Photodynamic therapy of superficial esophageal cancer with a transparent hood

Targeted Photodynamic Diagnosis and Therapy for Esophageal Cancer: Potential Role of Functionalized Nanomedicine

Esophageal cancer is often diagnosed at the late stage when cancer has already spread and is characterized by a poor prognosis. Therefore, early diagnosis is vital for a better and efficient treatment outcome. Upper endoscopy with biopsy is the standard diagnostic tool for esophageal cancer but is challenging to diagnose at its premalignant stage, while conventional treatments such as surgery, chemotherapy, and irradiation therapy, are challenging to eliminate the tumor. Photodynamic diagnosis (PDD) and therapy (PDT) modalities that employ photosensitizers (PSs) are emerging diagnostic and therapeutic strategies for esophageal cancer. However, some flaws associated with the classic PSs have limited their clinical applications. Functionalized nanomedicine has emerged as a potential drug delivery system to enhance PS drug biodistribution and cellular internalization. The conjugation of PSs with functionalized nanomedicine enables increased localization within esophageal cancer cells due to improved solubility and stability in blood circulation. This review highlights PS drugs used for PDD and PDT for esophageal cancer. In addition, it focuses on the various functionalized nanomedicine explored for esophageal cancer and their role in targeted PDD and PDT for diagnosis and treatment.

Photodynamic Therapy for Esophageal Cancer

Photodynamic therapy, a curative local treatment for esophageal squamous cell carcinoma, involves a photosensitizing drug (photosensitizer) with affinity for tumors and a photodynamic reaction triggered by laser light. Previously, photodynamic therapy was used to treat superficial esophageal squamous cell carcinoma judged to be difficult to undergo endoscopic resection. Recently, photodynamic therapy has mainly been performed for local failure after chemoradiotherapy. Although surgery is the most promising treatment for local failure after chemoradiotherapy, its morbidity and mortality rates are high. Endoscopic resection is feasible for local failure after chemoradiotherapy but requires advanced skills, and its indication is limited to within the submucosal layer by depth. Photodynamic therapy is less invasive than surgery and has a wider indication than endoscopic resection. Porfimer sodium (a first-generation photosensitizer) causes a high frequency of side effects related to photosensitivity and requires the long-term sunshade period. Talaporfin (a second-generation photosensitizer) requires a much shorter sun-shade period than porfimer sodium. Photodynamic therapy will profoundly change treatment strategies for local failure after chemoradiotherapy.

Role of photodynamic therapy in the treatment of esophageal cancer

Photodynamic therapy (PDT), a treatment of choice for cancer, induces a photochemical reaction, thereby eradicating tumor cells. This is achieved through the administration of a photosensitizer drug, which is activated with a laser after localization to the tumor mass, and is an approved curative endoscopic ablative treatment for superficial esophageal squamous cell carcinoma (ESCC) in Japan. PDT has been approved for dysplastic Barrett's esophagus and as a palliative treatment for patients with symptomatic obstructive esophageal cancer in US. However, its adverse events and complicated procedure and the development of alternative endoscopic procedures such as endoscopic submucosal dissection, radiofrequency ablation and cryotherapy, have largely limited the practice of PDT in esophageal cancer worldwide. Recently, owing to the invention of second-generation PDT using talaporfin sodium and diode laser, PDT can be performed with less phototoxicity and therefore has regained popularity in the treatment of ESCC. As a salvage treatment for patients with local failure after chemoradiotherapy (CRT), PDT has shown promising complete response with less phototoxicity and shorter sun shade period. In addition, the efficacy and safety of PDT in patients with local failure of ESCC after CRT were shown in several clinical trials. The direction of the study interest of the next-generation PDT is the safety and potential expansion of the indications for its application in the future. This review covers the PDT for the treatment of ESCC and dysplastic Barrett's esophagus, with special focus on the role of PDT in practice for esophageal cancer.

Application of photodynamic therapy in gastrointestinal disorders: an outdated or re-emerging technique?

Photodynamic therapy (PDT) is a promising therapeutic modality that involves the administration of a photosensitizer followed by local illumination with a specific wavelength of light in the presence of oxygen. PDT is minimally invasive, has high selectivity for cancer, and has good patient compliance due to the simplicity of the procedure; therefore, PDT is widely used as a palliative and salvage treatment in patients with various gastrointestinal malignancies. When used as a salvage treatment for locoregional failures after definitive chemoradiotherapy for esophageal cancer, favorable results have been reported. PDT in conjunction with biliary stenting is a promising palliative treatment for unresectable cholangiocarcinoma, and can be used as an advanced diagnostic and therapeutic strategy in peritoneal dissemination of gastric cancer. Recent clinical reports of PDT for treating non-resectable pancreatic cancer also show promising results. To widen the application of PDT, the integration of PDT with molecular imaging and nanotechnology is being extensively studied. Based on these new developments, PDT is likely to re-emerge as a valuable technique in the treatment of diverse gastrointestinal diseases.

Photodynamic therapy for esophageal cancer

Photodynamic therapy (PDT) is a treatment that uses a photosensitizing drug that is administered to the patient, localized to a tumor, and then activated with a laser to induce a photochemical reaction to destroy the cell. PDT using porfimer sodium followed by excimer dye laser irradiation is approved as a curative treatment for superficial esophageal cancer in Japan. While endoscopic submucosal dissection (ESD) is currently more popular for esophageal cancer, there is evidence to support PDT as an alternative treatment and as a salvage treatment for local failure after chemoradiotherapy (CRT). A photosensitizing agent has also been developed that requires a shorter sun shade period after administration, and studies are currently underway to establish an esophageal cancer indication for this next-generation PDT in Japan.

Photodynamic therapy as salvage treatment for local failure after chemoradiotherapy in patients with esophageal squamous cell carcinoma: a phase II study

Local failure at the primary site is a major problem after chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC). Salvage surgery is the only treatment option with curative intent, but it is associated with high morbidity and mortality. The aim of this study was to evaluate the efficacy and safety of salvage photodynamic therapy (PDT) after CRT. Patients with histologically proven local failure limited to the submucosal layer, and without any metastasis after definitive CRT (≥50 Gy) for ESCC were enrolled in the study. PDT began with intravenous administration of 2 mg/kg of porfimer sodium followed 48-72 hr later by excimer dye laser irradiation with a fluence of 75 J/cm2. The primary endpoint was a complete response (CR) to treatment with PDT, and the secondary endpoints were toxicity related to PDT, progression-free survival (PFS) and overall survival (OS). Twenty-five patients were enrolled in the study. A CR was attained in 19 of 25 patients treated with PDT (CR rate, 76%; 95% CI, 55-91%). One treatment-related death (4%) caused by gastrointestinal hemorrhage at the irradiated site occurred 33 days after PDT. No adverse events greater than grade 3 were related to PDT in the other patients. After a median follow-up of 48 months after PDT, the PFS and OS at 3 years were 40% (95% CI, 21-59%) and 38% (95% CI, 17-60%), respectively. PDT is a potentially curative and tolerable salvage treatment after CRT for carefully selected patients with local failure without any metastasis.

Photodynamic therapy for large superficial squamous cell carcinoma of the esophagus

BACKGROUND

Photodynamic therapy (PDT) has been found to be safe and effective in patients with small early esophageal squamous cell carcinoma (SCC). However, its efficacy for widespread superficial SCC has not yet been confirmed.

OBJECTIVE

To assess the long-term survival, complications, and recurrence of PDT for large superficial esophageal SCC.

DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

A total of 38 patients with superficial SCC of the esophagus. All patients had a large unifocal lesion or multifocal lesions that were too large to be resected endoscopically. In addition, all patients were physiologically unfit for esophagectomy or had refused surgery.

INTERVENTIONS

PDT with porfimer sodium.

MAIN OUTCOME MEASUREMENTS

Clinical follow-up, long-term survival, complications, and recurrence were evaluated.

RESULTS

Thirty-one patients (82%) had mucosal cancer (T1m), and 7 (18%) had submucosal cancer (T1sm). No patient had lymph node involvement. Nineteen patients had other primary malignancies. Complete remission was achieved in 33 (87%). At the time of writing, 28 patients (74%) were alive without recurrence. After a median follow-up period of 64 months (range, 7-125 months) after PDT, the overall 5-year survival rate was 76%. There was no treatment-related mortality.

LIMITATIONS

Retrospective study with a small number of patients.

CONCLUSIONS

This long-term follow-up study revealed that PDT was a potentially curative treatment for large superficial esophageal SCC. PDT might be a reasonable alternative to esophagectomy or to endoscopic resection for patients with superficial SCC of the esophagus without lymph node metastasis.

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.

Laser Ablation Therapies for Barrett’s Esophagus

The metaplastic change of the normal squamous epithelium of the distal esophagus into a specialized columnar epithelium is known as Barrett's esophagus (BE) and is associated with an increased risk of adenocarcinoma of the esophagus. It is a frequent complication of gastroesophageal reflux disease (GERD) and up to 10% of patients with GERD suffer from BE. The progression to dysplasia increases the risk of cancer development and the annual risk of developing cancer in Barrett's esophagus is estimated to be 0.5% per year. The management of BE with high grade dysplasia (HGD) is controversial. Recent innovations in endoscopic therapy have allowed for the development of multiple endoscopic techniques, such as photodynamic therapy (PDT), argon plasma coagulation (APC), and endoscopic mucosal resection. In this article, we will discuss primarily photodynamic therapy, and other ablative technologies such as argon plasma coagulation in the treatment of BE.

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).