Keloids are unique to humans; hypertrophic scars are similar to keloids and may transform into keloids over time. The standard treatments for these scars are limited by inconsistent efficacy and long treatment/follow-up times. A new treatment that is effective for all abnormal scars is photodynamic therapy (PDT).

A new study published in Scars, Burns & Healing assessed the current evidence regarding the safety and efficacy of PDT for keloids and hypertrophic scars.

Here, a systematic review was conducted including 538 articles from PubMed, Medline and Web of Science, from the year 1900 onwards. Articles were included if they reported using topical PDT to treat keloids or hypertrophic scars; if patient(s) had one or more keloids and/or hypertrophic scars; and when the effect of PDT on these abnormal scars was described.

The results showed encouraging clinical results of PDT on keloids and hypertrophic scars. The findings were summarized as follows – PDT appears to play a promising role in keloid and hypertrophic scar therapy. PDT is a relatively superficial treatment due to its penetration limits of both, the pro-drug and red light. This may be inadequate for keloids, many of which are at least 3 mm deep. Yet, evidence suggests efficacy of PDT treatment in lesions of depths greater than 3 mm, especially, when combined with carbon laser therapy. Additionally, the efficacy of PDT on more superficial layers of abnormal scars indicate that multiple PDT treatments could eventually resolve even thick lesions. Furthermore, the shallow penetration of PDT hints towards its usefulness as an adjunct treatment of the wound area after keloid resection, as well as an aid to prevent postoperative keloid recurrence.

It was stated that further improvements in pro-drugs and light-delivery methods may be needed to assure deep treatment and a more rapid response to PDT. Randomized clinical trials should also be conducted to establish standard guidelines for optimal photosensitizer concentration, incubation period and light source parameters.

Source: Scars, Burns & Healing. 2020 Jun 30;6. doi: 10.1177/2059513120932059.