed per session, including the photosensitizer, inside the itemized estimate in EUR that you receive after a physician has read your findings. Costs are a package price plus individual add-ons, and a deposit is paid before admission. The invoice after the stay is itemized in English with diagnoses and procedure descriptions for an out-of-network claim. Details are on costs and insurance.
Questions patients ask about photodynamic therapy
Does photodynamic therapy hurt?
Light exposure is generally painless; you feel warmth from the lamp or the fiber. Topical PDT on the skin can sting or burn during the exposure, which is handled with cooling and pauses. After the session the treated area can be red, swollen and sore for a few days, like a sunburn, before it heals.
Is PDT safe?
The main risk is light sensitivity. After an intravenous photosensitizer your skin and eyes react to bright light for a period that the physician specifies, and you wear sunglasses and long sleeves until it has passed. PDT is not used in porphyria, in allergy to the agent, in pregnancy, or for tumors that lie deeper than light reaches.
Can PDT replace surgery or radiotherapy?
Only where guidelines already name it as an option, for example in some actinic keratoses and superficial basal cell carcinomas. For other tumors the hospital uses PDT alongside or after standard oncology and after consultation with your oncologist. It does not treat disease that has spread beyond the lit area.
Why is PDT used in Lyme disease?
Photosensitizers also damage bacteria when activated by light, which is studied as antimicrobial PDT. We found no clinical trial of PDT in Lyme disease, so this use rests on laboratory work and clinical experience. It is an individual treatment attempt inside a Lyme program, never its core, and the physician explains that before you consent.
How much does PDT cost?
This page lists no prices. PDT is billed per session, including the agent, inside the itemized estimate you receive after a physician has read your findings. The written cost overview shows every item. See costs and insurance.
If you want to know whether a lesion can be treated with light, send your imaging and a photograph of the area. A physician reads them before the video consultation and answers in writing.
References
- Photodynamic therapy of cancer: an update.. CA Cancer J Clin 2011. PMID 21617154
- Guidelines of care for the management of actinic keratosis.. J Am Acad Dermatol 2021. PMID 33820677
- Daylight versus conventional photodynamic therapy for the treatment of actinic keratosis: A meta-analysis of randomized controlled trials.. Photodiagnosis Photodyn Ther 2019. PMID 30412779
- Padeliporfin vascular-targeted photodynamic therapy versus active surveillance in men with low-risk prostate cancer (CLIN1001 PCM301): an open-label, phase 3, randomised controlled trial.. Lancet Oncol 2017. PMID 28007457
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