(A730) Photodynamic therapy for treatment and prevention of recurrent respiratory papillomas: A systematic review and meta-analysis

Introduction: Respiratory papillomas (RP) generally appear in the larynx and can occur as a single or recurring event in those affected. The current mainstay treatment allow for rapid procedures and eliminate the risk of thermal injuries to local tissues, but fibrosis and granuloma formation remain a concern. Treatment with photodynamic therapy (PDT) has also been explored because of its potential to treat RP through a minimally invasive procedure with greater sensitivity against tumors and the possibility of preventing repeated debridement, necessitating a review of current literature and further studies to be conducted on its effectiveness.

Methods: We conducted a systematic review and meta-analyses of studies characterizing the efficacy of PDT for the treatment of recurrent respiratory papillomas, employing PRISMA 2020 guidelines. A comprehensive search of five databases (PubMed, Cochrane Library, Scopus, Embase, Web of Science), yielded a total of 288 articles. Following removal of duplicates, 132 articles remained, and 7 articles met the criteria for full-text analysis. We conducted a single-proportions meta-analysis under the random-effects model using mean modified Kashima indices to assess the effectiveness of photodynamic therapy at reducing the growth rate of respiratory papillomas. Another single-proportions meta-analysis was conducted under the random-effects model using tumor recurrence rates to assess the effectiveness of PDT at preventing recurrence.

Results: The effect size for tumor growth rate in the PDT group was -0.73 which was statistically significant (P=0.03). The effect size for the control group was -0.13 and was not statistically significant (P=0.37). The overall effect size showed a 0.57 reduction in tumor growth rate that was statistically significant (P=0.03). Three studies were utilized for the analysis of disease recurrence; recurrence rate following PDT was determined to be 79% (CI [65%, 93%], P=0.54).

Conclusions: There was determined to be a statistically significant reduction in the growth rate of RP following treatment with PDT and a limited effect of PDT on tumor recurrence.