Authors have studied the antitumor efficacy of contact radiation therapy (CRT) in combination with a chlorin-based photosensitizer (PS) in an experiment on laboratory animals with transplanted tumors. The experimental study was performed in 50 white outbred rats weighing 250±50 g. Subcutaneously transplanted Pliss lymphosarcoma (PLS) and alveolar liver cancer RS1 (RS1) were used as tumor models. Chlorinbased PS photolon (RUE «Belmedpreparaty», Republic Belarus) was injected intravenously at a dose of 2.5 mg/kg. The radiation sessions were carried out 2.5–4 hours (depending on the tumor model) after the administration of the PS using the device «microSelectron HDR V3 Digital» («Nucletron», Netherlands) with a 192-Ir radiation source in single focal doses 5 and 10 Gy. All laboratory animals (for PLS and RS1) were subdivided into 5 groups of 5 animals each: intact control, CRT 5 Gy, CRT 10 Gy, PS + CRT 5 Gy, PS + CRT 10 Gy. For the PLS tumor model – on the 14th day from the beginning of the experiment Vav. in groups were 26.31±5.81; 22.45±6.97; 18.99±4.86; 10.75±5.18 and 28.06±2.85 cm3, respectively (p˂0.05). The coefficients of tumor growth inhibition in the experimental groups were 14.67%, 27.82%, 59.14% and 6.65%, respectively. The frequency of complete tumor regressions 60 days after the start of the experiment was 0%, 20%, 20%, 60%, and 20%, respectively. On RS1 tumor model – on the 14th day from the beginning of the experiment Vav. in groups were 4.48±1.03; 0.80±0.21; 0.29±0.09; 0.19±0.07 and 0.32±0.08 cm3, respectively (p=0.009). The coefficients of tumor growth inhibition in the experimental groups were 82.14%, 93.53%, 95.76% and 92.86%, respectively. The frequency of complete tumor regressions 60 days after the start of the experiment was 0%, 0%, 20%, 0%, and 0%, respectively. Systemic administration of chlorin-based PS before the CRT session increases the antitumor efficacy of radiation therapy in animals with transplantable tumors of different histological structure and growth patterns. The data obtained indicate that further studies of the radiosensitizing properties of PS are promising.

Photodynamic therapy is a relevant and promising area for research in the field of clinical neuroonocology. Application of modern developments in the field of laser technologies and new photosensitizers allows us to refer to this field as to high-tech. According to various authors, the inclusion of photodynamic therapy in combined and complex treatments of patients with malignant brain tumors allows achieving overall survival median of patients from 11 to 26 months for primary form of glioblastoma, and from 7.5 to 15 months - for recurrent forms of glioblastoma. Certain results have been achieved in the treatment of patients with metastatic brain lesion. In this publication the authors analyzed and systematized the results of the main clinical studies in the field of fluorescent diagnostics and intraoperative photodynamic therapy of primary, recurrent and metastatic forms of malignant brain tumors.

In the present publication, authors have analyzed the results of using sonodynamic and sono-photodynamic therapy with photosensitizing agents of various classes (hematoporphyrin, 5-aminolevulinic acid, chlorin derivatives, etc.) in experimental oncology. In a number of in vitro and in vivo studies, the high antitumor efficacy of the above treatment methods has been proven. Ultrasonic treatment with a pulse frequency of 1–3 MHz and an intensity of 0.7 to 5 W/cm2 , independently and in combination with photo-irradiation of experimental tumors, can significantly improve the cytotoxic properties of photosensitizers. This became the basisfor testing the methodsin patients with malignant neoplasms of various localizations. Scientists fromSouth-East Asia presented the preliminary results of the use of sonodynamic and sono-photodynamic therapy with photosensitizers in the treatment of malignant pathology of the mammary gland, stomach, esophagus, prostate, lung and brain. Analysis of the obtained data indicates the absence of serious adverse events and an increase in the antitumor efficacy of treatment, which included these treatment methods with chlorin-type photosensitizers.

This review article discusses the key aspects of the use of laser technologies, namely, laser vaporization (LV) and photodynamic therapy (PDT), in the treatment of patients with cervical intraepithelial neoplasia (CIN). The authors analyzed and systematized the foreign experience of these methods of treatment, their indications and contraindications, as well as the advantages over traditional approaches to the treatment of this pathology. The main advantages of the LV are the possibility of complete evaporation of the pathological focus, visual control over the depth of tissue destruction, the absence of prolonged edema and cicatricial deformities, which allows maintaining the integrity of the cervix and its reproductive function. Despite the low trauma and low frequency of adverse reactions, the data on the effectiveness of LV are quite contradictory and, according to various authors, vary from 50% to 98%. To date, there is a significant amount of accumulated experience in the use of PDT with various photosensitizing agents (5-aminolevulinic acid (5-ALA), hematoporphyrin and chlorin and their derivatives) in the treatment of patients with CIN. The main advantages of the PDT are minimal toxicity to the surrounding normal tissues due to the selective accumulation of photosensitizer in pathological tissues, a low risk of severe pain syndrome, the absence of mechanisms of primary and acquired resistance, the possibility of an outpatient treatment session, the possibility of combining with other methods of therapeutic action, the absence of limiting cumulative doses of photosensitizers and light exposure, the possibility of multiple repetitions of the session, good cosmetic results and the possibility of implementing an organ-preserving method of treatment. The obtained results indicate good tolerability of the method (no severe adverse reactions) and a fairly high efficiency of PDT: the frequency of complete regressions varies from 30% to 67% - for application forms of 5-ALA and from 90% to 98.1% - for hematoporifirin and chlorin photosensitizers. Thus, LV and PDT can be considered safe and effective treatment options for patients with CIN.

Objective of the study was to evaluate the tolerability and effectiveness of photodynamic therapy (PDT) in patients with vulvar premalignant diseases.Materials and methods. Study was performed in 10 patients on the basis of the National Cancer Institute of Ukraine (Kyiv). Age of patients ranged from 31 to 67 years old (mean age 53.3 ± 3.6 years old). Diagnosis was made on the basis of medical history, complaints and clinical examination of patients, vulvoscopy and results of morphological examination of pathologically altered vulvar tissues. A drug of the chlorine series “Photolon” (RUE “Belmedpreparaty”, Republic of Belarus) in doses from 1 to 2.5 mg/kg was used as a photosensitizer (FS). Photoirradiation of pathologically altered foci was performed 3–4 hours after the end of the FS infusion using a laser coagulator universal “Lika-surgeon” (“Photonics Plus”, Ukraine, λ = 660 nm) with a radiation power of 0.4 W in exposure doses of 100 up to 150 J/cm2. PDT tolerability was assessed basing on the frequency and severity of adverse reactions (CTCAE, version 3.0). PDT effectiveness was assessed basing on the presence/absence of complaints, data from visual observation of changes in the area of treated lesions and morphological examination data at 3 and 6 months after treatment (WHO criteria).Results. No serious adverse reactions associated with FS infusion and PDT session were observed: no allergic reactions (Quincke’s edema, urticaria, drop in blood pressure, bronchospasm), no symptoms of skin phototoxicity. There was remission of clinical symptoms (itch in the area of vulva) in the treated pathological centers and high frequency of clinical and morphological regressions in the control observation terms of patients.Conclusion. Obtained results indicate the relevance and prospects of further researches in the field of laser technology and PDT as options for organ-preserving treatment of vulvar premalignant diseases