Tumor fluorescence and oxygenation monitoring during photodynamic therapy with chlorin e6 photosensitizer.

BACKGROUND: The study is aimed at developing a method for monitoring photodynamic therapy (PDT) of a tumor using chlorin-type photosensitizers (PSs). Lack of monitoring of chlorin e6 (Cе6) photobleaching, hemoglobin oxygenation and blood flow during light exposure can limit the PDT effectiveness. MATERIALS AND METHODS: Phototheranostics includes spectral-fluorescence diagnostics of Ce6 distribution in the NIR range and PDT with simultaneous assessment of hemoglobin oxygenation and tumor blood flow. Fluorescence diagnostics and PDT were performed using the single laser λexc=660 ± 5 nm. RESULTS: Combined spectroscopic PDT monitoring method allowed simultaneous estimation of Ce6 photobleaching, hemoglobin oxygenation and tumor vascular thrombosis during PDT without interrupting the therapeutic light exposure. CONCLUSION: The developed method of tumor phototheranostics using chlorin-type PSs may make it possible to personalize the duration of therapeutic light exposure during PDT.

Near-infrared phototheranostics of tumors with protoporphyrin IX and chlorin e6 photosensitizers.

BACKGROUND: The study aims to develop a method for phototheranostics of tumors in the near-infrared (NIR) range using protoporphyrin IX (PpIX) and chlorin e6 (Ce6) photosensitizers (PSs) MATERIALS AND METHODS: Phototheranostics includes spectral fluorescence diagnostics of PS distribution and photodynamic therapy (PDT) using a single laser in the red spectral range. PpIX and Ce6 fluorescence were registered in the NIR range. PpIX and Ce6 photobleaching was determined during PDT by the change in PS fluorescence. NIR phototheranostics with PpIX and Ce6 were performed on optical phantoms and tumors of patients with oral leukoplakia and basal cell carcinoma. RESULTS: NIR spectral fluorescence diagnostics of optical phantoms with PpIX or Ce6 is possible when fluorescence is excited by 635 or 660 nm lasers. Fluorescence intensity of PpIX and Ce6 was measured in the range of 725-780 nm. The highest values of signal-to-noise in the case of phantoms with PpIX were observed at λexc=635 nm, and for phantoms with Ce6 at λexc=660 nm. NIR phototheranostics provides the detection of tumor tissues with PpIX or Ce6 accumulation. The PSs photobleaching in the tumor during PDT occurs according to a bi-exponential law. CONCLUSION: Phototheranostics of tumors containing PpIX or Ce6 allows fluorescent monitoring of PS distribution in the NIR range and measuring PSs photobleaching during light exposure that provides personalization of the photodynamic exposure duration to deeper tumors. Using a single laser for fluorescence diagnostics and PDT reduces patient treatment time.

Analysis of the Results of Severe Intraepithelial Squamous Cell Lesions and Preinvasive Cervical Cancer Phototheranostics in Women of Reproductive Age.

(1) Purpose: To investigate the efficacy and safety of using PDT in the treatment of severe intraepithelial squamous lesions of the cervix and preinvasive cervical cancer associated with HPV in women of reproductive age. (2) Methods: The examination and treatment of 45 patients aged 22-49 years with morphologically confirmed HPV-associated cervical intraepithelial neoplasia of a severe degree (17 patients) and preinvasive cervical cancer (28 patients) were performed. All patients underwent PDT of the cervix using a chlorin e6 photosensitizer; after which, the affected areas of the cervix were evaluated using video and spectral fluorescence diagnostics. PDT effectiveness was assessed on the basis of colposcopy data, a cytological examination of exo- and endocervix and PAP test scrapings or the liquid cytology method, and polymerase chain reaction for HPV carriage 4 weeks after PDT, as well as on the basis of histological and immunohistochemical studies of biopsy materials 5 weeks after PDT. The expression levels of the Ki-67 and p16 markers in the affected areas of the cervix were also assessed. (3) Results. All patients included in the study tolerated the intravenous administration of the photosensitizer well, with no side effects or allergic reactions observed. In 88.2% of patients with CIN III/HSIL and in 85.7% of women with preinvasive cervical cancer, the effect of the treatment was noted after the first PDT procedure, while complete regression of the dysplasia foci was observed in 15 women (88.2%) with CIN III/HSIL and in 25 patients (89.3%) with preinvasive cervical cancer. Partial regression to the form of LSIL/CIN I was noted in two cases (11.8%) in the CIN III/HSIL group and in three cases (10.7%) in the group of patients with preinvasive cervical cancer. After PDT, a statistically significant decrease in the expression of the Ki-67 and p16 levels relative to the initial values was noted. (4) Conclusions. The results obtained indicate the high efficiency of PDT with intravenous administration of the chlorin photosensitizer for the treatment of intraepithelial lesions of the cervix with a selective effect on pathologically altered tissue. The use of this approach makes it possible to preserve the normal anatomical and functional characteristics of the cervix, which is especially important for maintaining the fertility of patients.

A method for intra-percardial PDT for malignant mesothelioma.

We describe a case of a 35-year-old patient with recurrent non-resectable pleural mesothelioma cT4N0M0 with a confirmed malignant pericardial effusion, threatening for cardiac tamponade. We performed and described our experience of intrapericardial photodynamic therapy which was well tolerated and with a good survival result. After 12 months of follow-up our patient showed no signs of pericardial effusion and in stable condition, keeping high level of quality of life. This clinical case is an example of the excellent palliative effect of photodynamic therapy together with concomitant immunotherapy.

A Pilot Study of Fluorescence-Guided Resection of Pituitary Adenomas with Chlorin e6 Photosensitizer.

Fluorescence diagnostics is one of the promising methods for intraoperative detection of brain tumor boundaries and helps in maximizing the extent of resection. This paper presents the results of a pilot study on the first use of the chlorin e6 photosensitizer and a two-channel video system for fluorescence-guided resection of pituitary adenomas. The study's clinical part involved two patients diagnosed with hormonally inactive pituitary macroadenomas and one patient with a hormonally active one. All neoplasms had different sizes and growth patterns. The data showed accumulation of chlorin e6 in tumor tissues in high concentrations: Patient 1: 2 mg/kg, Patient 2: 5 mg/kg, and Patient 3: 4 mg/kg. For Patient 1, the residual part of the tumor was not resected since it was intimately attached to the anterior genu of the internal carotid artery. For Patients 2 and 3, no regions of increased Ce6 accumulation were detected in the tumor foci after resection. Therefore, the use of the Ce6 and a two-channel video system helped to achieve a high degree of tumor resection in each case.

Phototheranostics of Cervical Neoplasms with Chlorin e6 Photosensitizer.

(1) Purpose: Improving the treatment effectiveness of intraepithelial neoplasia of the cervix associated with human papillomavirus infection, based on the application of the method of photodynamic therapy with simultaneous laser excitation of fluorescence to clarify the boundaries of cervical neoplasms. (2) Methods: Examination and treatment of 52 patients aged 22 to 53 years with morphologically and cytologically confirmed mild to severe intraepithelial cervix neoplasia, preinvasive, micro-invasive, and squamous cell cervix carcinoma. All patients were carriers of human papillomavirus infection. The patients underwent photodynamic therapy with simultaneous laser excitation of fluorescence. The combined use of video and spectral fluorescence diagnostics for cervical neoplasms made it possible to control the photodynamic therapy process at all stages of the procedure. Evaluation of the photodynamic therapy of intraepithelial cervical neoplasms was carried out with colposcopic examination, cytological conclusion, and morphological verification of the biopsy material after the photodynamic therapy course. The success of human papillomavirus therapy was assessed based on the results of the polymerase chain reaction. (3) Results. The possibility of simultaneous spectral fluorescence diagnostics and photodynamic therapy using a laser source with a wavelength of 660 nm has been established, making it possible to assess the fluorescence index in real-time and control the photobleaching of photosensitizers in the irradiated area. The treatment of all 52 patients was successful after the first photodynamic therapy procedure. According to the PCR test of the discharge from the cervical canal, the previously identified HPV types were not observed in 48 patients. Previously identified HPV types were absent after repeated PDT in four patients (CIN III (n = 2), CIS (n = 2)). In 80.8% of patients, regression of the lesion was noted. (4) Conclusions. The high efficiency of photodynamic therapy with intravenous photosensitizer administration of chlorin e6 has been demonstrated both in relation to eradication therapy of human papillomavirus and in relation to the treatment of intraepithelial lesions of the cervix.

Photodiagnosis and photodynamic effects of bacteriochlorin-naphthalimide conjugates on tumor cells and mouse model.

Photo-induced cytotoxicity and antitumor activity of a series of dual function agents for photodynamic therapy (PDT) and fluorescent imaging based on bacteriochlorin photosensitizer conjugated with various naphthalimide fluorophores was studied in vitro using murine tumor cells of S37 sarcoma and in vivo on mice bearing murine S37 sarcoma. Upon irradiation at the absorption maximum of the photosensitizer, the activity of conjugates was as high as in the case of individual bacteriochlorin, while an additional excitation of the naphthalimide fragment led to an increase in the PDT efficacy due to resonance energy transfer from the fluorophore to photosensitizer. The fluorescence contrast and specific cytotoxic activity measurements indicate that the conjugate of bacteriochlorin with 3,4-dimethoxestyrene-substituted naphthalimide is the most promising agent for the application as theranostic in PDT.

Laser-induced fluorescence diagnosis of stomach tumor.

The purpose of this study is to demonstrate the capabilities of laser spectral and video fluorescence diagnosis used for stomach tumors using 5-ALA photosensitizer. The spectroscopic method is presented with an example of a characteristic fluorescence spectrum from stomach with 5-ALA and quantitative statistics. The laser excitation wavelength was 632.8 nm. The analysis of the video system is presented with clinical statistics. The penetration depth of 3-4 mm of the He-Ne laser during the spectroscopic study allowed for scanning the mucous and submucous layers of the stomach and for detecting tumorous growths in these layers. Registration of fluorescence using the spectral system enabled surgeons to conduct express estimation of dubious stomach tissues, to make biopsy from doubtful areas to reveal precancer and early cancer states. The video fluorescence analysis with the application of 5-ALA-induced PPIX may be recommended for the use as an express method of diagnosis including early diagnosis of malignant stomach diseases as well as for intraoperative assessment of tumor extension and detection of canceromatous foci during laparoscopy. The optimal time interval for the diagnosis (regardless of the nature of the study - endoscopic, laparoscopic, or intraoperative) is 2-4 h from the administration of photosensitizer. The optimal dose of the photosensitizer is 20 mg per 1 kg of the body weight.

New approaches to diagnostics and treatment of cholangiocellular cancer based on photonics methods.

Cholangiocellular cancer (CCC) is an oncological disease of the bile ducts characterized by a high mortality rate. To date, the use of standard methods for the diagnosis and treatment of CCC has not been able to reduce mortality from this disease. This work presents the results of fluorescence diagnostics (FD), which consists in using a modified optical fiber and photodynamic therapy (PDT) using a therapeutic laser instead of a low-intensity laser. This technique was tested on 43 patients in a clinical setting. The results obtained indicate a direct correlation between spectroscopic and video FD methods. Furthermore, a direct correlation was found between the photobleaching of a chlorin e6-based photosensitizer, with the commercial names of Photolon Radachlorin and Photoran and stricture regression. Our findings demonstrate the possibility of using a therapeutic laser with a wavelength of 660 nm for both diagnosis and treatment of bile ducts cancer, which results in a significant reduction of the operation time without decreasing its effectiveness.

Trials of a Fluorescent Endoscopic Video System for Diagnosis and Treatment of the Head and Neck Cancer.

This article presents the results of intraoperative fluorescent diagnostics via the endoscopic system for assessing the quality of photodynamic therapy (PDT) of head and neck cancer. The diagnosis and PDT procedures were performed on the five patients with malignant neoplasms of the vocal cords, lateral surface of the tongue, and trachea and cancer of the left parotid salivary gland. Molecular form of chlorin E6 (Ce6) was intravenously administered with a 1.0-1.1 mg/kg concentration for PDT. Fluorescent diagnostics (FD) was conducted before PDT and after PDT procedures. Control of PDT efficiency was carried out by evaluating the photobleaching of the drug (photosensitizer). The method of intraoperative fluorescent imaging allows determining the exact location of the tumor and its boundaries. The assessment of photosensitizer photobleaching in real time regime allows making quick decisions during PDT procedure, which helps improving the quality of patients' treatment. The results showed the convenience of endoscopic fluorescent video system in various nosologies of head and neck cancer. Therefore, this diagnostic approach will improve the effectiveness of cancer treatment.