Photodynamic therapy for cancers: a clinical trial of porfimer sodium in Japan

Ultrasound imaging guided targeted sonodynamic therapy enhanced by magnetophoretically controlled magnetic microbubbles

Sonodynamic therapy (SDT) utilizes ultrasonic excitation of a sensitizer to generate reactive oxygen species (ROS) to destroy tumor. Two dimensional (2D) black phosphorus (BP) is an emerging sonosensitizer that can promote ROS production to be used in SDT but it alone lacks active targeting effect and showed low therapy efficiency. In this study, a stable dispersion of integrated micro-nanoplatform consisting of BP nanosheets loaded and Fe3O4 nanoparticles (NPs) connected microbubbles was introduced for ultrasound imaging guided and magnetic field directed precision SDT of breast cancer. The targeted ultrasound imaging at 18 MHz and efficient SDT effects at 1 MHz were demonstrated both in-vitro and in-vivo on the breast cancer. The magnetic microbubbles targeted deliver BP nanosheets to the tumor site under magnetic navigation and increased the uptake of BP nanosheets by inducing cavitation effect for increased cell membrane permeability via ultrasound targeted microbubble destruction (UTMD). The mechanism of SDT by magnetic black phosphorus microbubbles was proposed to be originated from the ROS triggered mitochondria mediated apoptosis by up-regulating the pro-apoptotic proteins while down-regulating the anti-apoptotic proteins. In conclusion, the ultrasound theranostic was realized via the magnetic black phosphorus microbubbles, which could realize targeting and catalytic sonodynamic therapy.

Photodynamic therapy with talaporfin sodium for endoscopically unresectable gastric cancer using a novel simultaneous light-emitting method

We describe a case of gastric cancer treated by photodynamic therapy (PDT) with talaporfin sodium using a novel simultaneous light-emitting method. An 82-year-old man was diagnosed with gastric cancer near the cardia with suspected deep submucosal invasion. Surgical resection was deemed high-risk owing to an underlying pulmonary disease. After ruling out endoscopic procedures due to intense fibrosis resulting from the scarring, PDT with talaporfin sodium was chosen. PDT was successfully conducted using an endoscope with simultaneous light emission. The patient experienced a complete response to the treatment and showed no signs of recurrence during follow-up. This case highlights the potential of PDT with talaporfin sodium as a viable alternative for challenging cases, particularly in patients unsuitable for surgery and endoscopic resection. Furthermore, the novel simultaneous light-emitting method may improve the efficiency of the procedure. This case demonstrates the potential of PDT in gastric cancer treatment, especially for high-risk patients.

Photodynamic Therapy: Current Trends and Potential Future Role in the Treatment of Bladder Cancer

Bladder cancer (BC) is the 10th most common cancer in the world. The therapeutic spectrum of BC is broad and is constantly expanding. Despite the wide clinical use of photodynamic diagnosis (PTD) for BC, PDT has not been sufficiently investigated in the treatment landscape of BC. We performed an online search of the PubMed database using these keywords: photodynamic therapy, bladder cancer, urothelial carcinoma, in vivo, in vitro, cell line, animal model. Reviews, case reports, and articles devoted to photodynamic diagnostics and the photodynamic therapy of tumors other than urothelial carcinoma were excluded. Of a total of 695 publications, we selected 20 articles with clinical data, 34 articles on in vivo PDT, and 106 articles on in vitro data. The results presented in animal models highlight the potential use of PDT in the neoadjuvant or adjuvant setting to reduce local recurrence in the bladder and upper urinary tracts. Possible regimens include the combination of PDT with intravesical chemotherapy for improved local tumor control or the integration of vascular-targeted PDT in combination with modern systemic drugs in order to boost local response. We summarize available evidence on the preclinical and clinical application of PDT for urothelial carcinoma in order to explain the current trends and future perspectives.

The "Light Knife" for Gastric Cancer: Photodynamic Therapy

Photodynamic therapy (PDT) has been used clinically to treat cancer for more than 40 years. Some solid tumors, including esophageal cancer, lung cancer, head and neck cancer, cholangiocarcinoma, and bladder cancer, have been approved for and managed with PDT in many countries globally. Notably, PDT for gastric cancer (GC) has been reported less and is not currently included in the clinical diagnosis and treatment guidelines. However, PDT is a potential new therapeutic modality used for the management of GC, and its outcomes and realization are more and more encouraging. PDT has a pernicious effect on tumors at the irradiation site and can play a role in rapid tumor shrinkage when GC is combined with cardiac and pyloric obstruction. Furthermore, because of its ability to activate the immune system, it still has a specific effect on systemic metastatic lesions, and the adverse reactions are mild. In this Review, we provide an overview of the current application progress of PDT for GC; systematically elaborate on its principle, mechanism, and the application of a new photosensitizer in GC; and focus on the efficacy of PDT in GC and the prospect of combined use with other therapeutic methods to provide a theoretical basis for clinical application.

Photomedicine based on heme-derived compounds

Photoimaging and phototherapy have become major platforms for the diagnosis and treatment of various health complications. These applications require a photosensitizer (PS) that is capable of absorbing light from a source and converting it into other energy forms for detection and therapy. While synthetic inorganic materials such as quantum dots and gold nanorods have been widely explored for their medical diagnosis and photodynamic (PDT) and photothermal (PTT) therapy capabilities, translation of these technologies has lagged, primarily owing to potential cytotoxicity and immunogenicity issues. Of the various photoreactive molecules, the naturally occurring endogenous compound heme, a constituent of red blood cells, and its derivatives, porphyrin, biliverdin and bilirubin, have shown immense potential as noteworthy candidates for clinically translatable photoreactive agents, as evidenced by previous reports. While porphyrin-based photomedicines have attracted significant attention and are well documented, research on photomedicines based on two other heme-derived compounds, biliverdin and bilirubin, has been relatively lacking. In this review, we summarize the unique photoproperties of heme-derived compounds and outline recent efforts to use them in biomedical imaging and phototherapy applications.

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.

Recent Progress in the Theranostics Application of Nanomedicine in Lung Cancer

Lung cancer is one of the leading causes of cancer-related death worldwide. Non-small cell lung cancer (NSCLC) causes around 80% to 90% of deaths. The lack of an early diagnosis and inefficiency in conventional therapies causes poor prognosis and overall survival of lung cancer patients. Recent progress in nanomedicine has encouraged the development of an alternative theranostics strategy using nanotechnology. The interesting physico-chemical properties in the nanoscale have generated immense advantages for nanoparticulate systems for the early detection and active delivery of drugs for a better theranostics strategy for lung cancer. This present review provides a detailed overview of the recent progress in the theranostics application of nanoparticles including liposomes, polymeric, metal and bio-nanoparticles. Further, we summarize the advantages and disadvantages of each approach considering the improvement for the lung cancer theranostics.

Photodynamic therapy versus endoscopic submucosal dissection for management of patients with early esophageal neoplasia: a retrospective study

Background

Photodynamic therapy (PDT) and endoscopic submucosal dissection (ESD) have been proposed as a treatment for early esophageal neoplasia. The objective of this study is to compare between the clinical outcome after ESD and PDT to reach the best management for early esophageal neoplasia.

Methods

All patients undergoing ESD or PDT for early esophageal neoplasia between 2014 and 2015 were eligible for the study. A retrospective analysis for comparison between the results of ESD and PDT was done.

Results

36 patients underwent ESD and Thirty PDT. No significant difference was found between the two groups regarding the demographic or pathologic data. Also, there was no significant difference regarding the length of hospital stay, presence of hydrothorax, fever, and pain. Operative time was significantly longer in ESD than in PDT (72 vs. 8 minutes, P<0.001). In addition, bleeding was significantly lower in ESD than PDT (12 vs. 2, P<0.05). There was a significant difference regarding stricture and cost which were less in ESD (6 vs. 15, P<0.05). However, perforation was much more in ESD (6 vs. 0, P<0.05). There was no significant difference between the two groups regarding the disease free survival (DFS), but it was observed that patients who underwent PDT had more favorable 2-year DFS rates than patients received ESD.

Conclusions

The PDT may be comparable to the ESD. With the exception of esophageal stenosis, PDT could reduce many complications and have longer DFS in comparison with ESD. PDT is feasible for patients with early esophageal neoplasia confined to the mucosal layer without regional lymph nodal or distant metastasis.

Nursing care management of photodynamic therapy in digestive tract carcinomas at a single cancer center

The primary goal of nursing care in cases of endoscopic photodynamic therapy (PDT) for digestive tract carcinoma is to prevent phototoxicity by the intravenous administration of photosensitizers. The adequate protocol and management of patients should be conducted under the instruction of expert physicians. Our experiences of administering porfimer sodium and talaporfin sodium during clinical PDT provide insight regarding the specific management protocol of each photosensitizer during an in-hospital stay. We herein report our nursing protocol based on 15 years of experience. Under adequate management, PDT can be safely performed.

Photodynamic Therapy in Non-Gastrointestinal Thoracic Malignancies

Photodynamic therapy has a role in the management of early and late thoracic malignancies. It can be used to facilitate minimally-invasive treatment of early endobronchial tumours and also to palliate obstructive and bleeding effects of advanced endobronchial tumours. Photodynamic therapy has been used as a means of downsizing tumours to allow for resection, as well as reducing the extent of resection necessary. It has also been used successfully for minimally-invasive management of local recurrences, which is especially valuable for patients who are not eligible for radiation therapy. Photodynamic therapy has also shown promising results in mesothelioma and pleural-based metastatic disease. As new generation photosensitizers are being developed and tested and methodological issues continue to be addressed, the role of photodynamic therapy in thoracic malignancies continues to evolve.

Preclinical validation of talaporfin sodium-mediated photodynamic therapy for esophageal squamous cell carcinoma

Photodynamic therapy (PDT) kills cancer cells via a photochemical reaction mediated by an oncotropic photosensitizer. Herein, we performed an experimental preclinical study to validate the anti-tumour effect of talaporfin sodium-mediated PDT (t-PDT) for esophageal squamous cell carcinoma (ESCC) cells. We used human ESCC cells derived from various differentiation grades or resistant to 5-fluorouracil (5-FU). The cytotoxic effect of t-PDT was determined by evaluating cell viability, apoptosis and generation of reactive oxygen species (ROS) and DNA double-strand breaks. Furthermore, the anti-tumour effect of t-PDT was assessed using an anchorage-independent cell-growth assay and xenograft transplantation models. t-PDT induced potent cytotoxicity in ESCC cells independent of their differentiation grade or 5-FU resistance. Moreover, t-PDT induced robust apoptosis, as indicated by cell shrinkage, perinuclear vacuolization, nuclear fragmentation and induction of annexin V-positive cells. This apoptotic response was accompanied by concurrent activation of ROS, and induction of DNA double-strand breakage. Importantly, t-PDT suppressed efficiently anchorage-independent cell growth as well as ESCC-xenografted tumor formation. In aggregate, t-PDT showed anti-tumor potential for ESCC cells with various histological grades or chemoresistance, providing a novel translational rationale of t-PDT for the treatment of ESCC.

Can a less radical surgery using photodynamic therapy with acridine orange be equal to a wide-margin resection?

BACKGROUND

Wide-margin resections are an accepted method for treating soft tissue sarcoma. However, a wide-margin resection sometimes impairs function because of the lack of normal tissue. To preserve the normal tissue surrounding a tumor, we developed a less radical (ie, without a wide margin) surgical procedure using adjunctive photodynamic therapy and acridine orange for treating soft tissue sarcoma. However, whether this less radical surgical approach increases or decreases survival or whether it increases the risk of local recurrence remains uncertain.

QUESTIONS/PURPOSES

We determined the survival, local recurrence, and limb function outcomes in patients treated with a less radical approach and adjunctive acridine orange therapy compared with those who underwent a conventional wide-margin resection.

METHODS

We treated 170 patients with high-grade soft tissue sarcoma between 1999 and 2009. Fifty-one of these patients underwent acridine orange therapy. The remaining 119 patients underwent a conventional wide-margin resection for limb salvage surgery. We recorded the survival, local recurrence, and functional score (International Society of Limb Salvage [ISOLS]) score) for all the patients.

RESULTS

The 10-year overall survival rates in the acridine orange therapy group and the conventional surgery group were 68% and 63%, respectively. The 10-year local recurrence rate was 29% for each group. The 5-year local recurrence rates for Stages II, III, and IV were 8%, 36%, and 40%, respectively, for the acridine orange group and 13%, 27%, and 33%, respectively, for the conventional surgery group. The average ISOLS score was 93% for the acridine orange group and 83% for the conventional therapy group.

CONCLUSION

Acridine orange therapy has the potential to preserve limb function without increasing the rate of local recurrence. This therapy may be useful for eliminating tumor cells with minimal damage to the normal tissue in patients with soft tissue sarcoma.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of the levels of evidence.

Long-term observation of 64 patients with roentgenographically occult lung cancer treated with external irradiation and intraluminal irradiation using low-dose-rate iridium

OBJECTIVE

Therapeutic results of intraluminal irradiation were analyzed in 64 patients with roentgenographically occult lung cancer (ROLC).

METHODS

The subjects were 64 patients who underwent intraluminal irradiation between 1987 and 2003. Radiotherapy was performed by combining external irradiation with intraluminal irradiation using low-dose-rate iridium (four 370-MBq wires) through a catheter with a spacer. The doses of radiation were 0-70 Gy (median value 46 Gy) by external irradiation and 10-60 Gy (median value 29.3 Gy) by intraluminal irradiation.

RESULTS

The therapeutic effect was CR in 63 patients and PR in 1 patient, and local recurrence was observed in a PR case and in seven of the 63 patients who showed CR. The 5-year overall and relapse-free survival rates were 56 (95% CI, 43-69%) and 55% (95% CI, 43-68%), respectively. Fatal pulmonary hemorrhage was observed in one case.

CONCLUSIONS

Considering the facts that ROLC often occurs as multiple cancers and that many patients with ROLC have reduced lung function, radiation therapy by a combination of intraluminal and external irradiation may replace surgery as the first choice for the treatment of this disease.

Higher irradiance and photodynamic therapy for age-related macular degeneration (an AOS thesis)

PURPOSE

Photodynamic therapy (PDT) using verteporfin was the first pharmacologic therapy for neovascular age-related macular degeneration and changed the treatment paradigm for a major, blinding disease. The experimental work in the nonhuman primate was essential in developing treatment parameters for verteporfin PDT that could successfully occlude choroidal neovascularization with limited injury to the neural retina. Early in the preclinical primate studies, we hypothesized that higher irradiances could be used for ocular PDT than had been used in dermatology and other applications, which typically utilized an irradiance of 150 to 200 mW/cm(2). We set out to test the feasibility of irradiances up to 1800 mW/cm(2).

METHODS

PDT was applied to normal monkey eyes using verteporfin/benzoporphyrin derivative (BPD) (2 mg/kg) mixed with low-density lipoprotein in DMSO, and 692-nm light, with a spot size 1250mum, fluence approximately 50 J/cm(2), and irradiance varying from 150 (treatment time, 6 minutes) to 1800 mW/cm(2) (treatment time, 30 seconds). Photocoagulation lesions were applied using 514-nm and 692-nm laser light without drug, with irradiance of 18,750 to 200,000 mW/cm(2) and spot size of 500 mum. Treatment effect was evaluated by fundus photography, angiography, and light and electron microscopy with collagen denaturation as a marker of thermal injury.

RESULTS

Verteporfin/BPD PDT at irradiances of 150 to 1800 mW/cm(2) showed no collagen denaturation in contrast to photocoagulation lesions without dye (irradiance 10-fold and higher).

CONCLUSIONS

Verteporfin PDT could safely be performed at higher irradiances, permitting a clinically practical therapy. Ultimately, clinical trials demonstrated that verteporfin PDT could limit moderate vision loss in neovascular age-related macular degeneration. Although anti-VEGF therapy has replaced PDT as a first-line therapy, PDT may still have a role, perhaps in combination therapies. Further investigations to optimize drug delivery and to better understand the molecular mechanisms of PDT effects in both choroidal neovascularization and retina will improve its application in macular diseases.

Interstitial photodynamic therapy with rotating and reciprocating optical fibers

BACKGROUND

Photodynamic therapy (PDT) is an effective treatment modality that allows selective destruction of malignant tumor cells. However, because of the difficulty in exposing deeper areas of tumors, the modality has strictly limited indications. In this study, the authors introduce a new method for delivering laser light to a three-dimensional, wide area with the purpose of improving the therapeutic value of PDT.

METHODS

Three patients with squamous cell carcinoma of the tongue were treated with the present course. After administering porfimer sodium, laser-proof tubes were inserted through the tumor, and optical fibers were passed through the tubes. Pulse laser was emitted from the obliquely prepared fiber tip and distributed toward the target area while rotating and reciprocating the optical fiber.

RESULTS

Two patients achieved a complete response without any complications or functional disabilities. The third patient, however, had a partial response and required surgery.

CONCLUSIONS

The results indicate the capability of distributing laser light to an entire area of solid tumor. However, the ideal dose of laser light for the treatment of tumors remains unknown. Interstitial PDT will be more efficacious and reliable after the dosimetry is established.

External irradiation and intraluminal irradiation using middle-dose-rate iridium in patients with roentgenographically occult lung cancer

PURPOSE

Therapeutic results were analyzed in 39 patients with roentgenographically occult lung cancer (ROLC), and the significance and optimal dose of this therapy were evaluated.

METHODS AND MATERIALS

The subjects were 39 patients who underwent intraluminal irradiation between May 1987 and August 1999. Radiotherapy was performed by combining external irradiation with intraluminal irradiation using middle-dose-rate iridium (four 370-MBq wires) through a catheter with a spacer, which held the source in the center of the bronchus. The doses of radiation were 22-66 Gy (median value 45 Gy) by external irradiation and 10-46 Gy (median value 28 Gy) by intraluminal irradiation.

RESULTS

The therapeutic effect was CR in 38 patients and PR in 1, and local recurrence was observed in a PR case and 3 of the 38 patients who showed CR. The 3-year and 5-year relapse-free survival rates were both 87%. No severe radiation injury was observed.

CONCLUSIONS

Considering that ROLC often occurs as multiple cancers and that many patients with ROLC have reduced lung function, radiation therapy by a combination of intraluminal irradiation and external irradiation is expected to replace surgery as the first choice for the treatment of this disease in the twenty-first century.

Synthesis and photodynamic activity of a cationic zinc monoazaporphyrin bearing a nitrogen atom at the peripheral position

A new cationic monoazaporphyrin, zinc 2-aza-8,12,13,17-tetraethyl-2,3,7,18-tetramethylporphyrinium iodide 3 was synthesized. Photodynamic activity of 3 in degradation of 2',3'-isopropylideneguanosine 4 was compared with 2-aza-8,12,13,17-tetraethyl-3,7,18-trimethylporphyrin 1, zinc 2-aza-8,12,13,17-tetraethyl-3,7,18-trimethylporphyrin 2, and hematoporphyrin 5. The quarternary ammonium 3 showed a remarkable increase of photodynamic activity compared with 5, although no appreciable difference in the activity was observed between 1 and 5.

The treatment results of 40 patients with localized endobronchial cancer with external beam irradiation and intraluminal irradiation using low dose rate (192)Ir thin wires with a new catheter

BACKGROUND AND PURPOSE

While bronchial intraluminal irradiation is valued highly as a useful palliative treatment for lung cancer, its role as a curative treatment is unclear. The treatment results of 40 localized enbobronchial tumors (including tracheal cancer) who underwent external beam irradiation (EBR) and intraluminal irradiation (IR) as a curative treatment is reported, and the role of combined EBR and IR as a curative potential treatment is examined.

MATERIALS AND METHODS

Forty patients, including 22 with roentgenographically occult lung cancer (ROLC), 14 (18 lesions) with postoperative recurrent lung cancer (PORLC) and four with tracheal cancer, who underwent EBR and IR from February 1987 to August 1996, were studied. IR was conducted using low dose rate (1.48 GBq) (192)Ir thin wires at a bronchial mucosal dose of 4-6 Gy per fraction, with a total dose of 10-57 Gy (median 28 Gy). All patients were also given combined external Linac X-ray irradiation for a total dose of 30-77 Gy (median 52 Gy).

RESULTS

As for the primary effect, complete response (CR) was obtained in all 22 ROLC cases; CR was obtained in 12 (16 lesions), partial response (PR) in one and minor response (MR) in one of the PORLC cases; and CR was obtained in three and PR in one of the tracheal cancer cases. The 3-year and 5-year local control rate by Kaplan-Meier method was 75 and 65%, respectively. Twenty-two patients survived for 3 years or longer. Complications included one case each of fatal tracheal hemorrhage, bronchial mucosal ulcer and bronchial stenosis.

CONCLUSIONS

Combined EBR and IR is useful as a curative potential treatment, and long-term survival can be expected in ROLC, tracheal cancer and a portion of PORLC cases.

Photodynamic therapy for experimental tumors using ATX-S10(Na), a hydrophilic chlorin photosensitizer, and diode laser

ATX-S10(Na), a hydrophilic chlorin photosensitizer having an absorption maximum at 670 nm, is a candidate second-generation photosensitizer for use in photodynamic therapy (PDT) for cancer treatment. The effectiveness of PDT using ATX-S10(Na) and a diode laser for experimental tumors was evaluated in vitro and in vivo. In-vitro PDT using ATX-S10(Na) and the diode laser showed drug concentration-, laser dose- and drug exposure time-dependent cytotoxicity to various human and mouse tumor cell lines. In Meth-A sarcoma-implanted mice, optimal PDT conditions were found where tumors were completely eliminated without any toxicity. Against human tumor xenografts in nude mice, the combined use of 5 mg / kg ATX-S10(Na) and 200 J / cm(2) laser irradiation 3 h after ATX-S10(Na) administration showed excellent anti-tumor activity, and its efficacy was almost the same as that of PDT using 20 mg / kg porfimer sodium and a 100 J / cm(2) excimer dye laser 48 h after porfimer sodium injection. Microscopic observation of tumor tissues revealed that PDT using ATX-S10(Na) and the diode laser induced congestion, thrombus and degeneration of endothelial cells in tumor vessels, indicating that a vascular shutdown effect plays an important role in the anti-tumor activity of PDT using ATX-S10(Na) and the diode laser.

Neoadjuvant photodynamic therapy before curative resection of proximal bile duct carcinoma

BACKGROUND

Hilar bile duct carcinoma has an 80% probability of local recurrence after curative resection, which might be reduced if neoadjuvant photodynamic therapy is feasible. CASE AND TREATMENT: After intravenous injection of sodium porfimer we treated an adenocarcinoma of the proximal common bile duct (T2 N0 M0, Bismuth type II) in a 72-year-old man with red laser light (applied from the lumen at a dose 250 Joules/cm2), and the adjacent right and left hepatic and common bile duct at a dose of 125 Joules/cm2. After 23 days the tumor was completely resected (adenocarcinoma pT2 pNO; G2).

RESULTS

In the lumenal, 4-mm-thick layer the bile duct specimen exhibited complete tumor necrosis with pigmentation of photodegraded porfimer and no viable tumor cells, while in the outer layer of the wall (at 5-8-mm depth) viable cancer cell nests without degraded porfimer were seen. The bile duct tissue showed little damage. Eighteen months after surgery, neither tumor recurrence nor stricture formation was found at the pretreated bilioenteric anastomoses.

CONCLUSIONS

a) Photodynamic therapy with sodium porfimer seems to be confined to the superficial 4-mm layer of bile duct cancer. b) Neoadjuvant photodynamic therapy is feasible for hilar bile duct carcinoma.

The role of photodynamic therapy in the treatment of recurrent superficial bladder cancer

Photodynamic therapy is an exciting area of research for the treatment of superficial bladder cancer. Significant responses have been seen in patients resistant to standard intravesical treatments. New areas of research are focused on the development of new sensitizers and light distribution methods with less dermal and bladder toxicity.

In vitro study of biosynthesis of protoporphyrin IX induced by delta-aminolevulinic acid in normal and cancerous cells of the human cervix

BACKGROUND

delta-Aminolevulinic acid (ALA) is recognized as the starter in the biosynthesis of the heme group, the structural basis of cytochromes, chlorophylls, biliary pigments, and other porphyrins. It is the first intermediary in the biosynthesis of protoporphyrin IX (PpIX), and of the heme group. PpIX is present in low concentration in normal cells, and in high concentration in tumor cells.

METHODS

The accumulation of protoporphyrin IX (PpIX) induced by delta-aminolevulinic acid (ALA) was tested in two cervico-uterine cancer cell lines (HeLa and CaLo), and in normal human cervical epithelial (NHCE) cells.

RESULTS

The optimal concentration of ALA that induced maximum levels of intra- and extracellular accumulation of PpIX in both HeLa and NHCE cells was 300 micrograms of ALA/mL, and for CaLo cells, 150 micrograms/mL. The viability of HeLa, CaLo, and NHCE cells exposed to ALA measured 81, 98, and 84%, respectively. The optimal time for accumulation of PpIX, both intra- and extracellular, was 4 h for HeLa and NHCE cells and 5 h for CaLo cells per 24 h of exposure to optimal concentrations of ALA. After the maximum level of PpIX accumulation was reached, there was a gradual decrease until there was only a small quantity. A statistically significant difference (p < 0.0001) was found in the accumulation of PpIX, depending on the concentrations of ALA used as well as between cervical cancer cell lines and NHCE cells (p < 0.0001). The concentration ratio of PpIX for NHCE and HeLa cells was 1:7, and for NHCE and CaLo cells, 1:5.

CONCLUSIONS

These results are important for determining the usefulness of the sensitizer (PpIX).

Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin synthesis in patients with cervical intra-epithelial neoplasia

Photodynamic therapy (PDT), due to its tumor selectivity, represents an alternative approach to diagnose and treat cervical intra-epithelial neoplasia (CIN) without altering normal surrounding tissue. Our aim was to investigate the pharmacokinetics and the selectivity of 5-aminolevulinic acid (5-ALA)-induced porphyrin fluorescence after topical administration, to obtain basic clinical data for future diagnostic fluorescence imaging and PDT protocols for CIN. Twenty-eight non-pregnant women with a cytological diagnosis of low-grade or high-grade squamous intra-epithelial lesions were included. An aqueous solution containing 3% 5-ALA was topically applied 1 to 6 hrs prior to conization using a cervical cap. After excision, porphyrin-induced fluorescence was quantified in dysplastic (n = 14) and normal epithelium (n = 28) by means of quantitative fluorescence microscopy. High values of porphyrin fluorescence were found in squamous epithelium between 150 and 450 min, with a maximum at 300 min following administration of 5-ALA. Ratios of porphyrin fluorescence of dysplastic vs. surrounding normal epithelium were 1.3 and 1.21 for CIN 1 (n = 3) and CIN 2 (n = 3), respectively. In CIN 3 patients (n = 8), this ratio was 2.35; the best selectivity of 5-ALA-induced porphyrin fluorescence in CIN 3 lesions (ratio 3) was observed with a topical administration time of between 150 and 250 min. Our results demonstrate that patients with CIN 3 show higher 5-ALA-induced fluorescence compared with normal epithelium. The optimal administration time of topically applied 5-ALA was between 3 and 4 hr. Our data suggest that topical ALA-PDT and photodynamic diagnosis might be suitable for detecting CIN.

Photodynamic therapy for early stage bronchogenic carcinoma

Photodynamic therapy utilizing Photofrin has proved to be an effective modality that can be used in the treatment of a wide variety of solid tumors and luminal cancers. The effectiveness of photodynamic therapy (PDT) was demonstrated in our institution in 1980 for the treatment of lung cancers, and increasing attention has been focused on this new treatment technique. Over the past decade, 240 patients (283 lesions) with central type lung cancers have been treated in our hospital. Overall complete remission was obtained in 39.6% of the 112 lesions, partial remission in 59.4%, and no remission was obtained in 1.0%. However, among 95 early stage lesions, CR was obtained in 79 (83.2%) and 71 cases were disease free at 3 to 176 months. We conclude that PDT is efficacious in the treatment of superficial lung cancer where complete remission may be achieved.

Photodynamic therapy for cancer of the upper aerodigestive tract using tetra(m-hydroxyphenyl)chlorin

A major step in the development of photodynamic therapy (PDT) is the clinical optimization and evaluation of new photosensitizers (PS). Ideally, new compounds should be more effective and/or induce fewer side effects than the first generation PS such as hematoporphyrin derivative and Photofrin. We report the results of our study of PDT applied in the human upper aerodigestive tract, using tetra(m-hydroxyphenyl)chlorin (mTHPC) as the photosensitizing drug. Twenty-seven patients with early (i.e., in situ or microinvasive) squamous cell carcinomas and 4 patients with T1 or T2 cancers were studied. In most cases, illumination of the tumor was performed 4 days after i.v. injection of 0.15 mg/kg of mTHPC using 652 or 514 nm laser light. Of the 36 early tumors evaluated 30 (83%) showed no recurrence after a mean disease-free follow-up of 15.3 months (3-35 months). Of the T1 and T2 cancers, only one achieved a complete response. Major complications, all following red light illuminations, included 1 bronchial stenosis, 1 esophagotracheal fistula, and 2 probable occult perforations of the esophagus. PDT in the esophagus with green light renders such perforations essentially impossible, without, however, reducing the efficacy of the treatment. Skin photosensitization, never observed later than the first week after injection, was seen in 12 patients. In conclusion, photodynamic therapy with mTHPC is a safe and effective technique for the treatment of early carcinomas of the upper aerodigestive tract. Its efficacy is much lower for more advanced cancers.

In vitro studies on the potential use of 5-aminolaevulinic acid-mediated photodynamic therapy for gynaecological tumours

Results are reported on the sensitivity of various gynaecological tumour cell lines to 5-aminolaevulinic acid-induced protoporphyrin IX-sensitised photodynamic therapy (ALA-PDT) in vitro. All cell lines tested accumulated ALA-induced protoporphyrin IX (PpIX) and demonstrated good sensitivity to ALA-PDT. Localisation of PpIX in the mitochondria was demonstrated by fluorescence microscopy. Subcellular damage following ALA-PDT was observed using transmission electron microscopy. This damage was localised initially to the mitochondria, with damage to membranes and the nucleus and complete loss of intracytoplasmic organisation being observed subsequently. There was no apparent difference in ALA-PDT response between a multidrug-resistant ovarian carcinoma cell line and its parent line. These results indicate that ALA-PDT has potential for application to therapy of gynaecological malignancies.

Photodynamic therapy with porfimer sodium versus thermal ablation therapy with Nd:YAG laser for palliation of esophageal cancer: a multicenter randomized trial

BACKGROUND

Photodynamic therapy (PDT) is a different type of laser treatment from Nd:YAG thermal ablation for palliation of dysphagia from esophageal cancer.

METHODS

In this prospective, multicenter study, patients with advanced esophageal cancer were randomized to receive PDT with porfimer sodium and argon-pumped dye laser or Nd:YAG laser therapy.

RESULTS

Two hundred thirty-six patients were randomized and 218 treated (PDT 110, Nd:YAG 108) at 24 centers. Improvement in dysphagia was equivalent between the two treatment groups. Objective tumor response was also equivalent at week 1, but at month 1 was 32% after PDT and 20% after Nd:YAG (p < 0.05). Nine complete tumor responses occurred after PDT and two after Nd:YAG. Trends for improved responses for PDT were seen in tumors located in the upper and lower third of the esophagus, in long tumors, and in patients who had prior therapy. More mild to moderate complications followed PDT, including sunburn in 19% of patients. Perforations from laser treatments or associated dilations occurred after PDT in 1%, Nd:YAG 7% (p < 0.05). Termination of laser sessions due to adverse events occurred in 3% with PDT and in 19% with Nd:YAG (p < 0.05).

CONCLUSIONS

Photodynamic therapy with porfimer sodium has overall equal efficacy to Nd:YAG laser thermal ablation for palliation of dysphagia in esophageal cancer, and equal or better objective tumor response rate. Temporary photosensitivity is a limitation, but PDT is carried out with greater ease and is associated with fewer acute perforations than Nd:YAG laser therapy.

Endoscopic criteria of early squamous cell carcinoma of the bronchus

BACKGROUND

Early lung cancer, not extending beyond the bronchial cartilaginous layer without regional lymph node involvement is considered curable by endoscopic laser therapy or limited surgery. The endoscopic criteria for early squamous cell carcinoma of the bronchus, however, have not yet been determined.

METHODS

For 44 resected lesions of roentgenographically occult bronchogenic squamous cell carcinomas, the relationship between endoscopic findings and the degree of histologic extent of tumor was examined.

RESULTS

The lesions were divided into three types: polypoid or nodular (PN), flatly spreading (FS), and mixed. Thirty-three lesions arising from the central bronchus included 7, 19, and 7 of the PN, FS, and mixed types, respectively. In the central lesions, the degree of transmural invasion and the greatest dimension correlated, but the degree of intramural invasion of PN-type lesions was higher than that of the FS type. The PN-type lesions smaller than 10 mm and the FS type smaller than 15 mm in greatest dimension were found within the cartilaginous layer without regional lymph node involvement. All lesions of the mixed type were larger than 20 mm. Three of the lesions larger than 20 mm had regional lymph node involvement. All 11 lesions originating in the peripheral bronchus were of the FS type, and a lesion of only 5 mm in greatest dimension had extracartilaginous invasion.

CONCLUSIONS

The endoscopic criteria of early squamous cell carcinoma of the bronchus may be applied to central PN lesions smaller than 10 mm and central FS lesions less than 15 mm in greatest dimension. Any lesions of mixed type should be excluded from the criteria.