Photodynamic therapy of the experimental tumors of different morphological types with liposomal boronated chlorin е6

The article summarizes the results of studies of the effectiveness of photodynamic therapy using a new domestic photosensitizer liposomal borated chlorin e6 (LBC) after its parenteral administration (intraperitoneal and intravenous). Antitumor efficacy was evaluated in rats with M-1 sarcoma and PC-1 alveolar liver cancer and mice with B16 melanoma and Ehrlich’s carcinoma, which were transplanted subcutaneously into the thigh area of the animals. The aim of the study was to determine the optimal regimes of photodynamic therapy that would allow achieving the maximum antitumor effect up to 21 days after the photodynamic therapy. The therapy was carried out under the control of the accumulation of the photosensitizer in the tumor and surrounding tissues of the thigh by selecting the doses of the drug and the parameters of laser radiation (energy density and power density). The effectiveness of therapy was assessed by the inhibition of tumor growth, by the percentage of animals with complete tumor regression, by the absolute growth rate in animals with continued tumor growth compared to controls. The results of our studies have shown that the domestic photosensitizer liposomal borated chlorin e6 has high antitumor activity in vivo. In an experimental study of the photosensitizer under certain PDT modes, the maximum antitumor effect (complete tumor regression in 100% of animals) was obtained up to 21 days after PDT in all tumor models used.

Transpupillary laser thermotherapy of retinoblastoma

Introduction. Despite the fact that transpupillary thermotherapy (TTT) is one of the main local methods of small retinoblastoma (RB) destruction, only a few studies have been published on the use of this method, and they are devoted only to certain aspects of the application of TTT.Purpose of the study – to evaluate the effectiveness of TTT in the treatment of children with RB.Material and methods. In the period from 2011 to 2020, 177 children (224 eyes, 1156 tumors) with RB were treated by TTT. Of these, 99 (56 %) patients were boys, 78 (44 %) – girls. The mean age at the time of treatment was 16.8 months (from 0 to 86 months). Bilateral RB was observed in 128 (72.3 %) patients, monolateral – in 49 (27.7 %). In 51 (28.8 %) cases, TTT was performed on an only eye. TTT was performed on eyes that had RB of groups A (n = 43; 19 %), B (n = 81; 36 %), C (n = 31; 14 %), D (n = 63; 28 %), E (n = 6; 3 %). In total, 1156 tumors were treated by TTT. 488 (42 %) tumors were localized post-equatorially (of which 27 were located juxtapapillary, 23 – in the macular zone, 22 – paramacular). 668 (58 %) foci had pre-equatorial localization (on the middle and far periphery of the fundus). The number of foci in one eye varied from 1 to 48 (mean – 5). The mean tumor thickness was 1.1 mm (from 0.2 to 4.5), the mean base diameter was 2.2 mm (from 0.3 to 13.4). TTT was performed using a diode laser with the following parameters: wavelength – 810 nm, spot diameter – 1200 microns, power from 200 to 800 mW (mean – 350 mW), exposure-from 3 to 15 s in the application mode, and continuous in the scanning mode.Results. Complete tumor regression after TTT was achieved in 92 % of cases (1064 tumors). Incomplete regression of the tumor with stabilization was achieved in 0.7 % (8 tumors). The average number of TTT sessions to achieve full regression was 1.7 (from 1 to 10). Complete tumor regression after 1 TTT session was achieved in 54 % of cases (622 tumors), after 2 sessions – in 11 % (132 tumors), after 3 sessions – in 7 % (85 tumors), after 4 or more sessions– in 19 % (225 tumors). In 7 % of cases (82 tumors), due to the progression of the tumor, other treatment methods (brachytherapy, cryotherapy, stereotactic radiosurgery) were applied. 209 (93 %) eyes were preserved. 15 (7 %) eyes were enucleated due to continued tumor growth, total retinal detachment, vitreous hemorrhage, or subatrophy of the eyeball. The mean follow-up after TTT was 35.5 months (from 3 to 112 months).Conclusion. TTT is a highly effective method of RB treatment and can be used for destruction of small primary foci of both post-equatorial and pre-equatorial localization, residual tumors after inefficiency of other local methods. TTT is also effective in the treatment of large cavitary tumors located in functionally significant areas of the retina.

Adolescent Plaque Brachytherapy for Large Choroidal Metastasis from Lung Carcinoid Tumor

The purpose of this publication is to report a child with choroidal metastasis from a primary lung carcinoid tumor treated with 125-iodine plaque brachytherapy while achieving complete tumor regression. A 15-year-old girl with a history of stage IV lung carcinoid tumor developed painless progressive visual loss in her right eye. Ophthalmological exam documented a unilateral solitary large choroidal mass with complete exudative retinal detachment. Planned palliative treatment with plaque brachytherapy was performed utilizing a total dose of 45 Gy to the tumor apex. No tumor regression was noted after 6 months of follow-up. Ten months after primary therapy, re-treatment with a total dose of 90 Gy to the tumor apex was performed due to tumor progression. Complete regression was achieved after secondary treatment without evidence of recurrence after 18 months of follow-up. In conclusion, high-dose plaque brachytherapy may induce complete tumor regression in select adolescent patients with choroidal metastasis from lung carcinoid tumor.

The effect of transcriptional activity of genes regulating DNA repair and apoptosis on the effectiveness of radiation therapy in rectal cancer patients.

e13531 Background: Preoperative radiation therapy (RT) followed by surgery is the main effective treatment for colorectal cancer. However, some patients do not respond to preoperative RT due to the radioresistance of tumor cells, depending on their molecular characteristics, in particular on the expression of a certain group of genes. The aim of this work was to study the effect of expression of BRCA2, H2AX, RBBP8, CASP9 and BCL2 genes on the effectiveness of preoperative RT for rectal tumors. Methods: In the study, paired biopsy preparations (obtained by VCS before irradiation) of normal and tumor tissues of the rectum (adenocarcinoma G1-2) in 30 patients were used. RT was carried out on a Novalis TX linear accelerator (Varian, USA) (SFD = 2.4 Gy to TFD = 54 Gy). RNA isolation was performed by Chomczynski&Sacchi method. Reverta-L kits were used to synthesize cDNA libraries. Using the RT-qPCR method, the relative expression of 5 genes was determined: BRCA2, H2AX, CASP9, RBBP8 and BCL2 (reference GAPDH, ACTB and B2M). Statistical analysis was performed using the Shapiro–Wilk and Mann–Whitney criteria. Results: 2 clusters of patients were identified that differed in the expression of the BRCA2, H2AX, CASP9, RBBP8 and BCL2 genes. In cluster 1, 81% of patients had increased expression of the CASP9 gene and 100% decreased expression of the BRCA2, H2AX, RBBP8, and BCL2 genes. In cluster 2, the expression of the CASP9 gene was reduced in 100% of patients and the expression of the BRCA2, H2AX, RBBP8 and BCL2 genes was increased in 93%. A subsequent analysis of the results of RT showed that 16 patients had complete tumor regression after RT, while expression of the H2AX and RBBP8 genes was reduced by a factor of 2 (p < 0.05), and the expression of the CASP9 gene was increased by a factor of 4 (p < 0.005) relative to normal tissues. 8 patients showed slight tumor regression, and 6 patients had no regression at all, while their expression of the BRCA2, H2AX, RBBP8 and BCL2 genes was statistically significantly (p < 0.005) 2, 4, 6 and 3 times higher, respectively, and that of CASP9 gene was 4 times lower than in patients with complete tumor regression. Conclusions: The study found that the expression of BRCA2, H2AX, CASP9, RBBP8 and BCL2 genes affects the effectiveness of RT, enhancing it in patients with increased expression of CASP9 and reduced expression of H2AX and RBBP8, and vice versa, the effectiveness of therapy decreases with increased expression of H2AX, RBBP8, BRCA2 and BCL2.