Photodynamic treatment of neoplastic lesions of the gastrointestinal tract. Recent advances in techniques and results

Photodynamic Therapy and Immunological View in Gastrointestinal Tumors

Gastrointestinal cancers are a specific group of oncological diseases in which the location and nature of growth are of key importance for clinical symptoms and prognosis. At the same time, as research shows, they pose a serious threat to a patient's life, especially at an advanced stage of development. The type of therapy used depends on the anatomical location of the cancer, its type, and the degree of progression. One of the modern forms of therapy used to treat gastrointestinal cancers is PDT, which has been approved for the treatment of esophageal cancer in the United States. Despite the increasingly rapid clinical use of this treatment method, the exact immunological mechanisms it induces in cancer cells has not yet been fully elucidated. This article presents a review of the current understanding of the mode of action of photodynamic therapy on cells of various gastrointestinal cancers with an emphasis on colorectal cancer. The types of cell death induced by PDT include apoptosis, necrosis, and pyroptosis. Anticancer effects are also a result of the destruction of tumor vasculature and activation of the immune system. Many reports exist that concern the mechanism of apoptosis induction, of which the mitochondrial pathway is most often emphasized. Photodynamic therapy may also have a beneficial effect on such aspects of cancer as the ability to develop metastases or contribute to reducing resistance to known pharmacological agents.

PDT for Gastric Cancer - the view from China

The incidence rate and mortality of gastric cancer remain elevated. Traditionally, surgical treatment (including endoscopic surgery and traditional surgery), chemotherapy, targeted therapy, and immunotherapy were used for the treatment of gastric cancer. Although the emergence of targeted therapy and immunotherapy can effectively prolong the survival of some patients with gastric cancer and improve the quality of life of patients after chemotherapy or surgery, the overall survival rate of gastric cancer has not been significantly improved. Photodynamic therapy is a local photochemical therapy with the advantages of high safety, few adverse reactions, and repeatability, although it may cause some toxic reactions. There are some differences between East and West in the treatment of gastric cancer with PDT, and most earlier studies concentrated on using PDT alone. However, some studies have indicated that PDT may enhance the efficacy of chemotherapy and other medications. This paper summarizes the study on the use of PDT and its combination therapy in gastric cancer, which is anticipated to offer novel thoughts for the treatment of gastric cancer.

Successful treatment of penile condyloma acuminata accompanied with lichen planus with photodynamic therapy

Condyloma acuminata and lichen planus are different cutaneous diseases with disparate etiologies. Simultaneous appearance of two diseases in the same area is rare. This report aims to share the clinical and pathological features of a rare case; introduce an effective and safe therapy of it so as to broaden the therapeutic spectrum of Photodynamic Therapy (PDT) indications.

The Role of Free Radicals in the Photodynamic Treatment of Fibrotic Skin Diseases

The first derivatives of gelatin and type I collagen fluorescence spectra were characterized in order to describe the effect of free radicals on pyridinoline (PYD) cross-links. The different gas saturation conditions were used to investigate the effect of different free radicals. An analysis of first derivative fluorescence spectra suggests that PYD cross-link fluorescence emission is composed of three peaks in gelatin, but only two in type I collagen. The PYD cross-link was photo-degraded more than other gases in the presence of O2. This suggests that the singlet oxygen ((1)O2) plays a key role when using photodynamic therapy to treat skin fibrosis disease with Hypocrellin B (HB).

Different optical properties between human hepatocellular carcinoma tissues and non-tumorous hepatic tissues in vitro

There has been an ongoing search for clinically acceptable methods for the accurate, efficient and simple diagnosis and prognosis of hepatocellular carcinoma (HCC). Optical spectroscopy is a technique with potential clinical applications to diagnose cancer diseases. The purpose of this study was to obtain the optical properties of HCC tissues and non-tumorous hepatic tissues and identify the difference between them. A total of 55 tissue samples (HCC tissue, n=38; non-tumorous hepatic tissue, n=17) were surgically resected from patients with HCC. The optical parameters were measured in 10-nm steps using single-integrating-sphere system in the wavelength range of 400 to 1800 nm. It was found that the optical properties and their differences varied with the wavelength for the HCC tissue and the non-tumorous hepatic tissue in the entire wavelength range of research. The absorption coefficient of the HCC tissue (1.48±0.99, 1.46±0.88, 0.86±0.61, 2.15±0.53, 0.54±0.10, 0.79±0.15 mm(-1)) was significantly lower than that of the non-tumorous hepatic tissue (2.79±1.73, 3.13±1.47, 3.06±2.79, 2.57±0.55, 0.62±0.10, 0.93±0.16 mm(-1)) at wavelengths of 400, 410, 450, 1450, 1660 and 1800 nm, respectively (P<0.05). The reduced scattering coefficient of HCC tissue (5.28±1.70, 4.91±1.54, 1.26±0.35 mm(-1)) and non-tumorous hepatic tissue (8.14±3.70, 9.27±3.08, 2.55±0.57 mm(-1)) was significantly different at 460, 500 and 1800 nm respectively (P<0.05). These results show different pathologic liver tissues have different optical properties. It provides a better understanding of the relationship between optical parameters and physiological characteristics in human liver tissues. And it would be very useful for developing a non-invasive, real-time, simple and efficient way for medical management of HCC in the future.

Advances in photodynamic therapy for gastrointestinal tumors and its propect

This paper reviews the photodynamic therapy for gastrointestinal tumors and its mechanisms, and describes the authors' experience with it. It is feasible and reasonable to use photodynamic therapy for gastrointestinal tumors. It is not in contradiction with PDT and traditional surgical treatment, chemotherapy, radiation and immune therapy, etc. The main mechanisms of photodynamic therapy for gastrointestinal tumors are to damage tumor microvasculature, induce cancer cell apoptosis, injure cancer cell membrane, and trigger immune reactions.

Measuring Subjective Side Effects and Symptoms in Palliative Photodynamic Therapy

PURPOSE/OBJECTIVES

To evaluate the reliability and validity of the Photodynamic Therapy Side Effects and Symptoms Scale (PSES) and to begin to describe patient-reported outcomes of photodynamic therapy (PDT).

DESIGN

Repeated-measures instrument validation. The PSES uses a 10-point numeric scale to evaluate side effects or symptom trouble or burden on 13 items.

SETTING

A Pacific Northwest community hospital.

SAMPLE

14 patients with end-stage lung or esophageal cancer undergoing palliative PDT.

METHODS

Participants completed five PSES surveys (i.e., at baseline and once a week for four weeks after PDT). Weekly phone calls were made to assess functional status, operationalized as Karnofsky Performance Status.

MAIN RESEARCH VARIABLES

Symptoms and functional status.

FINDINGS

The PSES possessed acceptable internal consistency reliability and concurrent validity. Functional status declined in the first week after PDT, concurrent with an increase in side-effect and symptom burden. Photosensitivity became more burdensome over time but was never extremely burdensome.

CONCLUSIONS

The feasibility of measuring a diverse set of side effects and symptoms in end-stage cancer with a single-page, large-type instrument essentially was supported. The study provided preliminary information about side effects and symptoms in patients undergoing palliative PDT.

IMPLICATIONS FOR NURSING

Nurses often are called on to provide information to patients considering various treatment options. This study offers the first data on patient-reported outcomes of palliative PDT that clinicians can use to help in answering inquiries. The design of the PSES may be replicated by researchers working with other populations with end-stage disease to reduce respondent burden and decrease attrition.

Optical properties of adenocarcinoma and squamous cell carcinoma of the gastroesophageal junction

Photodynamic therapy (PDT) is an alternative to radical surgical resection for T1a or nonresectable carcinomas of the gastroesophageal junction. Besides the concentration of the photosensitizer, the light distribution in tissue is responsible for tumor destruction. For this reason, knowledge about the behavior of light in healthy and dysplastic tissue is of great interest for careful irradiation scheduling. The aim of this study is to determine the optical parameters (OP) of healthy and carcinomatous tissue of the gastroesophageal junction in vitro to provide reproducible parameters for optimal dosimetry when applying PDT. A total of 36 tissue samples [adenocarcinoma tissue (n=21), squamous cell tissue (n=15)] are obtained from patients with carcinomas of the gastroesophageal junction. The optical parameters are measured in 10-nm steps using new integrating sphere spectrometers in the PDT-relevant wavelength range of 300 to 1140 nm and evaluated by inverse Monte-Carlo simulation. Additional examinations are done in healthy tissue from the surgical safety margin. In the wavelength range of frequently applied photosensitizers at 330, 630, and 650 nm, the absorption coefficient in tumor tissue (adenocarcinoma 1.22, 0.16, and 0.15 mm(-1); squamous cell carcinoma 1.48, 0.13, and 0.11 mm(-1)) is significantly lower than in healthy tissue (stomach 3.34, 0.26, and 0.20 mm(-1); esophagus 2.47, 0.21, and 0.18 mm(-1)). The scattering coefficient of all tissues decreases continuously with increasing wavelength (adenocarcinoma 22.8, 12.99, and 12.52 mm(-1); squamous cell carcinoma 19.44, 9.35, and 8.98 mm(-1); stomach 20.55, 13.96, and 13.94 mm(-1); esophagus 20.34, 12.56, and 12.22 mm(-1). All tissues show an anisotropy factor between 0.80 and 0.94 over the entire spectrum. The maximum optical penetration depth for all tissues is achieved in the range of 800 to 1100 nm. At the wavelength range of 330, 630, and 650 nm, the optical penetration depth is significantly higher in carcinoma tissue (adenocarcinoma 0.27, 1.54, and 1.66 mm; squamous cell carcinoma 0.23, 1.71, and 1.84 mm) than in healthy tissue (stomach 0.16, 1.10, and 1.26 mm; esophagus 0.17, 1.47, and 1.65 mm; p<0.05). Above 1000 nm, a higher absorption coefficient of tumor tissue results in a lower optical penetration depth than in healthy tissue (p<0.05). The higher absorption and scattering of the tumor tissue in the wavelength range of available photosensitizer is associated with a low optical penetration depth. This necessitates higher energy doses and long application times or repeated applications to effectively treat large tumor volumes. Photosensitizers optimized for larger wavelength range need to be developed to increase the efficacy of PDT.

Photodynamic Therapy for Urological Malignancies: Past to Current Approaches

PURPOSE

Modern PDT for urological tumors is a potentially selective approach in which in situ photosensitization by a nontoxic drug, locally activated by light, generates cytotoxic reactive oxygen species, causing cell death. While urological clinical experience with PDT is largely limited to treatment for superficial bladder cancer, the advent of novel photosensitizers and technologies for treatment planning, light delivery and dosimetry, PDT for prostate and other urological cancers appears increasingly realistic.

MATERIALS AND METHODS

We reviewed the current literature on PDT for urological tumors, in addition to recent emerging data from our laboratory and elsewhere.

RESULTS

Remarkable progress has been made in the field of photochemistry and photobiology. Together with improved optical delivery and imaging systems PDT holds promise as an alternative, minimally invasive and potentially curative treatment for localized solid tumors as well as for palliative treatment for isolated, clinically problematic metastases.

CONCLUSIONS

Current experience with photodynamic therapy using contemporary photosensitizing agents and light sources is mainly restricted to in vivo experimental models and early phase clinical trails. However, ongoing preclinical work and clinical trials indicate that safer and effective PDT treatments in uro-oncology are imminent.

Small Bowel Adenocarcinoma: A Rare but Aggressive Disease

Unlike the colon and rectum, the small intestine is associated with a very low rate of tumor occurrence. Adenocarcinomas represent the most frequent of these rare digestive tumors and are often fatal as a result of tardy diagnosis. Regardless of the stage, surgery usually remains the cornerstone of small bowel adenocarcinoma therapy. Because of the rarity of the disease, very few significant clinical trials have identified any efficient nonsurgical treatment; however, recent data indicate these tumors might be sensitive to chemotherapy alone or in association with radiation therapy. Conversely, a great deal of progress has been achieved in diagnosis of the tumor, whether by adaptation of existing techniques or development of new ones. We reviewed the clinical aspects of this rare but aggressive disease, focusing on new diagnostic procedures as well as on recent advances in their therapeutic management.

Photodynamic therapy in Barrett's esophagus

Photodynamic therapy (PDT) was one of the earliest ablative techniques applied to Barrett's esophagus. The rationale for this use was the ability to treat large amounts of esophageal mucosa in a single rapid application. Additionally, PDT has the ability to treat early carcinoma and dysplastic tissue. Because a small carcinoma in dysplastic Barrett's esophagus cannot not be excluded, PDT therapy is a reasonable treatment in this setting. The treatment involves the use of a light and drug combination that must be administered with close attention to dosimetry, since tissue effects of the therapy are delayed and cannot be observed at the time of treatment. Drug administration of sodium porfimer should precede photoradiation by 48 hours. Overall results with this treatment have been good. Case series have established a success rate of 88% to 100% in elimination of high-grade dysplasia. The only randomized multi-center prospective trial in the treatment of Barrett's esophagus with high-grade dysplasia has established that the treatment eliminates high-grade dysplasia better than administration of proton pump inhibitors alone. Unfortunately, there are significant adverse events, including cutaneous photosensitivity, odynophagia, stricture formation, and lack of response.