Isolated Transpupillary Photodynamic Therapy in Local Treatment of Choroidal Melanoma

Objective : To evaluate the long-term results of local application of transpupillary photodynamic therapy (PDT) with chlorine photosensitizer in isolated organ-preserving treatment of uveal melanoma (UM) and to determine predictors of its effectiveness. Patients and methods . Retrospective analysis of transpupillary PDT efficacy in 38 patients (38 eyes) diagnosed with choroidal melanoma (CM) treated between 2016 and 2024. The median follow-up time was 24 months. The mean age was 62.77 ± 10.89 years. Distribution according to TNM: I (n = 12), IIA (n = 20), IIB (n = 6). According to ultrasound Doppler, the initial tumor thickness before treatment ranged from 1 mm to 5.2 mm, with a median value of 2.95 (2.2; 4.0). Distribution by degree of vascularization: avascular СM (n = 4), hypovascular CM (n = 12), hypervascular CM (n = 22); by degree of pigmentation: weak (n = 22), moderate (n = 11), severe (n = 5). In a multivariate statistical analysis of predictors of transpupillary PDT efficacy, the following features were taken into account: tumor thickness, the degree of pigmentation, and the degree of UM vascularization. Results . Complete regression was achieved in 32 of 38 patients (84 %). After treatment, the tumor thickness ranged from 0 to 4 mm, the median value was 0.5 (0.3; 1.0). Mean best corrected visual acuity before treatment was 0.70 ± 0.34 and 0/38 ± 0.37 after treatment. Multivariate analysis of predictors of treatment efficacy reveal that the most significant criterion was the degree of CM vascularization (AUC = 0.906 (0.802; 1.000), p = 0.002). Complete regression was achieved in 100 % of cases with hypervascular UM, 75 % with hypovascular, and 25% with avascular (p = 0.001). Complete regression was significantly more often observed in small CM (AUC = 0.922 (0.795; 1.000), p = 0.001). The optimal threshold values of the CM thickness for transpupillary PDT in an isolated treatment were obtained: 3.9–4.5 mm. It has been proved that the degree of CM pigmentation is a significant predictor of the absence of complete regression (AUC = 0.805 (0.595; 1.000), p = 0.019), so in the weakly pigmented variant, the formation of an atrophic scar was determined in 21 of 22 patients (95.5 %), in the moderate variant — in 9 of 11 cases (81.8 %), in the case of severe pigmentation in 2 of 5 (40 %) patients (p = 0.012). Conclusions . Transpupillary PDT efficacy in the isolated treatment of small and medium CM is determined by the possibility of achieving complete regression in 2/3 of patients. The identified predictors should be taken into account when conducting this type of treatment.