Photodynamic destruction of high grade dysplasia and early carcinoma of the esophagus after the oral administration of 5-aminolevulinic acid

5-ALA Photodynamic Ablation of Fibroblsatic Sift-Tissues Tumors

BACKGROUND

Fibroblastic soft-tissue tumors share enzymatic anomalies that result in excessive intracellular conversion of 5-aminolevulinic acid (5-ALA) to protoporphyrin IX, a photosensitizer which induces cellular apoptosis upon exposure to visible red light at a wavelength of 635 nm. We hypothesized that red light illumination of the surgical bed remaining after resection of fibroblastic tumors will result in destruction of microscopic tumor residua and may decrease the likelihood of local tumor recurrence.

METHODS

Twenty-four patients with desmoid tumors, solitary fibrous tumors (SFT), and dermatofibrosarcoma protuberans (DFSP) received oral 5-ALA prior to resection of their tumors. Following tumor resection, the exposed surgical bed was illuminated with red light at a wave length of 635 nm at a dose of 150J/cm² for 33 minutes.

RESULTS

Treatment with 5-ALA was associated with minor side effects that included nausea and transient elevation of transaminases. Local tumor recurrence was detected in 1 of the 10 patients with desmoid tumors who had not undergone any previous surgery, none in the 6 patients who had SFT and 1 of the 5 patients who had DFSP.

CONCLUSIONS

5-ALA photodynamic therapy of fibroblastic soft-tissue tumors may result in decreased likelihood of local tumor recurrence. It is associated with minimal side effects and should be considered as adjuvant to tumor resection in these cases.

Randomized comparison of three palliative regimens including brachytherapy, photodynamic therapy, and APC in patients with malignant dysphagia (CONSORT 1a) (Revised II)

OBJECTIVES

Because most esophageal cancers are diagnosed at an advanced stage, a majority of patients require palliative dysphagia treatment. Dysphagia severity and the need for repeated re-canalization procedures significantly affect patients' quality of life (QoL). The aim of this study was to establish whether combining argon plasma coagulation (APC) of the neoplastic esophageal tissue with another re-canalization method results in a longer dysphagia-free period compared with APC alone.

METHODS

We conducted a randomized trial in 93 patients with malignant dysphagia. Patients were followed until death. We compared three regimens of esophageal re-canalization; APC combined with high dose rate (HDR) brachytherapy, APC combined with photodynamic therapy (PDT), and APC alone. The primary outcome measure was the dysphagia-free period following randomization. Secondary measures were survival, QoL, treatment-associated complications, and treatment tolerance. A per-protocol analysis was carried out.

RESULTS

The time to first dysphagia recurrence was significantly different between each combination treatment group and the control group (overall test: P=0.006; HDR vs. control, log-rank P=0.002, PDT vs. control, log-rank P=0.036), but not different between the combination groups (HDR vs. PDT, log-rank P=0.36). The median time to first dysphagia recurrence was 88, 59, and 35 days in the HDR, PDT, and control groups, respectively. There was no difference in overall survival between the study groups (P=0.27). No deaths, perforations, hemorrhages, or fistula formations were attributed to treatment. The only major complication was fever, occurring in three PDT patients. Minor complications were observed significantly more often in the combination treatment groups and included pain in both groups, transient dysphagia worsening, and skin sensitivity in the PDT group. The QoL 30 days after treatment in the HDR group was significantly better than in the other groups.

CONCLUSIONS

In patients with inoperable esophageal cancer, palliative combination treatment of dysphagia with APC and HDR or PDT was significantly more efficient than APC alone, and was safe and well tolerated. APC combined with HDR resulted in fewer complications and better QoL than APC with PDT or APC alone (CONSORT 1b).

The safety and effectiveness of endoscopic and non-endoscopic approaches to the management of early esophageal cancer: a systematic review

INTRODUCTION

Traditionally, management of early cancer (stages 0-IIA) has comprised esophagectomy, either alone or in combination with chemotherapy and/or radiotherapy. Recent efforts to improve outcomes and minimize side-effects have focussed on minimally invasive, endoscopic treatments that remove lesions while sparing healthy tissue. This review assesses their safety and efficacy/effectiveness relative to traditional, non-endoscopic treatments for early esophageal cancer.

METHODS

A systematic review of peer-reviewed studies was performed using Cochrane guidelines. Bibliographic databases searched to identify relevant English language studies published in the last 3 years included: PubMed (i.e., MEDLINE and additional sources), EMBASE, CINAHL, The Cochrane Library, the UK Centre for Reviews and Dissemination (NHS EED, DARE and HTA) databases, EconLit and Web of Science. Web sites of professional associations, relevant cancer organizations, clinical practice guidelines, and clinical trials were also searched. Two independent reviewers selected, critically appraised, and extracted information from studies.

RESULTS

The review included 75 studies spanning 3124 patients and 10 forms of treatment. Most studies were of short term duration and non-comparative. Adverse events reported across studies of endoscopic techniques were similar and less significant compared to those in the studies of non-endoscopic techniques. Complete response rates were slightly lower for photodynamic therapy (PDT) relative to the other endoscopic techniques, possibly due to differences in patient populations across studies. No studies compared overall or cause-specific survival in patients who received endoscopic treatments vs. those who received non-endoscopic treatments.

DISCUSSION

Based on findings from this review, there is no single "best practice" approach to the treatment of early esophageal cancer.

The role of photodynamic therapy in the esophagus

Photodynamic therapy (PDT) is a drug and device therapy using photosensitizer drugs activated by laser light for mucosal ablation. Porfimer sodium PDT has been used extensively with proven long-term efficacy and durability for the ablation of Barrett esophagus and high-grade dysplasia. and early esophageal adenocarcinoma. However, continued use is hampered by an associated stricture risk and prolonged photosensitivity (4-6 weeks). Promising single-center European studies using other forms of PDT, such as aminolevulinic acid PDT, have not been replicated elsewhere, limiting the widespread use of other forms of PDT. Future use of PDT in esophageal disease depends on the development of improved dosimetry and patient selection to optimize treatment outcomes, while minimizing adverse events and complications.

Successful balloon-based radiofrequency ablation of a widespread early squamous cell carcinoma and high-grade dysplasia of the esophagus: a case report

BACKGROUND

For selected patients with high-grade dysplasia (HGD) and/or early esophageal squamous cell cancer (ESCC), endoscopic therapy represents a nonsurgical treatment option. For widespread lesions, however, current endoscopic treatment modalities (eg, endoscopic resection, argon plasma coagulation, photodynamic therapy) are associated with considerable drawbacks, of which esophageal stricturing is the most significant. Balloon-based radiofrequency (RF) ablation (HALO System) is a promising technology for endoscopic treatment of Barrett's esophagus, and may also play a role in treating widespread HGD and early ESCC.

OBJECTIVE

We describe a case report of balloon-based RF ablation for HGD and early ESCC.

DESIGN

Case report.

SETTING

Tertiary care institution, Academic Medical Center, Amsterdam, The Netherlands.

PATIENT

A 66-year-old male with a 35-mm large, flat-type ESCC with surrounding HGD.

INTERVENTION

Balloon-based RF ablation (HALO System).

MAIN OUTCOME MEASUREMENTS

Endoscopic and histological eradication of HGD and ESCC, and adverse events.

RESULTS

RF ablation resulted in complete endoscopic and histological eradication of HGD and ESCC without adverse events such as dysphagia or esophageal narrowing.

LIMITATIONS

Single patient report, limited follow-up.

CONCLUSIONS

This is the first report of balloon-based RF ablation for esophageal HGD and early ESCC. The treatment resulted in complete eradication of a 35-mm flat ESCC with no adverse events. This suggests that this ablation technique deserves further study for the management of widespread HGD or flat-type ESCC.

Endoscopic approaches to Barrett's oesophagus with high-grade dysplasia/early mucosal cancer

This chapter will review the endoscopic approaches to the management of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer. Factors to consider when evaluating patients for endoscopic management are detailed. Ablation and resection methods for eradication of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer are reviewed. Strategies for combining therapies to achieve safe and effective eradication are discussed. Recommendations for complete eradication of all Barrett's mucosa and follow-up considerations are put forward.

Silencing of human ferrochelatase causes abundant protoporphyrin-IX accumulation in colon cancer

Hemes and heme proteins are vital components of essentially every cell of virtually every eukaryote organism. Previously, we demonstrated accumulation of the heme precursor protoporphyrin-IX (PpIX) in gastrointestinal tumor tissues. To elucidate the mechanisms of PpIX accumulation by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we studied expression of the relevant enzymes of the heme synthetic pathway. Here, we describe a significant down-regulation of ferrochelatase (FECH) mRNA expression in gastric, colonic, and rectal carcinomas. Accordingly, in an in vitro model of several carcinoma cell lines, ferrochelatase down-regulation and loss of enzymatic activity corresponded with an enhanced PpIX-dependent fluorescence. Direct detection of PpIX in minute amounts was achieved by a specifically developed pulsed solid-state laser dual delay fluorimetry setup. Silencing of FECH using small interfering RNA (siRNA) technology led to a maximum 50-fold increased PpIX accumulation, imageable by a specifically adapted two-photon microscopy unit. Our results show that in malignant tissue a transcriptional down-regulation of FECH occurs, which causes endogenous PpIX accumulation. Furthermore, accumulation of intracellular PpIX because of FECH siRNA silencing provides a small-molecule-based approach to molecular imaging and molecular therapy.

Massive apoptotic cell death of human glioma cells via a mitochondrial pathway following 5-aminolevulinic acid-mediated photodynamic therapy

The basic mechanism of cell death induced by 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) (ALA-PDT) in glioma cells has not been fully elucidated. In this study, the details of the cell death mechanism induced by ALA-PDT were investigated in three human glioma cell lines (U251MG, U87MG, and U118MG) in vitro. To evaluate the manner of accumulation of protoporphyrin IX (PpIX), intracellular PpIX contents were measured by flow cytometry after incubation with 5-ALA. To analyze the mechanism of cell death, U251MG cells were assayed by the terminal deoxynucleotidyl transferase-mediated dUTP-FITC nick end-labeling (TUNEL) method, and the caspase activity was measured after ALA-PDT. Furthermore, the mitochondrial membrane potential (MMP) and the release of mitochondrial cytochrome c were determined. PpIX fluorescence reached a plateau 4 h after exposure to 5-ALA. The proportion of dead cells increased with increases in the dosage of light. These cells were confirmed by TUNEL staining to be apoptotic. Increases in the activity of both caspase-3 and -9, a decrease in MMP, and a marked increase in cytochrome c in the cytosolic fraction were found after cells were subjected to PDT. These results indicate that a dysfunction of MMP is followed by mitochondrial cytochrome c release, which triggers apoptosis through a mitochondrial pathway. ALA-PDT induces massive apoptosis due to the direct activation of a mitochondrial pathway, which is resistant to many anti-apoptotic processes, in human glioma cells. This finding implies that ALA-PDT is a promising therapy for the treatment of apoptosis-reluctant tumors such as malignant gliomas.

[Mucosectomy as sufficient therapy for early squamous cell]

Squamous cell carcinoma of the esophagus can be treated endoscopically under certain conditions. A carcinoma (T1a) limited to the mucosa with a low infiltration depth (m1-m2) and limited extent (< or =2 cm) can be removed by electrical snare with no risk of lymph node metastasis. Due to the increased risk of lymphatic spread, deeply infiltrating submucosal tumours (sm2-sm3) must be treated by surgical resection. Endoscopic resection (mucosectomy) is performed by electric snare and the cap method, additionally with APC coagulation or photodynamic therapy. Multifocal tumour growth and incomplete resection are both risk factors for local recurrence. If the strict conditions for endoscopic resection are fulfilled, the 5-year survival time of these patients with early cancer is no different from that of the population as a whole.

Endoscopic treatment of high-grade intraepithelial neoplasia and early cancer in Barrett oesophagus

In the last 5 years, endoscopic therapy for high-grade intraepithelial neoplasia (HGIN) and early cancer (EC) in Barrett oesophagus has emerged as an effective and safe alternative to surgery. Adequate work-up of patients includes histopathological review of the initial biopsies, a high-resolution endoscopy with four-quadrant random biopsies every 1cm of Barrett mucosa and staging with endoscopic ultrasonography. Endoscopic resection (ER) forms the mainstay of the endoscopic treatment since it provides large tissue specimens for optimal histopathological evaluation. The ER-cap technique with submucosal injection and the 'suck-band-and cut' method are the resection methods most widely used in Barrett oesophagus patients. ER monotherapy for HGIN or EC in Barrett oesophagus is associated with recurrent lesions in up to 30% of treated patients. ER may be combined with ablative techniques such as photodynamic therapy (PDT) to treat all of the mucosa at risk for neoplastic progression. Unlike ER, PDT lacks histopathological correlation and residual Barrett mucosa may remain after treatment or may be hidden underneath the neosquamous epithelium. Management of Barrett oesophagus patients with HGIN or EC should be performed in centres with multi-disciplinary experience in this field and future studies should focus on development of ER techniques that allow radical resection of the whole Barrett segment.

Emerging endoscopic techniques in oncology

New techniques have expanded the role of endoscopy in the diagnosis, staging, therapy, and palliation of malignancies. Three major areas of emerging technologies--endoscopic ultrasound (EUS), luminal stent technology, and photodynamic therapy (PDT)--are discussed in this article. Although EUS and PDT have been used for more than two decades, they have only recently emerged as established integral methods in the armamentarium of the gastrointestinal endoscopist.

Endoscopic ultrasound for luminal malignancies

Luminal gastrointestinal (GI) tract cancers are responsible for substantial morbidity and mortality. Since the first pairing of ultrasonography with endoscopy in 1980, technologic advances and the increased availability of trained endosonographers have propelled endoscopic ultrasonography (EUS) to the forefront of luminal GI cancer staging. In this article we discuss the role of EUS for evaluating luminal GI cancers.

Selected Laser-based Therapies in Otolaryngology

This article has discussed selected applications of laser therapies in otolaryngology. Lasers are the treatment of choice for PWS lesions, but new advances are needed to achieve complete blanching in the majority of cases. Noninvasive in vivo imaging and laser therapy coupled with PDT are two areas showing promise to improve outcome. PDT has the potential to offer new, cost-effective treatment options, and possibly cure, to cancer patients who are not candidates for traditional surgery, chemotherapy, and radiotherapy.

Present status of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

GOALS

Review recent developments in Barrett's dysplasia including regulatory approval of porfimer sodium photodynamic therapy.

BACKGROUND

Barrett's esophagus is thought to be the result of long-standing gastroesophageal reflux disease and is known to be the most important risk factor for the development of esophageal adenocarcinoma. The natural history of Barrett's esophagus is not well known, but the annual incidence of invasive adenocarcinoma is estimated to be 0.5% (reported range, 0.2%-2.0%). This represents an increased risk for esophageal cancer of 30 to 60 times higher than normal subjects. As for colorectal cancer, malignant degeneration is Barrett's esophagus is thought to occur through a continuum of histologic stages: metaplasia, dysplasia and neoplasia. Barrett's high-grade dysplasia (formerly referred to as carcinoma in situ) is the histologic stage of disease that immediately precedes the development of invasive carcinoma.

CONCLUSIONS

Previously, Barrett's high-grade dysplasia patients were routinely referred for esophageal resection surgery based upon the assumption of inevitable progression to cancer, the high rate of undiagnosed synchronous cancers, and few treatment alternatives. Important developments in Barrett's high-grade dysplasia include recent publications regarding the natural history of Barrett's high-grade dysplasia and the regulatory approval for endoscopic ablation therapy using porfimer sodium photodynamic therapy (Photofrin PDT).

Cost-effectiveness of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

BACKGROUND

Photodynamic therapy appears to be effective in ablating high-grade dysplasia in Barrett's esophagus. Our aim was to identify the most effective and cost-effective strategy for managing high-grade dysplasia in Barrett's esophagus without associated endoscopically visible abnormalities.

METHODS

By using decision analysis, the lifetime costs and benefits of 4 strategies for which long-term data exist were estimated by us: esophagectomy, endoscopic surveillance, photodynamic therapy, followed by esophagectomy for residual high-grade dysplasia; and photodynamic therapy followed by endoscopic surveillance for residual high-grade dysplasia. It was assumed by us that there was a 30% prevalence of cancer in high-grade dysplasia patients and a 77% efficacy of photodynamic therapy for high-grade dysplasia and early cancer.

RESULTS

Esophagectomy cost 24,045 dollars, with life expectancy of 11.82 quality-adjusted life years. In comparison, photodynamic therapy followed by surveillance for residual high-grade dysplasia was the most effective strategy, with a quality-adjusted life expectancy of 12.31 quality-adjusted life years, but it also incurred the greatest lifetime cost (47,310 dollars) for an incremental cost-effectiveness of 47,410 dollars/quality-adjusted life years. The results were sensitive to post-surgical quality of life and survival, and to cancer prevalence if photodynamic therapy efficacy for cancer was less than 50%.

CONCLUSIONS

Photodynamic therapy followed by endoscopic surveillance for residual high-grade dysplasia appears to be cost effective compared with esophagectomy for patients diagnosed with high-grade dysplasia in Barrett's esophagus. Clinical trials directly comparing these strategies are warranted.

Endoscopic resection of superficial esophageal squamous-cell carcinomas: Western experience

OBJECTIVES

Endoscopic resection of esophageal squamous-cell neoplasia with curative intent appears to be an alternative treatment to radical surgery when the malignant neoplasia is intraepithelial or limited to the mucosal layer, since the risk for lymph-node metastases is very low. In contrast to Japan, there has so far been only limited experience in Europe and the United States with endoscopic resection in such cases. In the present observational study, we report on the largest prospective series so far in Western countries of patients with early squamous-cell cancer or carcinoma in situ, who were treated using endoscopic resection therapy.

METHODS

Between December 1997 and November 2001, 115 patients with a suspicion of early squamous cancer were referred for local endoscopic therapy. A total of 39 patients (mean age 61.4 +/- 10.2 yr) with early esophageal carcinoma (n = 29) and carcinoma in situ (Cis) (n = 10) fulfilled the criteria for local endoscopic therapy and were treated using endoscopic resection. Ten patients had Cis (group A), 19 had mucosal cancer (group B), and 10 had submucosal cancer (group C). All patients in group C were inoperable or had refused surgery.

RESULTS

A total of 94 resections were performed. Nine of the 10 patients in group A (90%), 19 of the 19 in group B (100%), and 8 of the 10 in group C (80%) achieved a complete response during a mean follow-up period of 29.7 +/- 14.3 months. Tumor-related deaths occurred in three patients (one in group B, who was inoperable; two in group C, who refused surgery). No major complications such as perforation or bleeding requiring blood transfusion occurred. Minor complications were seen in six patients (15%)-three with minor bleeding after endoscopic resection and three with esophageal stenoses, who were successfully treated using injection therapy or dilatation. Calculated 5-yr survival was 90% in group A, 89% in group B, and 0% in group C.

CONCLUSIONS

Endoscopic resection appears to be an effective and safe method of curative treatment in patients with Cis and mucosal squamous-cell carcinomas of the esophagus. The preferred method in patients with submucosal cancer should be esophagectomy or chemoradiotherapy, whenever possible.

Ablative procedures for prevention and treatment of esophageal adenocarcinoma

Ablation of Barrett's mucosa by endoscopic resection, photodynamic therapy or thermoablative methods in combination with adequate acid suppression leads to mucosal replacement largely by squamous epithelium. In appropriately selected cases, these methods have the potential to cure superficial Barrett's neoplasia. Endoscopic resection is an alternative to surgical resection of high-grade intraepithelial neoplasia or early esophageal adenocarcinoma, if the tumor is less than 20 mm in size, is not ulcerated, and does not exhibit differentiation grade 3 or lymph vessel infiltration on histological examination. In the presence of submucosal infiltration, the likelihood of lymph node infiltration is related to the infiltration depth. The risk of a noncurative endoscopic ablative approach has to be weighted against the general risk of surgery. With photodynamic or thermoablative treatment, the completeness of destruction of neoplastic tissue can only be judged at follow-up. These methods are therefore restricted to cases that have an increased surgical risk. Ablation of non-neoplastic Barrett's mucosa is currently not indicated.

Monitoring in situ dosimetry and protoporphyrin IX fluorescence photobleaching in the normal rat esophagus during 5-aminolevulinic acid photodynamic therapy

Experimental therapies for Barrett's esophagus, such as 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), aim to ablate the premalignant Barrett's epithelium. However, the reproducibility of the effects should be improved to optimize treatment. Accurate irradiation with light of a proper wavelength (633 nm), fluence and fluence rate has shown to be critical for successful ALA-PDT. Here, we have used in situ light dosimetry to adjust the fluence rate measured within the esophagus for individual animals and monitored protoporphyrin IX (PpIX) fluorescence photobleaching simultaneously. Rats were administered 200 mg kg-1 ALA (n = 14) or served as control (n = 7). Animals were irradiated with an in situ measured fluence rate of 75 mW cm-2 and a fluence of 54 J cm-2. However, this more accurate method of light dosimetry did not decrease the variation in tissue response. Large differences were also observed in the dynamics of PpIX fluorescence photobleaching in animals that received the same measured illumination parameters. We found that higher PpIX fluorescence photobleaching rates corresponded with more epithelial damage, whereas lower rates corresponded with no response. A two-phased decay in PpIX fluorescence could be identified in the response group, with a rapid initial phase followed by a slower rate of photobleaching. Non-responders did not show the rapid initial decay and had a significantly lower rate of photobleaching during the second phase of the decay (P = 0.012).

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.

Argon plasma coagulation in Barrett's esophagus

Despite the availability of many clinical trials, there is no evidence that APC has any role in the management of Barrett's esophagus. Ablation therapy is not indicated for nondysplastic Barrett's esophagus (and this is true, whatever the technique used), and it should not be performed outside of a carefully designed and approved clinical trial. Indeed, these patients have a low risk of cancer, and there is no evidence that Barrett's esophagus ablation will be of any benefit for these patients. In some cases, APC could be of some help, especially for treating short segments of dysplastic Barrett's esophagus. In this field, however, it competes with the growing indication of mucosectomy, which clearly offers advantages in terms of treatment's quality control assessment.

In situ light dosimetry during photodynamic therapy of Barrett's esophagus with 5-aminolevulinic acid

BACKGROUND AND OBJECTIVES

Previous studies with PhotoDynamic Therapy (PDT) in bladder and bronchi have shown that due to scattering and reflection, the actually delivered fluence rate on the surface in a hollow organ can be significantly higher than expected. In this pilot study, we investigated the differences between the primary calculated and the actual measured fluence rate during PDT of Barrett's Esophagus (BE) using 23 independent clinical measurements in 15 patients.

STUDY DESIGN/MATERIALS AND METHODS

A KTP-dye module laser at 630 nm was used as light source. Light delivery was performed using a cylindrical light diffuser inserted in the center of an inflatable transparent balloon with a length corresponding to the length of the Barrett's epithelium. The total light output power of the cylindrical diffuser was calibrated using an integrating sphere to deliver a primary fluence rate of 100 mW cm(-2). Two fiber-optic pseudo sphere isotropic detectors were placed on the balloon and were used to measure fluence rate at the surface of the esophageal wall during PDT.

RESULTS AND CONCLUSIONS

The actual fluence rate measured was 1.5-3.9 times higher than the primary fluence rate for 630 nm. In general, the fluence rate amplification factor decreased with increasing redness of the tissue and was less for shorter diffusers. Fluence rate variations in time were observed which coincided with patients coughing, movement, and esophageal spasms. These factors combined with inter patient variability of the fluence rate measured appears to justify the routine application of this technique in PDT of BE.

Limited resection for early esophageal cancer?

BACKGROUND

Early squamous cell carcinoma (SCC) and early adenocarcinoma (AC) of the esophagus are potentially curable diseases. The crucial point in treatment is that the depth of tumor infiltration into the mucosal and submucosal layers is correlated with the rate of nodal metastases and therefore with long-term prognosis.

METHODS AND FOCUS

In submucosal SCC with a high rate of nodal metastases curative resection can be achieved only by radical esophagectomy with systematic lymphadenectomy, which remains the treatment of choice for this tumor entity. In submucosal AC the Merendino procedure may offer an alternative since lymphatic invasion occurs at a later stage than in SCC, and locoregional lymph nodes can be adequately resected. Major advantages of this operation over radical esophagectomy include the complete resection of the entire Barrett segment and the lower postoperative morbidity and mortality. Vagal-sparing esophagectomy still lacks adequate oncological evaluation for it to be recommended except in stage I a tumors. For mucosal SCC and AC endoscopic mucosal resection is the treatment of choice but requires intensive follow-up since the rate of complete resections is lower than in limited and radical surgical procedures. On the other hand, a low postoperative morbidity and the functional integrity of the tubular esophagus support the use of endoscopic mucosal resection for mucosal cancer.

Monitoring In Situ Dosimetry and Protoporphyrin IX Fluorescence Photobleaching in the Normal Rat Esophagus During 5-Aminolevulinic Acid Photodynamic Therapy¶

Experimental therapies for Barrett's esophagus, such as 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), aim to ablate the premalignant Barrett's epithelium. However, the reproducibility of the effects should be improved to optimize treatment. Accurate irradiation with light of a proper wavelength (633 nm), fluence and fluence rate has shown to be critical for successful ALA-PDT. Here, we have used in situ light dosimetry to adjust the fluence rate measured within the esophagus for individual animals and monitored protoporphyrin IX (PpIX) fluorescence photobleaching simultaneously. Rats were administered 200 mg kg-1 ALA (n = 14) or served as control (n = 7). Animals were irradiated with an in situ measured fluence rate of 75 mW cm-2 and a fluence of 54 J cm-2. However, this more accurate method of light dosimetry did not decrease the variation in tissue response. Large differences were also observed in the dynamics of PpIX fluorescence photobleaching in animals that received the same measured illumination parameters. We found that higher PpIX fluorescence photobleaching rates corresponded with more epithelial damage, whereas lower rates corresponded with no response. A two-phased decay in PpIX fluorescence could be identified in the response group, with a rapid initial phase followed by a slower rate of photobleaching. Non-responders did not show the rapid initial decay and had a significantly lower rate of photobleaching during the second phase of the decay (P = 0.012).

Photodynamic therapy for dysplastic Barrett esophagus and early esophageal adenocarcinoma

OBJECTIVE

To evaluate our results using photodynamic therapy (PDT) for the treatment of dysplasia or superficial cancer (T1 N0 M0) in patients with Barrett esophagus.

PATIENTS AND METHODS

We retrospectively reviewed our clinical experience with 48 patients (34 patients with high-grade dysplasia and 14 patients with superficial cancer in Barrett esophagus) who had been referred for PDT. Initial evaluation included computed tomography and standard and high-frequency catheter endosonography. Follow-up endoscopy was performed 4 to 6 weeks after PDT with ablation of any residual glandular mucosa, using the argon plasma coagulator. Patients were then followed up indefinitely every 3 to 6 months with computed tomography, endosonography, and endoscopic surveillance.

RESULTS

The median series follow-up was 18.5 months (range, 1-56 months). Apparent complete photoablation of Barrett mucosa and/or superficial neoplasm was documented in 47 of 48 cases. Complications included symptomatic strictures (11 patients), photosensitivity (7 patients), atrial fibrillation (1 patient) or recurrent congestive heart failure (1 patient), and self-limited esophageal perforation (1 patient). Failure to ablate T1 N0 M0 adenocarcinoma occurred in 1 patient.

CONCLUSIONS

Porfimer sodium PDT appears to eradicate dysplastic Barrett mucosa and neoplasia. These results are promising; however, long-term studies are needed to document the efficacy of PDT in reducing the morbidity and mortality in such patients.

Local endoscopic therapy for intraepithelial high-grade neoplasia and early adenocarcinoma in Barrett's oesophagus: acute-phase and intermediate results of a new treatment approach

BACKGROUND

Radical oesophageal resection has until now been regarded as the gold standard for treatment in intraepithelial high-grade neoplasia or early adenocarcinoma of the oesophagus. However, the mortality and morbidity rates are substantial.

DESIGN

A new therapeutic approach involving low-risk endoscopic therapy modalities was examined in the framework of a prospective study.

PATIENTS

A total of 115 patients with intraepithelial high-grade neoplasia (19) and early adenocarcinoma (96) in Barrett's oesophagus.

METHODS

Endoscopic mucosal resection (EMR) was used in 70 patients, and photodynamic therapy (PDT) was used in 32 patients. The two procedures were combined in ten patients. Three patients underwent primary treatment with argon plasma coagulation (APC). The average follow-up was 34 +/- 10 months (range 24-60 months).

RESULTS

Complete local remission was achieved in 98%. The overall complication rate was 9.5%. Major complications, such as perforation and severe bleeding, did not occur. Minor complications included not haemoglobin relevant bleeding (drop of haemoglobin less than 2 g/dl) (5) and stenosis (3) after EMR, and long-lasting odynophagia (1) and sunburn (2) after PDT. In all, 13 patients have died so far, but in only one case due to the underlying disease. The calculated overall 3-year survival rate is 88%. During the follow-up period, a 30% rate of metachronous lesions was observed; endoscopic therapy was performed successfully in all but one of these patients.

CONCLUSIONS

These good acute-phase and intermediate results, along with low morbidity rates and no mortality, suggest that the organ-preserving local endoscopic procedure including EMR and PDT is an attractive alternative to oesophageal resection. Therefore, endoscopic therapy might replace radical oesophageal resection in future in cases of intraepithelial high-grade neoplasia and early mucosal adenocarcinoma in Barrett's oesophagus.

Photodynamic therapy of human Barrett's cancer using 5-aminolaevulinic acid-induced protoporphyrin IX: an in-vivo dosimetry study in athymic nude mice

OBJECTIVE

There has been a dramatic increase in recent years in the incidence of Barrett's oesophagus and the oesophageal adenocarcinoma associated with it. Alongside surgical treatment for early Barrett's carcinomas, endoscopic treatment procedures such as photodynamic therapy (PDT), which have much lower complication and mortality rates, will play an increasing role in the future. In this study, the effects of light energy dose, light fractionation and oxygenation on the efficacy of PDT were investigated for the first time in an in-vivo nude mice tumour model bearing a human Barrett's carcinoma.

DESIGN

A total of 387 NMRI strain (nu/nu) nude mice with thymic aplasia (total 53 controls) were transplanted with human Barrett's carcinoma and treated with laser light at 635 nm (light dose 0-200 J/cm2, fluence rate 400 mW/cm2). 5-Aminolaevulinic acid-induced protoporphyrin IX (5-ALA-PpIX) (100 mg 5-ALA/kg body weight administered orally) was used as the photosensitizer.

METHODS

Fractionation studies were performed at 0, 50, 100 and 150 J/cm2. The light dose was administered in four equal fractions divided by three irradiation-free intervals of 120 s. Oxygenation studies were carried out at 150 J/cm2 with simultaneous oxygen supply of 2, 6 and 8 l oxygen/min.

RESULTS

Dosimetry studies demonstrated a positive correlation between increase in light dose and tumour destruction up to 150 J/cm2 when using either continuous or fractionated light delivery. The optimal light energy dose was 150 J/cm2. Neither fractionation of light nor simultaneous oxygenation enhanced the efficacy of the PDT.

CONCLUSION

This is the first study in the literature that proves the efficiency of PDT with 5-ALA-PpIX in human Barrett's adenocarcinoma and that demonstrates an exact dosimetry of the optimal light energy dose (150 J/cm2). No general recommendation can be made for the use of fractionation or oxygenation in clinical PDT.

Photodynamic therapy using Verteporfin (benzoporphyrin derivative monoacid ring A, BPD-MA) and 630 nm laser light in canine esophagus

BACKGROUND AND OBJECTIVE

Verteporfin is a new photosensitizer with short-term skin photosensitivity. The objective of this preclinical study was to find the light dose that effectively ablates canine esophageal mucosa when delivered 30 minutes after Verteporfin injection.

STUDY DESIGN/MATERIALS AND METHODS

Verteporfin was administered intravenously (0.75 mg/kg). 630 nm light from KTP/Dye laser was delivered using an esophageal Photodynamic therapy (PDT) balloon. In Phase I study, animals were treated 30 minutes after drug injection using 40, 60, and 80 J/cm to find the desired light dose. Using results from phase I and application of reciprocity principle (light dose vs. plasma concentration of drug), additional light doses were calculated for delivery at other times. In phase II, animals were treated at 15, 60, and 120 minutes, using the calculated light doses of 60, 145, and 200 J/cm, respectively. Animals were followed for 2 days to 4 weeks.

RESULTS

In Phase I, 80 J/cm at 30 minutes induced total mucosal ablation. In Phase II, light doses of 60, 145, and 200 J/cm induced similar mucosal injuries when delivered at 15, 60, and 120 minutes, respectively.

CONCLUSIONS

Effective mucosal ablation in canine esophagus was achieved using Verteporfin and 630 nm light doses of 60, 80, 145, and 200 J/cm when delivered at 15, 30, 60, and 120 minutes after the drug injection, respectively.

Barrett oesophagus and adenocarcinoma: an overview of epidemiologic, conceptual and clinical issues

A steady increase in the incidence of adenocarcinoma of the oesophagus and oesophagogastric junction has been observed in Western countries. Patients with distinctive-type Barrett oesophagus are predisposed to developing adenocarcinoma of the oesophagus. Distinctive-type Barrett oesophagus is defined by the presence of intestinal-like goblet cells anywhere in the oesophagus. Adenocarcinomas of the oesophagogastric junction may be associated with short segments of intestinal-type columnar epithelium in the distal oesophagus. Prognosis after surgical resection for cancer of the oesophagus or oesophagogastric junction is strongly affected by the extent of the disease at the time of diagnosis. The identification of Barrett oesophagus as a premalignant condition, the recognition of a stepwise neoplastic progression, along with the poor survival rates of advanced oesophageal adenocarcinoma have initiated the practice of endoscopic biopsy surveillance for patients with Barrett oesophagus. There is supporting evidence that endoscopic biopsy surveillance of Barrett oesophagus permits detection of malignancy at an early stage with favourable results after oesophageal resection. Endoscopic treatment modalities should at this time not be generally adopted in the management of patients with early invasive adenocarcinoma of the oesophagus or oesophagogastric junction.

5-Aminolevulinic acid-based photochemical internalization of the immunotoxin MOC31-gelonin generates synergistic cytotoxic effects in vitro

Photochemical internalization (PCI) is a novel method for the endosomal or lysosomal release of membrane-impermeable molecules into the cytosol of target cells. This novel technology is based on the photodynamically induced rupture of endocytic vesicles preloaded with molecules of therapeutic interest. PCI of the ribosome-inactivating plant toxin gelonin and the immunotoxin monoclonal antibody 31 (MOC31) gelonin has been performed previously by the use of the endocytic vesicle-localizing photosensitizers TPPS2a and AIPcS2a and light, demonstrating synergistic toxicity against the more than 20 different cell lines tested, most of them of neoplastic origin. In this study we demonstrate that 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) is also capable of inducing PCI of MOC31-gelonin in the human colon adenocarcinoma cell line WiDr. The cells were incubated with 1 mM 5-ALA for up to 8 h in serum-free medium and from 24 to 96 h in serum-containing medium. Fluorescence microscopical studies indicate a partial plasma membrane localization of PpIX when 5-ALA was applied under serum-free conditions. This plasma membrane localization was not seen when 5-ALA was given in the presence of serum. There was a granular component of the PpIX localization in addition to a diffuse cytoplasmic localization. The granular component resembled the localization of the fluorescent dye conjugate Alexa-gelonin and the lysosomal localizing dye acridine orange. Our present results provide evidence for an endocytic vesicle-associated fraction of PpIX after 5-ALA incubation of the WiDr cells. We demonstrate that PCI, by combining 5-ALA, MOC31-gelonin and light, induces a synergistic cytotoxic effect against the WiDr cells.

5-Aminolaevulinic acid-mediated photodynamic therapy in multidrug resistant leukemia cells

To verify if photodynamic therapy (PDT) could overcome multidrug resistance (MDR) when it it applied to eradicate minimal residual disease in patients with leukemia, we investigated the fluorescence kinetics of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) and the effect of subsequent photodynamic therapy on MDR leukemia cells, which express P-glycoprotein (P-gp), as well as on their parent cells. Evaluation of PpIX accumulation by flow cytometry showed that PpIX accumulated at higher levels in mdr-1 gene-transduced MDR cells (NB4/MDR) and at lower levels in doxorubicin-induced MDR cells (NOMO-1/ADR) than in their parent cells. A P-gp inhibitor could not increase PpIX accumulation. Measurement of extracellular PpIX concentration by fluorescence spectrometry showed that P-gp did not mediate the fluorescence kinetics of ALA-induced PpIX production. Assessment of ferrochelatase activity using high-performance liquid chromatography indicated that PpIX accumulation in drug-induced MDR cells was probably regulated by this enzyme. Assessment of phototoxicity of PDT using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that PDT was effective in NB4, NB4/MDR, NOMO-1 and NOMO-1/ADR cells, which accumulated high levels of PpIX, but not effective in K562 and K562/ADR cell lines, which accumulated relatively low levels of PpIX. These findings demonstrate that P-gp does not mediate the ALA-fluorescence kinetics, and multidrug resistant leukemia cells do not have cross-resistance to ALA-PDT.

Aminolevulinic acid: pharmacological profile and clinical indication

The role of aminolevulinic acid hydrochloride (ALA) in photodynamic therapy (PDT) of in situ neoplasias and tumours of epithelial tumours is steadily increasing and it has been shown to be the drug with most clinical use in PDT. In dermatology, topical PDT with ALA is already postulated to be the treatment of choice for actinic keratoses and superficial basal cell carcinomas. In gastroenterology, pulmonology, uro- and nephrology, neurology and gynaecology ALA has an important role as a photosensitiser not only in the diagnosis of neoplastic tissue but as therapy; first experiences have been made with PDT in these organs. Besides the therapeutic efficacy of this technique, the fluorescence of ALA-induced porphyrins can be effectively used to detect and delineate epithelial and endothelial neoplasms. In dermatology, other indications for ALA-treatment are non-tumoural applications, especially psoriasis, viral-induced diseases, or acne vulgaris. ALA is an effective compound in the diagnosis or therapy of various epithelial and endothelial neoplastic lesions.

Migraine and beyond: cardiovascular therapeutic potential for CGRP modulators

CGRP is a potent vasodilator that has been shown to have a physiological and/or pathological role in neurogenic inflammation, headaches including migraine, thermal injury, circulatory shock, pregnancy and menopause, hypertension and heart failure and is known to be cardioprotective. CGRP is also a positive inotrope and increases heart rate. Clinical trials have shown beneficial effects of the vasodilatory action of CGRP in hypertension, angina, heart failure, Raynaud's disease and venous stasis ulcers. However, the clinical potential of CGRP is limited as it has to be given by infusion and is quickly broken down. Oral long acting CGRP-mimetics may have potential in disorders in which CGRP has been shown to be beneficial. CGRP-mimetics include capsaicin/vanilloid receptor agonists and gene transfer of an adenoviral vector that encodes prepro-CGRP. CGRP inhibitors have therapeutic potential in conditions in which excessive CGRP-mediated vasodilatation is present; neurogenic inflammation, migraine and other headaches, thermal injury, circulatory shock and flushing in menopause. CGRP inhibitors include capsaicin, antagonists at capsaicin/vanilloid receptors, civamide, CGRP receptor antagonists and 5-HT1D-receptor agonists. Drugs that are 5-HT1D-receptor agonists, the 'triptans' are already commonly used in migraine and the first small molecule CGRP antagonist, BIBN4096BS, is under clinical investigation for the treatment of migraine.

Mucosal ablation therapy of barrett esophagus

Barrett esophagus is defined by the metaplasia of existing squamous mucosa into a specialized intestinal-type mucosa. The importance of this metaplasia is the association of this condition with the development of adenocarcinoma of the esophagus. Elimination of the metaplastic mucosa may decrease the cancer risk. Currently, several forms of therapy have evolved with the goal of replacing the specialized mucosa with normal squamous mucosa. These proposed treatments include photodynamic therapy and thermal techniques. The effectiveness of photodynamic therapy varies depending on the pharmaceutical photosensitizer used and the wavelength of light applied to activate the drug. Thermal techniques include multipolar coagulation, argon plasma coagulation, KTP:YAG laser therapy, Nd:YAG laser therapy, and argon laser therapy. Finally, mucosal resection has been attempted through the endoscope to remove large areas of the Barrett mucosa. All of these ablative strategies attempt to destroy the metaplastic mucosa and promote the regrowth of squamous epithelium. These therapies have demonstrated the ability to "reverse" the metaplasia to varying degrees, but a decrease in cancer risk has not been demonstrated conclusively with any of these treatment methods.