Photodynamic Therapy

by Verónica Ruiz

PHOTODYNAMIC THERAPY IN DERMATOLOGY: AN EFFECTIVE TECHNIQUE WITH GOOD COSMETIC RESULTS

What is phtodynamic therapy?

Photodynamic therapy (PhT) is a noninvasive treatment modality used primarily for the selective elimination of certain types of surfaces of skin cancer.

Its effectiveness is supported by many scientific studies and offers very good cosmetic results, causing minimal damage to the surrounding skin, since it only targets cancer cells (or neoplastic).

It is based on the photooxidation of various tissues induced by a photosensitizing substance which will be selectively absorbed by certain tumor cells or tissues, so that when subsequently illuminated with a light of adequate length and in sufficient doses, these cells will be destroyed.

The cream photosensitizer used mostly in Europe is 5-methyl – aminolevulinate (Metvix® / Ameluz ®).

“PhTrepresents an excellent selective, noninvasive alternative to the treatment of certain types of superficial skin cancer”

Which patients are candidates for PhT?

The use of TFD in dermatology has been increasing in recent years due to numerous studies confirming its effectiveness, safety, comfort and excellent cosmetic results.

Current indications that have not been approved but with good therapeutic results:

  •    Actinic Keratosis
  •     Lip Sun Damage (or actinic queilitis)
  •     Surface basal cell carcinoma
  •    Surface squamous carcinoma or Bowen disease

 

Other indications that have not been approved but with good therapeutic results:

  •   Skin Leishmaniosis
  •  Acne: This therapy works by selectively destroying the sebaceous unit responsible for the genesis and maintenance of acne.
  • Facial rejuvenation: The light used is used to correct blemishes, remove fine wrinkles and tone the skin.  It increases local blood circulation, stimulates collagen production, accelerates healing and stimulates lymphatic activity.
  • Zoon Balanitis
  • Onychomycosis
  • Skin Lymphoma: Several studies demonstrate the complete/partial resolution of fungoid mycosis injuries in initial stages (I-II).
  • Accelerates wound healing: This type of light significantly stimulates the formation of fibroblasts that are the cells responsible for healing.

 

What does the term Cancer field refer to?

It is the skin area that presents significant sun damage (or actinic) accumulated for years and on which we can have clinically objective injuries such as precancerous injuries (actinic keratosis) or skin cancer already established, but in which there are also other non-visual subclinical injuries that could degenerate in the short-medium term, so that PhT would be an adequate therapeutic and preventive modality in this area.

“The application of regular TFD cycles represents a good treatment option for the cancer field and there are even studies that highlight a preventive role of therapy”.

 

What is the procedure?
  1. Scraping the injury by removing the scabs (in the case in which injuries treated are Actinic Keratosis). Occasionally the patient is instructed to apply exfoliating or keratolytic creams (eg: salicylic vaseline) for a few days or weeks prior to the procedure to eliminate scabs and facilitate the penetration of the photosensitizing cream.
  2. Application of the photosensibilizing cream (in occlusion of Metvix® and non-occlusive for Ameluz® in the injury for 2h-2h 30´.
  3. After this time, the area is cleaned with serum and the area is exposed to a red light (630 nm) during 8-9 minutes.
  4. A minimum of 2 sessions with an Interval between them of 2-3 weeks is usual required to achieve the desired effectiveness.

It is not essential that the patient is accompanied on the day performing the technique, unless they are dependent patients.

 

What are the complications of the treatment?
  •  Burning sensation or pain during the exposure to light.

    It is the most common side effect. These discomforts usually begin a few minutes after the application of the light and usually disappear shortly after its completion.  It must be said that its appearance depends on the area in question: the scalp, nose or atrial wards that are areas where patients refer more pain, but there is no doubt that there is great individual variability. Treatment: Methods to relieve this pain include applying fans and cold water during lighting, regular lighting interruption, administering any oral pain and applying local anesthesia prior to lighting; EMLA application is contraindicated because it could interfere with photosensitizer (Metvix®).

  •  Redness (or erythema) and local swelling: they are also common and last between 24-48 hours after treatment.  The appearance of blisters, intense necrosis or ulceration are exceptional. Treatment: Hydration or application of a low potency topical corticosteroid.
  •  La local skin photosensitivity also exists, only in the area of application of the cream and lasts for 24-48 hours, so it is recommended that patients have the affected area covered with a dressing during that times.
  •  Skin hypo-hyperpigmentation in the medium-long term.

 

REFERENCES

  • Marilyn T Wan Jennifer Y Lin. Current evidence and applications of photodynamic therapy in dermatology. Clinical, Cosmetic and Investigational Dermatology 2014:7 145–163.
  • Yolanda Gilaberte, Carlos Serra-Guillén, María Elena de las Heras, Ricardo Ruiz-Rodríguez, Manuel Fernández-Lorente, Cristiane Benvenuto-Andrade et al. Photodynamic therapy in dermatology. Actas Dermosifiliogr 2006 Mar;97(2):83-102.
  • Morton C, Szeimies RM, Sidoroff A, Wennberg AM, Basset-Seguin N, Calzavara-Pinton P et al. European Dermatology Forum Guidelines on topical photodynamic therapy. Eur J Dermatol Jul-Aug 2015;25(4):296-311.