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Treating Skin Cancers with Mohs Micrographic Surgery and Photodynamic Therapy

Knott Street Dermatology’s specialists are experts in treating skin cancers using various procedures. These include Mohs micrographic surgery and photodynamic therapy (PDT).  Mohs micrographic surgery is a specialized and highly effective skin cancer removal technique that has been proven time and time again. PDT is for precancerous lesions known as actinic keratoses as well as certain types of skin cancers and acne.

Mohs Micrographic Surgery in Portland, Oregon

One of the advantages of this procedure is that unlike other skin cancer treatments, tissues are removed in stages and examined under microscope to gauge the clearance of abnormal cells while the patient waits. This makes Mohs micrographic surgery very precise.

– First, a thin layer of cancerous tissue is removed. 

– Then a second thin layer is removed and examined under a microscope to check for cancer cells. 

– More layers are removed one at a time until the tissue examined under a microscope reveals no remaining cancer. 

With this procedure, minimum normal tissue is removed. Additionally, due to the methodical manner in which the tissue is extracted and examined, Mohs surgery is recognized as the skin cancer treatment with the highest reported cure rate. In the case of squamous cell carcinoma (SCC), the second most common form of skin cancer, Mohs surgery is accepted as the single most effective technique for removal.

Knott Street Dermatology is proud to provide this form of skin cancer treatment in Portland, Oregon.  Additional information about Mohs surgery in Portland can be found on the American Society for Mohs Surgery website at 

Photodynamic Therapy (PDT) in Portland, Oregon

This  procedure treats actinic keratoses (precancerous lesions), certain types of skin cancer, and acne. It is a two-stage treatment combining light energy with a drug (photosensitizer) to destroy said cancerous and precancerous cells after light activation. 

With PDT, a chemical reaction destroys only abnormal cells while leaving normal cells intact. The treatment consists of application of a sensitizing agent – either Levulan (aminolevulinic acid 20%) or Metvixia (methyl aminolevulinate 16.8%) – which is left on the skin and allowed to be absorbed by the abnormal tissue for approximately 1 to 2 hours, followed by exposure to intense light for 15 minutes. 

The chemical photosensitizer is activated by specific wavelengths of light energy and is nontoxic until it is activated. When it is triggered, it becomes toxic to the targeted tissue, making them very sensitive to light, which destroys the malignant cells. So it is very precise and controlled, minimizing any effect on the surrounding tissues. 

After a short healing period, new skin cells replace the abnormal cells. Studies show that this light-based therapy promotes the body’s immune response, helping it destroy cancerous and precancerous cells. 

No treatment has a 100% success rate and treated lesions may not resolve or may recur. Another treatment session may be required for maximum results. 

 PDT is contraindicated for patients with:

◆ Photosensitivity (extreme reaction of skin to sunlight)

◆ Porphyria or sensitivity to porphyrins 

◆ Sensitivity to ingredients in Levulan or Metvixia (including peanut or almond oil)

◆ Pregnancy or breastfeeding

Skin Cancer Treatment at Knott Street Dermatology

If you have any questions about skin cancer, diagnostic procedures or skin cancer treatments in Portland, please contact us to schedule a consultation. Knott Street Dermatology in Portland also meets the needs of patients from nearby Lake Oswego, West Linn, Beaverton and Clackamas.

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