Efficacy of Laser and Light Therapy for the Treatment of Non-Atrophic Scars: A Systematic Review and Meta-Analysis

Background: Scarring is the unavoidable consequence of injury to the skin. Treatment of scars remains a challenge despite the various treatment options available. Within the past decade, laser and light therapy (LLT) has become widely used to treat scars. The purpose of this systematic review and meta-analysis is to evaluate the evidence for the treatment of non-atrophic scars (e.g. linear scars, hypertrophic scars, and keloids) with LLT.

Methods: We performed a systematic review searching PubMed, EMBASE and CENTRAL electronic databases. The methodological quality of controlled clinical trials was evaluated, assigned a corresponding level of evidence and assessed for risk of bias. A meta-analysis of the studies that met the eligibility criteria was performed in order to determine the overall response rate of linear scars, hypertrophic scars (HTS), and keloids following treatment with LLT.

Results: Twenty-eight studies met the eligibility criteria. Most were Level II evidence (n=21), five were Level III and two were Level I. The most common scar type was HTS (n=16), followed by linear (n=9), keloids (n=7), and other or non-specified scar types (n=3). Limited evidence was found for striae distensae (n=1). Most evidence was found for treatment with Er:Glass lasers (n=10) and PDL (n=10), followed by CO2 (n=7) and Er:YAG (n=3). Little evidence was found for diode (n=1) and Nd:YAG lasers (n=1). The overall response rate for LLT was 0.63 (95% C.I. 0.51; 0.74) for linear scars and 0.46 (95% C.I. 0.24; 0.70) for hypertrophic scars. Outcome data was inadequate to determine the response rate for keloids. Of the studies assessing each respective scar characteristic, 100% showed improvement in texture, 75% showed improvement in thickness and pliability, and 44% showed improvement in color.

Conclusion: This study is the first meta-analysis to confirm the efficacy of LLT in the treatment of non-atrophic scars. Treatment with LLT is most effective for improving scar texture and least effective for improving scar color. Despite the numerous studies investigating treatment of non-atrophic with LLT that have been published, poor methodology, insufficient reporting, and lack of universal outcome measures makes determining evidence-based guidelines particularly challenging. This highlights the need for high-quality RCTs with Level 1 evidence and follow-up times of at least 6 months to determine the role of LLT in the treatment of non-atrophic scars.