Salvage photodynamic therapy for local failure after chemoradiotherapy for esophageal squamous cell carcinoma

Importance of early detection of esophageal cancer before the tumor progresses too much for effective treatment

This editorial comments on an article by Qu et al published in the World Journal of Gastrointestinal Oncology. It focuses on the importance of early detection of esophageal cancer, including recurrence or secondary malignancy after chemoradiotherapy (CRT). Endoscopic resection is the first choice for treatment for esophageal cancer remaining within the mucous membrane, while surgery or radical CRT are treatment options for advanced stages depending on the patient's general condition and desire. Although these treatments are potentially curative, they are more invasive than endoscopic resection. Early-stage esophageal cancer is often asymptomatic and difficult to detect. Uniform periodic endoscopy is unrealistic. Although less burdensome tests exist, including liquid biopsy and urinary biomarkers, these have not yet been widely used in clinical practice. Early detection is important after radical CRT because the local recurrence rate is higher than that after surgery. However, endoscopic resection or photodynamic therapy is indicated if detected in the early stages, and positive results have been reported. Early detection of esophageal cancer is crucial. Endoscopy is the main diagnostic method; however, new and less burdensome methods should be established to ensure early treatment for patients with esophageal cancer.

Transvascular delivery of talaporfin sodium to subcutaneous tumors in mice by nanosecond pulsed laser-induced photomechanical waves

BACKGROUND

We previously developed a site-specific transvascular drug delivery system (DDS) based on photomechanical waves (PMWs) or laser-induced stress/shock waves (LISWs). In this study, we investigated the validity of this method to deliver a clinical photosensitizer, talaporfin sodium (TS), to subcutaneous tumors in mice and to enhance the efficacy of photodynamic therapy (PDT).

METHODS

TS solution (2.5 mg/kg) was intravenously injected into mice. Immediately thereafter, PMWs were applied to the tumor by irradiating a laser target with a Q-switched ruby laser pulse (0.8 J/cm2). Five hours after TS administration, some tumors were excised to evaluate the depth distribution of the delivered TS under a fluorescence microscope. Other tumors were subjected to PDT by irradiating the tissues with a 665 nm continuous-wave laser diode (75 mW/cm2, 667 s) at this timepoint. The effects of PDT were evaluated on the basis of the two primary therapeutic mechanisms of TS-mediated PDT: i) damage to tumor cells and ii) damage to endothelial cells of tumor vessels, i.e., the vascular shutdown effect on tumors.

RESULTS

PMW application significantly increased the accumulation of TS in the tumor parenchyma but not in the tumor vessel walls; the endothelial cell junctions of tumor vessels should be the route of TS delivery enhanced by PMWs. Thus, as a result of PMW application followed by PDT, while the vascular shutdown effect on the tumors was not enhanced, direct damage to the tumor cells was increased, resulting in significant tumor growth retardation without body weight loss for 7 days after treatment.

The use of nanomaterials in advancing photodynamic therapy (PDT) for deep-seated tumors and synergy with radiotherapy

Photodynamic therapy (PDT) has been under development for at least 40 years. Multiple studies have demonstrated significant anti-tumor efficacy with limited toxicity concerns. PDT was expected to become a major new therapeutic option in treating localized cancer. However, despite a shifting focus in oncology to aggressive local therapies, PDT has not to date gained widespread acceptance as a standard-of-care option. A major factor is the technical challenge of treating deep-seated and large tumors, due to the limited penetration and variability of the activating light in tissue. Poor tumor selectivity of PDT sensitizers has been problematic for many applications. Attempts to mitigate these limitations with the use of multiple interstitial fiberoptic catheters to deliver the light, new generations of photosensitizer with longer-wavelength activation, oxygen independence and better tumor specificity, as well as improved dosimetry and treatment planning are starting to show encouraging results. Nanomaterials used either as photosensitizers per se or to improve delivery of molecular photosensitizers is an emerging area of research. PDT can also benefit radiotherapy patients due to its complementary and potentially synergistic mechanisms-of-action, ability to treat radioresistant tumors and upregulation of anti-tumoral immune effects. Furthermore, recent advances may allow ionizing radiation energy, including high-energy X-rays, to replace external light sources, opening a novel therapeutic strategy (radioPDT), which is facilitated by novel nanomaterials. This may provide the best of both worlds by combining the precise targeting and treatment depth/volume capabilities of radiation therapy with the high therapeutic index and biological advantages of PDT, without increasing toxicities. Achieving this, however, will require novel agents, primarily developed with nanomaterials. This is under active investigation by many research groups using different approaches.

Definitive concurrent chemoradiotherapy with docetaxel plus cisplatin versus 5-fluorouracil plus cisplatin in patients with esophageal squamous cell carcinoma: long-term follow-up results of a phase II randomized controlled trial

BACKGROUND

Definitive radiotherapy plus concurrent chemotherapy has been a standard treatment for esophagus patients who are unfit to undergo surgery. However, there are a variety of concurrent chemotherapy regimens with varying efficacy. In this phase II prospective study, we compared the efficacy and toxicity of DP (docetaxel and cisplatin) and PF (cisplatin and 5-fluorouracil) regimens with concurrent chemoradiotherapy (CCRT) in patients with esophageal squamous cell carcinoma (ESCC) and analyzed the 5-year overall survival (OS) and progression free survival (PFS). We also summarized the salvage treatments and late toxicities.

METHODS

We enrolled 86 patients with clinical stage II-IVA from the Sun Yat-sen University Cancer Center. The patients were divided into two groups: PF group (41) and DP group (45). Statistics were analyzed using SPSS version 19.0.

RESULTS

The 5-year OS rates were 62.9% ± 7.6% in PF group, and 52.7% ± 7.5% in DP group (P = 0.131), respectively. The 5-year PFS rates were 43.9% ± 7.8% for PF group, and 40.0% ± 7.3% for DP group (P = 0.398), respectively. Sixteen patients in the DP group and thirteen in the PF group received salvage treatment. For those patients with local residual or local recurrent disease, the median survival time after salvage treatment was 13.5 months and the 1, 2, and 3-year survival rates were 79.0%, 50.3%, and 43.1%, respectively. For all patients, thirteen (15.1%) had Grade 2 late cardiac toxicities. One patient had Grade 2 pleural effusion and required diuretic. Most patients with pneumonia are mild, and only one patient in PF group had Grade 2 pneumonia. One patient in the DP group developed tracheoesophageal fistula.

CONCLUSIONS

The 5-year follow-up confirmed that definitive CCRT with the DP regimen did not improve the treatment response, OS, or PFS in patients with ESCC compared to the PF regimen. The PF regimen remains the standard regimen for definitive CCRT for patients with locally advanced ESCC. Long-term follow-up also suggested that appropriate and active salvage treatment has a survival benefit for some patients, and late cardiopulmonary toxicities should be noticed during follow-up.

TRIAL REGISTRATION

The trial was registered at https://clinicaltrials.gov (ClinicalTrials.gov Identifier: NCT02969473, October 2010).

Novel Photodynamic Therapy for Esophageal Squamous Cell Carcinoma following Radiotherapy

Radiotherapy (RT) or chemoradiotherapy (CRT) are frequently selected as treatments for esophageal squamous cell carcinoma (ESCC). However, salvage treatment remains challenging when endoscopic resection is not indicated for residual or recurrent ESCC following RT or CRT. Recently, owing to the emergence of second-generation photodynamic therapy (PDT) using talaporfin sodium, PDT can be performed with less phototoxicity and therefore has regained popularity in the treatment of ESCC. In this study, the effectiveness and safety of second-generation PDT in patients with residual or recurrent ESCC following RT or CRT were examined. Local complete response (L-CR) rates, procedure-related adverse events, and prognosis were evaluated. In 12 patients with 20 ESCC lesions, the L-CR rates were 95.0%. Perforation, postoperative bleeding, and photosensitivity were not observed. Esophageal stricture following PDT developed in one patient, but this could be addressed using balloon dilation. During a median follow-up period of 12 (range, 3-42) months, the 3-year cause-specific survival rate was 85.7%. Even in patients with a Charlson comorbidity index score ≥ 3, the 2-year overall survival rates were 100%. In conclusion, PDT was an efficacious and a safe salvage treatment in patients with local residual or recurrent ESCC following RT or CRT.

Assessment of photodynamic therapy as a salvage treatment for local failure after chemoradiotherapy or radiotherapy for esophageal cancer in patients aged 80 years or older

Objectives

Chemoradiotherapy (CRT) or radiotherapy (RT) alone is often the treatment of choice for elderly patients with esophageal cancer with the expectation of organ preservation. However, salvage treatment remains a problem when endoscopic resection is not indicated for local failure after CRT/RT. Photodynamic therapy (PDT) is indicated for local failure after CRT/RT, but there are few reports on its efficacy and safety in elderly patients. This study aimed to assess the outcome of PDT for local failure after CRT/RT for esophageal cancer in elderly patients.

Methods

This retrospective single-center study included 42 patients who first underwent PDT between April 2013 and June 2021. Patients aged ≥80 and <80 years were classified into the elderly and nonelderly groups, respectively. Local complete response rate, overall survival, progression-free survival, and incidence of adverse events related to PDT were compared retrospectively between the groups.

Results

The local complete response rate was 93.3% in the elderly group and 85.7 in the non-elderly group. The 2-year overall survival rate was 68.6% and 72.5%, and the 2-year progression-free survival rate was 49.5% and 70.0% in the elderly and nonelderly groups, respectively. There was no significant difference in any of these outcomes between the groups. In terms of adverse events, pneumonia and delirium tended to occur more frequently in the elderly group, but there were no serious adverse events in either group.

Conclusion

The outcome of salvage PDT in the local control was comparable between the elderly and nonelderly patients for local failure after CRT/RT for esophageal cancer.

Usefulness of endoscopic ultrasound in predicting treatment efficacy of salvage endoscopic therapy for local failure after chemoradiotherapy for esophageal squamous cell carcinoma

BACKGROUND

Salvage endoscopic therapy, including endoscopic resection (ER) and photodynamic therapy (PDT), is effective for esophageal squamous cell carcinoma (ESCC) in local failure after chemoradiotherapy (CRT). Resection with pathologically vertical margin-negative (VM0) for ER and local complete response (L-CR) for PDT are important surrogate prognostic markers for each therapy's efficacy. We aimed to evaluate the usefulness of endoscopic ultrasound (EUS) in predicting the efficacy of salvage endoscopic therapy in local failure after CRT for ESCC.

METHODS

We included patients who underwent EUS followed by ER or PDT for local failure after CRT or radiotherapy for ESCC from 2006 to 2020. We evaluated EUS findings associated with VM0 resection for ER and L-CR for PDT, which included the status of the outermost part of the submucosal layer, tumor thickness, and tumor invasion length into the muscularis propria (MP) layer.

RESULTS

Thirty and 47 patients were enrolled into the ER and PDT groups, respectively. The VM0 resection rate in the ER group was 87% (26/30). The EUS findings associated with VM0 resection were tumor thickness < 2.3 mm (p = 0.01) and preserved hyperechoic line of the outermost part of the submucosa layer (p < 0.01). The L-CR rate in the PDT group was 69% (32/47). The EUS findings associated with L-CR were tumor thickness < 5.0 mm (p < 0.01) and tumor invasion length into the MP layer < 1.6 mm (p = 0.03).

CONCLUSIONS

EUS can be useful in predicting the efficacy of salvage endoscopic treatment for local failure after CRT for ESCC.

Recurrent metastasis risk factors in esophageal cancer after salvage endoscopic resection for local failure following chemoradiotherapy

OBJECTIVES

Although salvage endoscopic resection is an optimal treatment for local failure after chemoradiotherapy for esophageal squamous cell carcinoma, recurrent metastasis (lymph node and/or distant metastasis) after salvage endoscopic resection may occur with a certain degree of unavoidable frequency and is associated with a poor prognosis. However, the risk factors for recurrent metastasis are unclear. This study aimed to evaluate the risk factors for recurrent metastasis after salvage endoscopic resection.

METHODS

Patients who underwent salvage endoscopic resection for local failure after chemoradiotherapy/radiotherapy were analyzed in this single-center, retrospective study. We evaluated the cumulative incidence rates of recurrent metastases, overall survival, and the risk factors for recurrent metastasis after salvage endoscopic resection.

RESULTS

We analyzed 132 patients. The 5-year cumulative incidence rate of recurrent metastases after salvage endoscopic resection was 25.7%. The 5-year overall survival rates in all patients and in patients with recurrent metastasis were 66.8% and 22.5%, respectively. Local failure pattern with a residual lesion after chemoradiotherapy/radiotherapy (subdistribution hazard ratio 2.34; P = 0.012) and the presence of lymphatic invasion in salvage endoscopic resection specimen (subdistribution hazard ratio 3.20; P = 0.002) were significant risk factors for recurrent metastasis.

CONCLUSIONS

Patients with local failure pattern with a residual lesion after chemoradiotherapy/radiotherapy and presence of lymphatic invasion have a high risk for recurrent metastasis. Thus, appropriate surveillance for these patients should be considered.

Efficacy and safety of second photodynamic therapy for local failure after salvage photodynamic therapy for esophageal cancer

OBJECTIVES

Photodynamic therapy (PDT) is an optional salvage treatment for local failure of esophageal squamous cell carcinoma (ESCC) after chemoradiotherapy; however, local failure after PDT sometimes occurs. In such cases, second PDT is sometimes attempted, but its outcomes remain unclear. This study aimed to evaluate the efficacy and safety of second PDT.

METHODS

We enrolled patients who underwent PDT for local failure of ESCC after chemoradiotherapy. We retrospectively evaluated local-complete response (L-CR) rate and clinical outcomes of first and second PDT. The indications for PDT were lesions within the muscle layer, <3 cm in size, and <3/4 of the esophageal circumference; not suitable for salvage surgery; and absence of metastasis. Second PDT was avoided when lesions were apparently refractory to first PDT, e.g. persistence of submucosal tumor-like protruded component or rapid regrowth of tumor at the ulceration after first PDT. L-CR was defined as endoscopic disappearance of tumor and post-PDT ulcer and absence of cancer cells histologically.

RESULTS

Among 82 patients who underwent first PDT, 27 underwent second PDT. The L-CR rates with first and second PDT were 63.0% and 40.7%, respectively. The 2-year overall survival rates after second PDT in patients with L-CR and local-nonCR were 79.5% and 40.5%, respectively. Five of 11 patients with L-CR survived without any recurrence. No grade ≥3 adverse events occurred.

CONCLUSIONS

Second PDT demonstrated excellent safety and acceptable efficacy; therefore, it could be a useful treatment for local failure after first PDT.

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.

Salvage treatment after definitive chemoradiotherapy for esophageal squamous cell carcinoma

Definitive chemoradiotherapy (dCRT) for the esophageal squamous cell carcinoma (ESCC) is performed for patients with cT4 disease without distant metastasis and also for those with cStage I-III who are unable to tolerate or who refuse surgery. The rates of clinical complete response (cCR) after dCRT differ depending on the cStage, and patients who once achieved cCR frequently experience tumor recurrence. For those with residual tumor or with recurrence, salvage treatment is performed to achieve a cure. Several procedures have been reported as salvage treatments. Salvage esophagectomy is associated with high rates of morbidity and mortality, but can offer long-term survival. With R0 resection, with cCR to dCRT, pulmonary complications appear to be important prognostic factors affecting overall survival (OS). Lymphadenectomy is performed for the patients with lymph node metastasis without recurrence of primary lesions or distant metastasis, but the contribution to long-term OS is unclear. Metastasectomy is performed when distant metastasis is limited to the lung and there are few lesions, possibly contributing to long-term OS. Endoscopic resection and photodynamic therapy are indicated for cT1a and cT1-2 residual or recurrent tumors, respectively, and can yield favorable outcomes. Re-CRT and re-radiotherapy are performed for the patients with contraindications for surgery, but neither appears to contribute to long-term OS despite high incidences of esophageal fistula and perforation.

Clinical Practice of Photodynamic Therapy Using Talaporfin Sodium for Esophageal Cancer

Photodynamic therapy (PDT) using a conventional photosensitizer was approved for esophageal cancer in the early 1990s; however, it was replaced by other conventional treatment modalities in clinical practice because of the high frequency of cutaneous phototoxicity and esophageal stricture after the procedure. The second-generation photosensitizer, talaporfin sodium, which features more rapid clearance from the body, was developed to reduce skin phototoxicity, and talaporfin sodium can be excited at longer-wavelength lights comparing with a conventional photosensitizer. Endoscopic PDT using talaporfin sodium was initially developed for the curative treatment of central-type early lung cancer in Japan, and was approved in the early 2000s. After preclinical experiments, PDT using talaporfin sodium was investigated for patients with local failure after chemoradiotherapy, which was the most serious unmet need in the practice of esophageal cancer. According to the favorable results of a multi-institutional clinical trial, PDT using talaporfin sodium was approved as an endoscopic salvage treatment for patients with local failure after chemoradiotherapy for esophageal cancer. While PDT using talaporfin sodium is gradually spreading in clinical practice, further evaluation at the point of clinical benefit is necessary to determine the importance of PDT in the treatment of esophageal cancer.

Association of local complete response with prognosis after salvage photodynamic therapy for esophageal squamous cell carcinoma

OBJECTIVES

Photodynamic therapy (PDT) is an effective salvage endoscopic treatment for local failure at the primary site after chemoradiotherapy (CRT) in esophageal cancer patients. However, the contribution of local control by salvage PDT to the prognosis is unclear. We investigated whether complete response at primary site by salvage PDT could improve the prognosis.

METHODS

Between January 2008 and March 2016, 34 patients received salvage PDT for local failure of esophageal cancer limited to stage T1-2 after definitive CRT or radiotherapy. Local complete response (L-CR) rate, adverse events, overall survival (OS), and progression-free survival (PFS) were assessed retrospectively.

RESULTS

Local complete response rates after PDT were 68% (23/34; 95% CI, 50-83%) in all patients: 81% (17/21; 95% CI, 58-95%) for stage T1 and 46% (6/13; 95% CI, 19-75%) for stage T2 patients. Grade 3 esophageal stricture occurred in one patient. The median follow-up was 26.0 months (range, 3.7-93.6 months); 21 patients died. The median survival times were 54.3 months in patients who achieved L-CR after PDT (L-CR group) and 19.8 months in those who did not (non-CR group). The 2-year OS rates were 79% (95% CI, 54-92%) in the L-CR group and 40% (95% CI, 11-68%) in the non-CR group (P = 0.0389; log-rank test). The median PFS was 21.2 months in the L-CR group and 1.9 months in the non-CR group (P < 0.001; log-rank test).

CONCLUSION

Achieving L-CR by salvage PDT for local failure after CRT in esophageal cancer was associated with good prognosis.

Clinical Efficacy of HiPorfin Photodynamic Therapy for Advanced Obstructive Esophageal Cancer

Objective:

To explore the clinical efficacy of HiPorfin photodynamic therapy for advanced esophageal cancer and evaluate its impact on survival.

Methods:

Retrospective analysis of 32 patients with advanced obstructive esophageal cancer at our institution from September 2013 to December 2016. HiPorfin was infused as the photosensitizer at a dose of 5 mg/kg, and after 48 hours, 630-nm laser irradiation was subsequently performed through an optical fiber that passed through the biopsy channel of a flexible endoscope.

Results:

The effectiveness rate was 78.1% (25/32), and the significant efficacy rate was 56.3% (18/32). The dysphagia score decreased from 3.43 ± 0.73 to 1.79 ± 0.53 (P < .05). There was no grade 3 or more toxicity. The median overall survival was estimated to be 16 months. Univariate analysis showed higher overall survival with a Karnofsky Performance Status score ≥80 compared with a Karnofsky Performance Status score <80 (hazard ratio: 2.626; 95% CI: 1.091-6.322; P = .024). Overall survival was higher in patients who had received radiation therapy than in patients who did not receive radiation therapy (hazard ratio: 3.574; 95% CI: 1.501-8.510; P = .002).

Conclusion:

Photodynamic therapy is an effective method for advanced esophageal cancer. The side effects are mild, and the short-term effect is good, especially in the relief of dysphagia. Photodynamic therapy can prolong the survival of patients with advanced esophageal cancer, and the Karnofsky Performance Status score and previous radiation therapy have a significant effect on the overall survival.

Repeated talaporfin sodium photodynamic therapy for esophageal cancer: safety and efficacy

BACKGROUND

Talaporfin sodium photodynamic therapy (tPDT) is an effective salvage treatment for local failure after chemoradiotherapy for esophageal cancer. Repeated tPDT could also be indicated for local recurrence or residue after the first salvage tPDT. However, the safety and efficacy of repeated tPDT have not been elucidated.

METHODS

We reviewed 52 patients with esophageal cancer who were treated with the first tPDT at Kyoto University Hospital between October 2015 and April 2020.

RESULTS

Among 52 patients, repeated tPDT after the first tPDT was indicated for 13 patients (25%), of which six had residual tumor, four had local recurrence after complete response (CR) after the first tPDT at the primary site, and six had metachronous lesion. The total session of repeated tPDT was 25; 16 were for primary sites and nine were for metachronous sites. Among them, six patients (46.2%) achieved local (L)-CR and nine lesions (56.3%) achieved lesion L-CR. By session, 10 sessions (40%) achieved L-CR. There were no severe adverse events except for one patient; this patient showed grade 3 esophageal stenosis and perforation after the third tPDT on the same lesion that was previously treated with porfimer sodium photodynamic therapy four times.

CONCLUSION

Repeated tPDT could be an effective and safe treatment for local failure even after salvage tPDT for esophageal cancer.

Review of early endoscopic findings in patients with local recurrence after definitive chemoradiotherapy for esophageal squamous cell carcinoma

BACKGROUNDS

Local recurrence after definitive chemoradiotherapy, if diagnosed early, can be cured by salvage endoscopic therapy, which allows organ preservation and contributes to maintaining patient quality of life. This study aimed to investigate early endoscopic findings of local recurrence in post-definitive chemoradiotherapy patients.

METHODS

Between January 2008 and June 2012, 17 esophageal squamous cell carcinoma patients with no metastasis but local recurrence after definitive chemoradiotherapy were enrolled. We attempted to find endoscopic hallmarks suggestive of local recurrence by comparing pre- and post-local recurrence diagnostic images. The influence of follow-up schedule on chosen salvage therapy type was also investigated.

RESULTS

Endoscopic local recurrence findings included eight submucosal tumors, five ulcers, and four erosions. Upon review of prior images, findings suggestive of local recurrence were detected in seven patients, including six submucosal tumors and one erosion, all of which were smaller than 10 mm. These lesions had changed morphologically at local recurrence diagnosis: three submucosal tumors had become larger and three submucosal tumors and one erosion had changed to ulcers. Of 12 patients with cT1 at local recurrence, four (33%) underwent follow-up endoscopy within 1 month of local recurrence findings and 11 patients (92%) were treated with salvage endoscopic therapy.

CONCLUSIONS

Endoscopists should be aware that SMTs or erosions, even those smaller than 10 mm, can indicate local recurrence after complete response to definitive chemoradiotherapy. Follow-up endoscopy should be performed within 1-2 months if findings suggestive of local recurrence are observed on prior endoscopy, even when biopsy results are negative.

Clinical application of the mirror irradiation technique in photodynamic therapy for malignant glioma

BACKGROUND

Intraoperative photodynamic therapy (PDT) using talaporfin sodium for malignant glioma is effective both in the experimental and in the clinical setting. Because the irradiation unit is fixed to the objective lens of the operating microscope, blind spots for irradiation exist. To overcome this problem, we developed a mirror reflecting system using a modified dental mirror.

METHODS

The developed mirror is made of stainless steel, has a mirror-polished surface, and is rhodium coated on 1 side, which is the reflecting surface. The reflection rate was measured using He-Ne laser irradiation. The reflection intensity was measured using a laser power meter when the incident angle to the mirror was changed to 60°, 45°, and 30°, and the reflectance was calculated by the direct received light intensity from the laser. After confirming the safety of the fundamental experiment, PDT was performed with this developed mirror on 9 patients with malignant glioma (4 with recurrence and 5 newly diagnosed).

RESULTS

The energy efficiency of the mirror was approximately 70 %, and apparent irregular reflection was not observed. Even during clinical use, apparent complications, such as irregular reflection, did not occur upon using the mirror in any of the patients. In all patients, recurrence did not occur in the site where mirror irradiation was performed, but in a deep site or a distant site to which sufficient laser irradiation did not reach.

CONCLUSION

PDT using our newly developed mirror involves few instrumental changes compared with the conventional irradiation method, and is effective, safe, and inexpensive.

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.

Photodynamic Therapy Using Talaporfin Sodium for Local Failure after Chemoradiotherapy or Radiotherapy for Esophageal Cancer: A Single Center Experience

A phase II study of second-generation photodynamic therapy (PDT) using talaporfin sodium has shown excellent treatment results for esophageal cancer with local failure after chemoradiotherapy (CRT) or radiotherapy (RT). However, only a few studies have reported this therapy in clinical practice. This study aimed to confirm the efficacy and safety of salvage PDT using talaporfin sodium for esophageal cancer in various clinical situations. Twelve patients with esophageal cancer with local failure after definitive CRT or RT who underwent PDT using talaporfin sodium were enrolled from April 2016 to January 2020. Overall, 10 patients (83.3%) achieved a local complete response. No skin phototoxicity was observed, but esophageal stricture occurred in five patients (41.7%). Esophageal stricture was improved with endoscopic balloon dilation in all patients, and subsequent analysis found no significant factors causing esophageal stricture after PDT. Two patients with synchronous tumors were successfully rescued by combination therapy with endoscopic submucosal dissection. Two patients with carcinoma in situ of larger than 1/2 circumference were rescued by repeated PDT. The 2-year overall survival was 80.0% (95% confidence interval 0.409–0.946). PDT using talaporfin sodium was an effective and safe salvage treatment for esophageal cancer with local failure after CRT or RT in various clinical situations.

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.

Experience of using photodynamic therapy in the treatment of esophageal cancer

Photodynamic therapy (PDT) is a worthy alternative to surgical esophageal resection or endoscopic mucosal resection and dissection (EMR, ESD) in patients with superficial esophageal cancer with severe concomitant diseases as well as in patients with a common form of esophageal cancer with severe malignant dysphagia. Patients with superficial (7) and advanced (15) esophageal cancer received PDT as an independent method and as a supplement to complex treatment. Radachlorin was used as a photosensitizer at a dose of 0.6–0.8 mg/kg, administered intravenously 3 hours before irradiation. A PDT session was carried out using a laser with a wavelength of 662 nm. The light dose used was 150–300 J/cm2 . The use of PDT made it possible to achieve the full effect in 7 (100%) patients in the group of superficial (T1a-T1b) esophageal cancer where PDT was either the only method of treatment or in combination with radiation therapy. In the group of patients with stenotic cancer the use of PDT made it possible to achieve full recovery of food intake after recanalization for 20% of patients, and partial – for 66.7%. Thus, complete natural food intake was restored for 86.7% of patients which improved their quality of life. PDT is also a method of choice for cancer of the upper esophagus as esophageal stenting in this situation can cause unwanted subjective sensations. 

Endoscopic Treatment of Early-Stage Esophageal Cancer

PURPOSE OF REVIEW

Esophageal cancer is a leading cause of global cancer-related mortality. Here, we discuss the major endoscopic treatment modalities for management of early esophageal cancer (EEC).

RECENT FINDINGS

Advances in endoscopic imaging and therapy have shifted the paradigm of managing early esophageal cancers. Though esophagectomy remains the preferred management for advanced cancers, guidelines now recommend endoscopic resection followed by ablative therapy for early (Tis and T1a) cancers. Available data suggests endoscopic treatment is comparable to surgery with regard to overall and cancer-specific survival with lower procedural morbidity and mortality. Endoscopic modalities are emerging as frontline treatment options for patients with early esophageal cancers. Accurate clinical staging with assessment of disease extent, tumor grade, and risk of nodal metastases is crucial when determining eligibility for endoscopic management of EEC. High-quality routine surveillance endoscopy is critical in patients who have undergone resection and/or ablation.

A multicenter phase II study of salvage photodynamic therapy using talaporfin sodium (ME2906) and a diode laser (PNL6405EPG) for local failure after chemoradiotherapy or radiotherapy for esophageal cancer

Photodynamic therapy (PDT) showed promising efficacy for local failure after chemoradiotherapy (CRT) for esophageal cancer. However, PDT required long sun shade period. This study aimed to evaluate the safety and efficacy of PDT using second generation photosensitizer, talaporfin sodium for local failure after CRT. This was the multi-institutional non-randomized phase II study. Patients with histologically proven local failure limited within the muscularis propria after 50Gy or more radiotherapy (RT) for esophageal cancer were eligible. We set the primary endpoint as local complete response (L-CR) per patients. And, secondary endpoints were confirmed L-CR, local progression free survival (L-PFS), progression free survival (PFS), overall survival (OS), L-CR per lesions (Lesion L-CR), and confirmed Lesion L-CR. The PDT procedure commenced with intravenous administration of a 40 mg/m² dose of talaporfin sodium followed by diode laser irradiation at a 664 nm wavelength. 26 eligible patients were enrolled and all were treated with PDT. Twenty three patients with 25 lesions were assessed L-CR after PDT; the L-CR rate per patients was 88.5% (95% CI: 69.8%-97.6%). No skin phototoxicity was observed, and no grade 3 or worse non-hematological toxicities related to PDT were observed. PDT using talaporfin sodium and a diode laser is a safe and curative salvage treatment for local failure after CRT or RT for patients with esophageal cancer.

Endoscopic diagnosis and treatment of early esophageal squamous neoplasia

Esophageal cancer is one of the leading causes of cancer-related death and is associated with high morbidity and mortality. It carries a poor prognosis as more than half of patients present with advanced and unresectable disease. One contributing factor is the increased risk of lymph node metastases at early stages of disease. As such, it is essential to detect squamous cell neoplasia (SCN) at an early stage. In order to risk stratify lesions, endoscopists must be able to perform image enhanced endoscopy including magnification and Lugol’s chromoendoscopy. The assessment of both the horizontal extent and depth of any lesion is also of utmost importance prior to treatment. Endoscopic mucosal resection and submucosal dissection remain the standard of care with literature supportive their respective use. Radiofrequency ablation and other endoscopic treatments are currently available although should not be considered first line at this time. Our objective is to review the current options for the endoscopic diagnosis and treatment of esophageal SCN.

Antibacterial photosensitization through activation of coproporphyrinogen oxidase

Gram-positive bacteria cause the majority of skin and soft tissue infections (SSTIs), resulting in the most common reason for clinic visits in the United States. Recently, it was discovered that Gram-positive pathogens use a unique heme biosynthesis pathway, which implicates this pathway as a target for development of antibacterial therapies. We report here the identification of a small-molecule activator of coproporphyrinogen oxidase (CgoX) from Gram-positive bacteria, an enzyme essential for heme biosynthesis. Activation of CgoX induces accumulation of coproporphyrin III and leads to photosensitization of Gram-positive pathogens. In combination with light, CgoX activation reduces bacterial burden in murine models of SSTI. Thus, small-molecule activation of CgoX represents an effective strategy for the development of light-based antimicrobial therapies.

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.

Interventional Therapy of Esophageal Cancer

Esophageal cancer (EC) is the fourth leading cause of cancer death in China. Despite a lot of advances in diagnosis and therapy, the survival rate of patients with EC is low. There is urgent need for a variety of methods and techniques to improve the survival time and alleviate the lesions of EC. Nowadays, alternative and less invasive approaches to the treatment of ECs are being identified. Here, we review several main interventional methods at different stages of EC, including endoscopic resection, stent placement, arterial infusion, photodynamic therapy, and radiofrequency ablation. This review will focus on the indications, methods, clinical outcomes, and complications of these methods, which may help guide the way forward.