Photodynamic Therapy for Skin Cancer Explained: How Light Treats Abnormal Cells

Photodynamic therapy for skin cancer is a clinically recognised treatment that uses light‑activated medicine to destroy abnormal cells. Photodynamic Therapy (PDT) is a clinically recognised light‑based treatment that uses a special photosensitive medicine and a targeted light source to destroy abnormal or precancerous cells.

According to the NHS, PDT can effectively treat certain skin, eye, and internal conditions, as well as some early‑stage cancers, without the need for invasive surgery.

How Photodynamic Therapy Works

PDT combines two harmless components:

1. A light‑sensitive medicine
2. A specific light source

The combination of medicine and light therapy creates a powerful, targeted reaction. When light activates the medication, it produces a local chemical reaction that destroys abnormal or unhealthy cells while leaving surrounding tissue largely unharmed.

Because of this precision, PDT allows clinicians to treat small patches of abnormal tissue with minimal scarring and faster recovery compared to surgical removal.

Common Uses of Photodynamic Therapy for Skin and Early Cancers

NHS guidance highlights photodynamic therapy for skin cancer and sun‑damaged precancerous lesions as an important non‑surgical treatment option. The NHS lists several conditions where photodynamic therapy is used, including:

• Actinic keratoses: precancerous, sun‑damaged rough skin patches.
• Bowen’s disease: an early form of non‑melanoma skin cancer.
• Basal cell carcinoma: a common, slow‑growing skin cancer.
• Barrett’s oesophagus: abnormal cell changes in the oesophagus lining.
• Certain lung and oesophageal cancers: to remove or shrink localised tumours or reduce symptoms.

Research is also exploring PDT’s potential for warts, acne, and extramammary Paget’s disease, highlighting its expanding use in both dermatology and oncology.

Treatment Process of Photodynamic Therapy

There are two main types of PDT:

1. Conventional PDT – usually involves a two‑step process.

• • A cream, injection, or drinkable solution delivers the photosensitising medicine to affected cells.
  • After several hours or days, the area is exposed to a controlled light source (often an LED or laser) for 10–45 minutes to activate the treatment.
  • For internal conditions (such as in the lungs or oesophagus), doctors use an endoscope with a light tip to reach internal tissues.

2. Daylight PDT – mainly used for mild skin conditions.

• • The photosensitive cream is applied to the skin.
  • The person then spends around 2 hours outdoors in daylight while protected by sunscreen (SPF 50 or higher) to naturally activate the medicine.

Photodynamic Healing and Aftercare

Healing from PDT takes around 2-6 weeks, depending on the area treated. During this time, the skin may feel warm or tender, and a protective dressing is usually applied.

After daylight PDT, the cream is wiped off, and the treated area is covered or shielded from further light exposure for the rest of the day.

If the medicine is taken internally, patients may experience light sensitivity for several weeks, so public health guidance recommends avoiding bright lights and direct sunlight.

Safety and Side Effects of Photodynamic Therapy (PDT)

NHS guidance confirms PDT as a safe and effective treatment when used for approved conditions. Temporary side effects may include:

• A mild burning or stinging during light exposure.
• Redness, swelling, or itching of treated skin.
• Sensitivity to light for up to 6 weeks (when medicine is ingested or injected).

Very occasionally, the skin may lighten or darken, or hair may thin in the treated area, but most reactions subside as healing progresses.

Conclusion of PDT

Photodynamic Therapy represents an advanced medical application of light, combining science and precision to treat abnormal cells painlessly and effectively.

To learn more or read the full NHS explanation, visit the official page:
👉 NHS Photodynamic Therapy Guide