BACKGROUND: The two-step irradiance schedule in photodynamic therapy(PDT) is an emerging treatment method with a remarkable analgesic effect. We evaluated the influencing factors of pain in condyloma acuminata(CA) treatment with a two-step irradiance schedule. METHODS: All patients were randomly divided into a two-step irradiance group and control group. The two-step irradiance group used 40mW/cm2 for the first 8min, followed by 80mW/cm2 for 16min, while the control group used 80mW/cm2 for 20min. The Numerical Rating Scale(NRS) scores and pain influencing factors were recorded accordingly. RESULTS: In the two-step irradiance and control groups, 64 and 63 patients completed the treatment, respectively. The NRS scores of the two-step irradiance group were significantly lower than that of the control group(P<0.001), with a low fluence rate inducing less pain compared to a high fluence rate(P<0.001). Moreover, when the total fluence accumulated to 57.6J/cm2 , the pain experienced by patients reached its peak. The NRS score of the urethral orifice group was the highest, and the male external genitalia group was the lowest. The NRS score was at its lowest in the first session and highest in the second session. There was a linear relationship between pain and wart size. Among these influencing factors, the fluence rate had the greatest impact on pain. CONCLUSION: The two-step irradiance schedule provides better analgesic effects than standard treatment irradiation while showing similar treatment efficacy. Factors that influence pain include high fluence rate, CA at the urethral orifice, second therapy session, wart size and the interval between CO2 laser and ALA-PDT.
Two-step irradiance schedule for condyloma acuminatum and the influencing factors of analgesic effect: A prospective randomized study