Abstract: 【Abstract】 Objective To investigate the effect of narrow-band ultraviolet B （NB-UVB） phototherapy on the incidence of cutaneous carcinoma, herpes zoster and cataracts in patients with psoriasis vulgaris. Methods A telephone follow-up was conducted among patients with psoriasis vulgaris receiving NB-UVB phototherapy at the Department of Dermatology, Peking Union Medical College Hospital from January 1, 2003 to December 31, 2019. The incidence of cutaneous carcinoma, herpes zoster and cataracts was investigated, and their incidence density and 95% confidence intervals （CIs） were calculated. Subgroup analyses were performed according to the cumulative number of NB-UVB radiation（≤ 100 times, 101 - 300 times, > 300 times）, cumulative radiation energy （≤ 100 J/cm2, > 100 - 500 J/cm2, > 500 J/cm2）, and average radiation frequency （≤ 1.5 times/week, > 1.5 times/week）. Univariate Cox′s proportional hazards regression analysis was conducted to analyze differences in the incidence density of cutaneous carcinoma, herpes zoster, and cataracts between the groups, and the results were expressed as hazard ratios （HRs） and their corresponding 95% CIs. Results A total of 160 patients with psoriasis vulgaris completed the follow-up, including 99 males （61.9%） and 61 females （38.1%）. Their ages （median ［Q1, Q3］） were 39（28.3, 54.8）years, the cumulative numbers of NB-UVB radiation were 129.5 （52, 291） times, the cumulative radiation energy was 226.3 （71.1, 688.9） J/cm2, and the average radiation frequencies were 1.57 （1.37, 1.83） times/week. No cutaneous carcinoma occurred during the follow-up of 1 288.87 person-years （7.77 ［5.11, 9.92］ years）; herpes zoster occurred in 4 cases during the follow-up of 1 273.85 person-years （7.68 ［5.11, 9.88］ years）, and the estimated incidence density of herpes zoster was 31.4/10 000 person-years （95% CI: ［11.8 - 83.5］/10 000 person-years）; cataracts occurred in 8 cases during the follow-up of 1 264.67 person-years （7.72 ［4.84, 9.83］ years）, and the estimated incidence density of cataracts was 63.3/10 000 person-years （95% CI: ［31.7 - 126.2］/10 000 person-years）. No significant differences were observed in the incidence density of herpes zoster or cataracts among subgroups with different cumulative numbers of NB-UVB radiation, cumulative radiation energy and average radiation frequencies （all P > 0.05）. Conclusion The incidence of herpes zoster or cataracts may not be affected by the cumulative number of NB-UVB radiation, cumulative radiation energy or average radiation frequency in patients with psoriasis vulgaris.

Key words: Psoriasis, Ultraviolet therapy, Herpes zoster, Cataract, Cohort studies, Cutaneous carcinoma, Narrow-band ultraviolet B, Safety, Incidence density