Alexandra ³§Âáö³ó´Ç±ô³¾: Simulated daylight – a new opportunity for pain-free treatment of sun-damaged skin
Alexandra ³§Âáö³ó´Ç±ô³¾ has investigated the effectiveness and patient experiences of two different types of photodynamic therapy (PDT) for superficial basal cell carcinoma and actinic keratoses. The results show that SDL-PDT causes less pain and fewer side effects compared to C-PDT. However, healing outcomes one year after treatment were slightly lower with SDL-PDT than with C-PDT. Despite this, many patients preferred SDL-PDT because it was significantly gentler.
ALEXANDRA SJÖHOLM
Dissertation defense: 5 juni 2025 (click for details)
Doctoral thesis:
Research area: Dermatology and Venereology
Sahlgrenska Academy, The Institute of Clinical 91̽»¨s
Early precancerous skin changes, known as actinic keratoses, as well as superficial basal cell carcinoma, are common among individuals with high sun exposure. There are several effective treatment options, and one of them is conventional photodynamic therapy (C-PDT) using red light. This method involves applying a medication to the affected skin, followed by light exposure to activate the drug. While the treatment generally leaves no scarring, the intense pain experienced during light exposure is a well-known challenge.
"Many attempts have been made to reduce the severe pain associated with C-PDT, but the methods have either proven ineffective or painful themselves," says Alexandra ³§Âáö³ó´Ç±ô³¾, research nurse at the Department of Dermatology and Venereology at Sahlgrenska University Hospital, and a doctoral student at the Institute of Clinical 91̽»¨s.
Using natural daylight outdoors has shown promising results in reducing the pain associated with photodynamic therapy. However, this approach is highly weather-dependent and exposes patients to additional harmful UV radiation.
"To offer patients photodynamic therapy without acute pain regardless of the season, a new lighting system using simulated daylight, known as simulated daylight photodynamic therapy (SDL-PDT), has been developed."
Patients Appreciate the Pain-Free Treatment
The results show that SDL-PDT is significantly less painful than C-PDT, although the medical effectiveness is slightly lower.
"Studies show that patients value the pain-free experience, but continued research is needed to optimize the method and ensure long-term effectiveness. The practical benefit is that healthcare providers now have more information to make informed choices based on both clinical outcomes and patient experience."
In some cases, SDL-PDT may be a very good option—especially for patients who are sensitive to pain, or when daylight-based therapy is needed year-round regardless of weather conditions.
Working at the Intersection of Medicine and Nursing Has Been Rewarding
"The most rewarding part has been working at the intersection between medical research and nursing, where I could highlight both clinical results and patient experiences. It has sometimes required careful planning and organization, but it has also given me a strong connection to real-world practice, making the project especially meaningful. One challenge, however, has been time—at times, I haven’t been able to train as much with my road cycling friends as I would have liked.
Text: Susanne Lj Westergren