Wojciech Latos

Comparison of cryotherapy and photodynamic therapy in treatment of oral leukoplakia

Oral leukoplakia is a pre-malignant lesion of the oral mucosa. The aim of this study is to compare the curative effects of photodynamic therapy and cryotherapy in the treatment of oral leukoplakia. The first group, treated by photodynamic therapy (δ-aminolevulinic acid (ALA), 630-635 nm wavelength), consisted of 48 patients suffering from leukoplakia. The second group consisted of 37 patients treated using cryotherapy. Analyses and comparisons of the complete responses, recurrences, numbers of procedures and adverse effects after both PDT and cryotherapy were obtained. In the first group, a complete response was obtained in 35 patients (72.9%), with thirteen recurrences observed (27.1%) over a six-month period. In the second group, a complete response was obtained in 33 patients (89.2%), and recurrence was observed in nine patients (24.3%). Photodynamic therapy and cryotherapy appear to be comparative methods of treatment that may both serve as alternatives for the traditional surgical treatment of oral leukoplakia. The advantages of PDT are connected with minimally invasive and localized character of the treatment and with not damage of collagenous tissue structures, therefore normal cells will repopulate these arrangements. PDT is more convenient for patients, less painful, and more esthetic.

Photodynamic therapy in treatment of cutaneous and choroidal melanoma

Melanoma is a malignant, the most aggressive and dreaded skin cancer. This form of cancer arises from melanocytes and may grow rapidly and metastasize. Melanoma predominantly occurs in skin, but could also be found in the mouth, iris and retina of the eye. Melanoma is the most dangerous form of skin cancer, with a steeply rising incidence and a poor prognosis in its advanced stages. It is highly resistant to traditional chemotherapy and radiotherapy, although modern biological therapies are showing some promise. Photodynamic therapy (PDT), as a novel effective modality of the treatment of skin cancers, opens up new possibilities in melanoma treatment also. Many experimental photodynamic therapy studies were performed. The results of many experiments indicate that that photodynamic therapy may be a promising tool for adjuvant treatment in advanced melanoma.

Photodynamic therapy in colorectal cancer treatment: the state of the art in clinical trials.

BACKGROUND Photodynamic therapy (PDT) is used in many different oncologic fields. Also in gastroenterology, where have been a few attempts to treat both the premalignant lesion and advanced colorectal cancer. This review aims to give a general overview of the PDT application to colorectal cancer in the field of clinical trials to emphasize its curative, and insufficiently exploited potential. MATERIALS AND METHODS Literature on PDT for colorectal cancer with the following medical subject headings search terms: colorectal cancer, photodynamic therapy, clinical trials was reviewed. The articles were selected by their relevance to the topic. RESULTS There are many positive and promising trial results from I to II/III phase for the use of PDT in colorectal cancer both in less advanced tumors as well as in the palliative therapy of advanced lesions. CONCLUDING REMARKS PDT seems to be a safe and a feasible treatment option for colorectal cancer. Theoretical assumptions confirmed by many results of preclinical studies taking into consideration an increasing number of analyzed clinical trials, should lead to the development of optimized standards by using PDT in colorectal cancer treatment.

Photodynamic therapy in colorectal cancer treatment—The state of the art in preclinical research

BACKGROUND Photodynamic therapy (PDT) is used in many different oncologic fields. Also in gastroenterology, where have been a few attempts to treat both the premalignant lesion and advanced colorectal cancer (CRC). This review aims to give a general overview of preclinical photodynamic studies related to CRC cells and animal studies of photodynamic effects related to CRC treatment to emphasize their potential in study of PDT mechanism, safety and efficiency to translate these results into clinical benefit in CRC treatment. MATERIALS AND METHOD Literature on in vitro preclinical photodynamic studies related to CRC cells and animal studies of photodynamic effects related to CRC treatment with the fallowing medical subject headings search terms: colorectal cancer, photodynamic therapy, photosensitizer(s), in vitro, cell culture(s), in vivo, animal experiment(s). The articles were selected by their relevance to the topic. RESULTS The majority of preclinical studies concerning possibility of PDT application in colon and rectal cancer is focused on phototoxic action of photosensitizers toward cultured colorectal tumor cells in vitro. The purposes of animal experiments are usually elucidation of mechanisms of observed photodynamic effects in scale of organism, estimation of PDT safety and efficiency and translation of these results into clinical benefit. CONCLUDING REMARKS In vitro photodynamic studies and animal experiments can be useful for studies of mechanisms and efficiency of photodynamic method as a start point on PDT clinical research. The primary disadvantage of in vitro experiments is a risk of over-interpretation of their results during extrapolation to the entire CRC.

ALA-induced photodynamic effect on vitality, apoptosis, and secretion of vascular endothelial growth factor (VEGF) by colon cancer cells in normoxic environment in vitro

BACKGROUND Cancer therapy is often based on combination of conventional methods of cancer treatment with immunotherapy. Photodynamic therapy (PDT) is one of the immunomodulating methods used in oncology. We examined how PDT influences the secretory activity of colon cancer cells in vitro, especially the secretion of vascular endothelial growth factor (VEGF) in aerobic conditions. METHODS We used two cancer cell lines with different malignancy potentials: a metastatic SW620 line and a non-metastatic SW480 line. In the first stage of the experiment, we exposed each cell line to three different concentrations of photosensitizers precursor: 5-aminolevulinic acid (ALA) and varying levels of light radiation, after which we assessed cell viability and apoptosis induction in these lines, using the MTT and LDH assays. Then, we determined the secretion of VEGF by these cells in aerobic conditions and under the ALA-PDT parameters at which cells presented the highest viability. RESULTS Photodynamic treatment with ALA did not influence on VEGF secretion by the non-metastatic SW480 cells, but caused a decrease in VEGF secretion by the metastatic SW 620 cell line by 29% (p<0.05). SW 620 cell line secreted more actively VEGF than the SW480 cells, both before and after photo dynamic therapy (p<0.05). CONCLUSION The outcome of this in vitro study presented a beneficial effect of ALA-PDT, resulting in a decrease of VEGF secretion in the more malignant SW620 cell lines. Further studies should be considered to confirm the clinical relevance of this finding.

Autofluorescence endoscopy with “real-time” digital image processing in differential diagnostics of selected benign and malignant lesions in the oesophagus

BACKGROUND Oesophageal papilloma and Barretts oesophagus are benign lesions known as risk factors of carcinoma in the oesophagus. Therefore, it is important to diagnose these early changes before neoplastic transformation. METHOD Autofluorescence endoscopy is a fast and non-invasive method of imaging of tissues based on the natural fluorescence of endogenous fluorophores. The aim of this study was to prove the diagnostic utility of autofluorescence endoscopy with digital image processing in histological diagnosis of endoscopic findings in the upper digestive tract, primarily in the imaging of oesophageal papilloma. RESULTS During the retrospective analysis of about 200 endoscopic procedures in the upper digestive tract, 67 cases of benign, precancerous or cancerous changes were found. White light endoscopy (WLE) image, single-channel (red or green) autofluorescence images, as well as green and red fluorescence intensities in two modal fluorescence image and red-to-green (R/G) ratio (Numerical Colour Value, NCV) were correlated with histopathologic results. The NCV analysis in autofluorescence imaging (AFI) showed increased R/G ratio in cancerous changes in 96% vs. 85% in WLE. Simultaneous analysis with digital image processing allowed us to diagnose suspicious tissue as cancerous in all of cases. Barretts metaplasia was confirmed in 90% vs. 79% (AFI vs. WLE), and 98% in imaging with digital image processing. In benign lesions, WLE allowed us to exclude tissue as malignant in 85%. Using autofluorescence endoscopy R/G ratio was increased in only 10% of benign changes causing the picture to be interpreted as suspicious, but when both methods were used together, 97.5% were cases excluded as malignancies. Mean R/G ratios were estimated to be 2.5 in cancers, 1.25 in Barretts metaplasia and 0.75 in benign changes and were statistically significant (p=0.04). CONCLUSION Autofluorescence imaging is a sensitive method to diagnose precancerous and cancerous early stages of the diseases located in oesophagus. Especially in two-modal imaging including white light endoscopy, autofluorescence imaging with digital image processing seems to be a useful modality of early diagnostics. Also in observation of papilloma changes, it facilitates differentiation between neoplastic and benign lesions and more accurate estimation of the risk of potential malignancy.

ALA-mediated photodynamic effect on apoptosis induction and secretion of macrophage migration inhibitory factor (MIF) and of monocyte chemotactic protein (MCP-1) by colon cancer cells in normoxia and in hypoxia-like conditions in vitro

BACKGROUND Photodynamic therapy (PDT) reveals immune modulatory effect. The aim of the study was to evaluate the influence of 5-aminolevulinic acid (ALA) mediated photodynamic effect on secretory activity (MIF, MCP-1) of colon cancer cells in vitro both in normoxia and in hypoxia-like conditions. METHODS Two colon cancer cell lines differing in malignancy potential: SW480 (lower grade) and SW620 (higher grade) were used. MCP-1 and MIF concentrations in supernatants of cells cultures after pretreatment with ALA at concentrations of 500, 1000 and 1500μM and irradiation with incoherent light (λ=600-720nm) at fluences of 10, 30 and 60J/cm(2), using Bio-Plex ProTM Assay kit and Bio-Plex Suspension Array System apparatus, were measured. RESULTS The SW620 cells were more susceptible to ALA-mediated phototoxic effect than SW480 one, however this effect may be partly abolished in hypoxia-like condition. In the case of SW480 cell line, no influence of hypoxia-like conditions on cell susceptibility to ALA-mediated photodynamic effect was found. The MIF concentration increased, contrary to MCP-1 one which decreased after ALA-mediated photodynamic action in both cell lines. No difference between cytokines concentration in supernatant from cells cultures in normoxia or hypoxia-like conditions was observed. CONCLUSIONS Detected reduction in MCP-1 secretion appears to be advantage because of tumors growth limiting but an increase in the secretion of MIF, which is responsible for stimulation of tumor cells proliferation, is an unfavorable effect. These results may be explained by the fact that the used cancer cell lines differ from each other in cancer stage.

The role of fluorescence diagnosis in clinical practice

Fluorescence diagnosis is a fast, easy, noninvasive, selective, and sensitive diagnostic tool for estimation of treatment results in oncology. In clinical practice the use of photodynamic diagnosis is focused on five targets: detection for prevention of malignant transformation precancerous changes, detection of neoplasmatic tissue in the early stages for fast removal, prevention of expansion and detection of recurrence of the cancer, monitoring therapy, and the possibility of excluding neoplasmatic disease. In this article, selected applications of fluorescence diagnosis at the Center for Laser Diagnostics and Therapy in Bytom, Poland, for each of these targets are presented.

Solitary rectal ulcer syndrome—The role of autofluorescence colonoscopy

BACKGROUND Solitary rectal ulcer syndrome (SRUS) is a rare disorder of the rectum but it causes differential diagnosis problems. AIM To determine the potential use of autofluorescence colonoscopy (AFC) in diagnosis of SRUS. MATERIAL AND METHODS We performed 1618 colonoscopies. After the medical history was taken white light colonoscopy was performed. The tissue samples were taken for routine pathological examination. When SRUS was histopathologically confirmed AFC was performed by means of OncoLIFE. The mean time lapse between the two colonoscopies was 4 weeks. During AFC numerical colour value (NCV) of autofluorescence of SRUS lesions was noted. RESULTS During 1618 colonoscopies six persons were diagnosed as having solitary rectal ulcer syndrome (0.37%). The mean age was 43.8 years. There were two men and four women. In our material the endoscopic spectrum was: three (50%) polypoid lesions, two (33.33%) flat ulcers and one case (16.66%) of isolated, local erythema with hyperemia. We did not observe decrease of fluorescence in case of polipoid and flat ulcer lesions (NCV 0.39-0.67; mean 0.525) and little decrease of fluorescence in case of erythema lesion (NCV -0.94). CONCLUSION Autofluorescence colonoscopy by means of OncoLIFE appears to be a promising approach in diagnosis of SRUS. The estimation of numerical colour value which is an objective test of autofluorescence intensity, facilitates the differential diagnosis and helps to chose the right management of SRUS.

The possibilities of improvement in the sensitivity of cancer fluorescence diagnostics by computer image processing

Background: Fluorescence diagnostics uses the ability of tissues to fluoresce after exposition to a specific wavelength of light. The change in fluorescence between normal and progression to cancer allows to see early cancer and precancerous lesions often missed by white light. Aim: To improve by computer image processing the sensitivity of fluorescence images obtained during examination of skin, oral cavity, vulva and cervix lesions, during endoscopy, cystoscopy and bronchoscopy using Xillix ONCOLIFE. Methods: Function of image f(x,y):R2 → R3 was transformed from original color space RGB to space in which vector of 46 values refers to every point labeled by defined xy-coordinates- f(x,y):R2 → R46. By means of Fisher discriminator vector of attributes of concrete point analalyzed in the image was reduced according to two defined classes defined as pathologic areas (foreground) and healthy areas (background). As a result the highest four fishers coefficients allowing the greatest separation between points of pathologic (foreground) and healthy (background) areas were chosen. In this way new function f(x,y):R2 → R4 was created in which point x,y corresponds with vector Y, H, a*, c2. In the second step using Gaussian Mixtures and Expectation-Maximisation appropriate classificator was constructed. This classificator enables determination of probability that the selected pixel of analyzed image is a pathologically changed point (foreground) or healthy one (background). Obtained map of probability distribution was presented by means of pseudocolors. Results: Image processing techniques improve the sensitivity, quality and sharpness of original fluorescence images. Conclusion: Computer image processing enables better visualization of suspected areas examined by means of fluorescence diagnostics.