AUSTRALIAN AND NEW ZEALAND STUDY OF PHOTODYNAMIC THERAPY IN CHOROIDAL AMELANOTIC MELANOMA

The fusion of light and immunity: Advancements in photoimmunotherapy for melanoma

Metastatic melanoma is an aggressive skin cancer with high mortality and recurrence rates. Despite the clinical success of recent immunotherapy approaches, prevailing resistance rates necessitate the continued development of novel therapeutic options. Photoimmunotherapy (PIT) is emerging as a promising immunotherapy strategy that uses photodynamic therapy (PDT) to unleash systemic immune responses against tumor sites while maintaining the superior tumor-specificity and minimally invasive nature of traditional PDT. In this review, we discuss recent advances in PIT and strategies for the management of melanoma using PIT. PIT can strongly induce immunogenic cell death, inviting the concomitant application of immune checkpoint blockade or adoptive cell therapies. PIT can also be leveraged to selectively remove the suppressive immune populations associated with immunotherapy resistance. The modular nature of PIT therapy design combined with the potential for patient-specific antigen selection or drug co-delivery makes PIT an alluring option for future personalized melanoma care.

Combined photodynamic therapy and transpupillary thermotherapy for small choroidal melanoma

OBJECTIVE

The objective of this study was to determine whether combining verteporfin-based photodynamic therapy (PDT) and transpupillary thermotherapy (TTT) achieves adequate tumour control while maintaining visual acuity in individuals with small choroidal melanoma of amelanotic, melanotic, and variable pigmentation.

DESIGN

Individuals with posterior choroidal melanomas up to 3 mm in height underwent verteporfin-based PDT followed by immediate TTT. Further combined laser therapy was performed if a poor response was noted at 12 weeks or beyond. Tumours that demonstrated significant further growth were treated with brachytherapy or enucleation. A total of 37 eyes of 37 patients from the Terrace Eye Centre in Brisbane, Australia were studied. Average age of participants was 59.62 ± 12.45 years, and 17 of 37 participants were female (46%).

METHODS

This was a retrospective, noncomparative interventional study.

RESULTS

Seven of the 37 participants (19%) had recurrence of their tumour requiring further brachytherapy or enucleation. There was no statistically significant difference in visual acuity before and after treatment. There were no baseline characteristics that predicted treatment outcome. Ten individuals developed complications including epiretinal membrane (16%), scotoma (8%), cataract (3%), and macular edema (3%). No individuals experienced extraocular extension or progressed to metastatic disease. The mean follow-up time was 49 months.

CONCLUSION

Combined PDT and TTT achieved 81% tumour control in this study while preserving visual acuity. However, higher rates of local recurrence compared with brachytherapy warrant close follow-up to identify recurrences early.

Photodynamic Therapy for Eye, Ear, Laryngeal Area, and Nasal and Oral Cavity Diseases: A Review

Photodynamic therapy (PDT) has emerged as a promising modality for the treatment of various diseases. This non-invasive approach utilizes photosensitizing agents and light to selectively target and destroy abnormal cells, providing a valuable alternative to traditional treatments. Research studies have explored the application of PDT in different areas of the head. Research is focusing on a growing number of new developments and treatments for cancer. One of these methods is PDT. Photodynamic therapy is now a revolutionary, progressive method of cancer therapy. A very important feature of PDT is that cells cannot become immune to singlet oxygen. With this therapy, patients can avoid lengthy and costly surgeries. PDT therapy is referred to as a safe and highly selective therapy. These studies collectively highlight the potential of PDT as a valuable therapeutic option in treating the head area. As research in this field progresses, PDT may become increasingly integrated into the clinical management of these conditions, offering a balance between effectiveness and minimal invasiveness.

Factors affecting eye conservation and metastasis in posterior uveal melanomas

PURPOSE

To determine the effect of patient and tumor features and different treatments on eye removal (enucleation or exenteration) and metastasis in posterior uveal melanoma (PUM).

METHODS

Retrospective analysis. Patient age (≤60 vs >60 years), sex (female vs male), visual acuity (VA, ≤20/40 vs >20/40), largest tumor basal diameter (LTBD), tumor thickness, tumor stage according to American Joint Committee on Cancer (AJCC) 8th edition, ciliary body involvement, distance to optic disc (OD)/fovea (≤3 mm vs >3 mm), OD involvement, and histopathology were evaluated. Primary treatment options were transpupillary thermotherapy, plaque radiotherapy, Cyberknife radiosurgery, exoresection, and eye removal. Risk factors for primary eye removal were determined using logistic regression test and those for secondary eye removal and metastasis with Cox regression analysis.

RESULTS

Of 387 cases, 153 (39.5%) underwent primary eye removal. Multivariable risk factors for primary eye removal included AJCC tumor stage (p = 0.001, OR:4.586; p < 0.001, OR:34.545; p < 0.001, OR:103.468 for stages T2, T3, and T4 vs stage T1, respectively), and VA≤20/40 (p = 0.014, OR:2.597). Multivariable risk factors for secondary eye removal were VA≤20/40 (p = 0.019, RR:2.817) and AJCC stage T3 vs T1 (p = 0.021, RR:2.666). Eye preservation rates in patients undergoing eye-conserving treatments were 80.3%, 69.6%, and 51.5% at 5, 10, and 15 years, respectively. Metastasis-free survival rates were 81.0%, 73.0%, and 56.7% at 5, 10, and 15 years, respectively. Multivariable risk factors for metastasis included eye removal as primary treatment (p = 0.005, RR:2.828) and mixed type histopathology (p < 0.001, RR:4.804).

DISCUSSION

Early diagnosis is crucial for both eye preservation and survival in PUM. Increasing AJCC tumor stage and lower VA were risk factors for eye removal in this study. Mixed type histopathology and primary eye removal were risk factors for metastasis.

Spotlight on porphyrins: Classifications, mechanisms and medical applications

Photodynamic therapy (PDT) and sonodynamic therapy (SDT) are non-invasive treatment methods with obvious inhibitory effect on tumors and have few side effects, which have been widely concerned and explored by researchers. Sensitizer is the main factor in determining the therapeutic effect of PDT and SDT. Porphyrins, a group of organic compounds widespread in nature, can be activated by light or ultrasound and produce reactive oxygen species. Therefore, porphyrins as sensitizers in PDT have been widely explored and investigated for many years. Herein, we summarize the classical porphyrin compounds and their applications and mechanisms in PDT and SDT. The application of porphyrin in clinical diagnosis and imaging is also discussed. In conclusion, porphyrins have good application prospects in disease treatment as an important part of PDT or SDT, and in clinical diagnosis and imaging.

Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

Photodynamic therapy of primary and recurrent forms of weakly pigment choroidal melanoma

Treatment of poorly-pigmented tumors of small sizes can be carried out using photodynamic therapy (PDT). The material for the analysis was data on 112 patients. We used data from the Belarusian Cancer Registry, medical records of patients with clinically diagnosed choroid melanoma (C69.3 according to ICD-10) for the period 2013–2021. The size and level of blood flow in the tumors were assessed using an ultrasound machine with a doppler attachment. PDT was carried out using a «UPL PDT» semiconductor laser (Lemt, Republic of Belarus, λ=661 nm) with a light spot diameter of 1 to 3 mm for 60 s per field with a light dose of 50 J/cm2. The entire surface of the tumor was exposed to the action, with the fields “tiled”, from the periphery to the top of the tumor, with overlapping fields. Tumor pigmentation was assessed visually. To evaluate the treatment outcome, the general group of patients was divided into three subgroups according to thickness and basal diameter. Group I – 40 (35.7%) patients, with an average tumor thickness of 1.4±0.2 mm, basal diameter – 5.8±1.5 mm. II – 51 (45.5%) patients, with an average tumor thickness of 2.3 ± 0.3 mm, basal diameter – 7.9 ± 1.5 mm. III – 21 (18.8%) patients. The mean value of the tumor thickness was 3.8±0.4 mm, the basal diameter was 9.8±1.4 mm. After PDT in the general group (n=112), 29 (25.9%) patients had complete tumor resorption, and 83 (74.1%) patients had stabilization. The eyeball was saved in 107 (95.5%) patients. Continued growth and relapse were recorded in 34 patients: 25 (22.3%) and 9 (8.0%), respectively. In 29 (85.3%) patients, the eyeball was preserved after treatment of relapse and continued growth. 5 (4.5%) enucleations were performed. Adjusted one-year cumulative survival was 100%, 3-year and 5-year 95.8±2.4%, 93.7±3.1%, respectively

Photodynamic therapy (PDT) as adjuvant treatment to brachytherapy for amelanotic choroidal melanoma

PURPOSE

To evaluate the effect of photodynamic therapy (PDT) as adjuvant treatment, after brachytherapy, in posterior amelanotic choroidal melanomas.

METHODS

Six patients with posterior amelanotic choroidal melanoma underwent brachytherapy treatment. Tumour response was assessed by fundus examination, fundus photography and A-B scan ultrasonography. The residual tumours were treated with adjuvant PDT performed with infusion of verteporfin intravenously at 6 mg/m2 body surface area. Five minutes after infusion, a 689 nm laser was applied with a light dose of 100 J/cm2 over an interval of 166 s.

RESULTS

At a median follow-up after brachytherapy of 17.5 months (IQR 16.2-22.5, range 5-42 months), tumours showed a partial reduction of tumour thickness (22.5% as compared to baseline value) and persistent low internal reflectivity at A-B scan ultrasonography. Supplementary photodynamic treatment resulted in complete resolution of the lesion with marked decrease of elevation . Mean decrease in thickness after PDT was 49.9% with respect to previous brachytherapy treatment 22.5% (p = 0.007). The results was achieved within a median period of 4 months (range 2-4 months) after PDT, and there has been no recurrence after a median follow-up of 84.7 months ± 18.7 (range 59 to 107 months).

CONCLUSION

Combined treatment of brachytherapy and adjuvant PDT in amelanotic uveal melanoma seems to be favourable with regard to complete and rapid tumour regression.

Long non-coding RNA terminal differentiation-induced non-coding RNA regulates cisplatin resistance of choroidal melanoma by positively modulating extracellular signal-regulated kinase 2 via sponging microRNA-19b-3p

In the present study, we aimed to investigate the role of long non-coding RNA terminal differentiation-induced non-coding RNA (TINCR) in cisplatin (DDP) resistance of choroidal melanoma (CM) and the potential molecular mechanisms. CM and non-CM tissues were collected from 60 CM patients. DDP-resistant CM cells were obtained by selection with linearly increased DDP treatment. The expression levels of TINCR, microR-19b-3p (miR-19b-3p), and extracellular signal-regulated kinase 2 (ERK-2) were detected by quantitative real-time PCR. Cholecystokinin octapeptide (CCK-8) assay was utilized to detect chemosensitivity and cell viability. Flow cytometry analysis was performed to detect apoptotic cells. The protein levels of Bax, Bcl-2, cleaved-caspase-3, ERK-2, and nuclear factor-kappa B p65 were measured by Western blot. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were performed to determine the relationship among TINCR, miR-19b-3p, and ERK-2. The results showed that the levels of TINCR and ERK-2 were markedly increased in DDP-resistant CM tissues and cells, while miR-19b-3p level was significantly reduced. TINCR knockdown reduced DDP resistance and cell viability and promoted cell apoptosis, while TINCR overexpression exhibited opposite effects. TINCR and ERK-2 were direct targets of miR-19b-3p. Further experiments revealed that TINCR enhanced DDP resistance in CM cells by regulating the miR-19b-3p/ERK-2/NF-kb axis. Taken together, our study revealed a critical role of TINCR in regulating DDP resistance in CM and suggested that TINCR is a potential cisplatin-resistant CM therapeutic target.

Nanoparticle-Based Drug Delivery Systems for Photodynamic Therapy of Metastatic Melanoma: A Review

Metastatic melanoma (MM) is a skin malignancy arising from melanocytes, the incidence of which has been rising in recent years. It poses therapeutic challenges due to its resistance to chemotherapeutic drugs and radiation therapy. Photodynamic therapy (PDT) is an alternative non-invasive modality that requires a photosensitizer (PS), specific wavelength of light, and molecular oxygen. Several studies using conventional PSs have highlighted the need for improved PSs for PDT applications to achieve desired therapeutic outcomes. The incorporation of nanoparticles (NPs) and targeting moieties in PDT have appeared as a promising strategy to circumvent various drawbacks associated with non-specific toxicity, poor water solubility, and low bioavailability of the PSs at targeted tissues. Currently, most studies investigating new developments rely on two-dimensional (2-D) monocultures, which fail to accurately mimic tissue complexity. Therefore, three-dimensional (3-D) cell cultures are ideal models to resemble tumor tissue in terms of architectural and functional properties. This review examines various PS drugs, as well as passive and active targeted PS nanoparticle-mediated platforms for PDT treatment of MM on 2-D and 3-D models. The overall findings of this review concluded that very few PDT studies have been conducted within 3-D models using active PS nanoparticle-mediated platforms, and so require further investigation.

Photodynamic therapy for choroidal melanoma: What is the response rate?

To determine the response rate of choroidal melanoma following primary photodynamic therapy, we conducted a meta-analysis of published studies. A total of 7 studies reporting photodynamic therapy as primary treatment of choroidal melanoma in 162 patients with a mean tumor height of 2.8 mm (1.4 to 4.2) were identified. Forty-six percent of tumors were amelanotic, 48% were fully pigmented, and 6% had partial pigmentation. The photodynamic therapy parameters in all studies included 10-minute intravenous infusion of verteporfin (6 mg/m²), but varied in number of sessions (1 to 3), fluence (1× to 19×), and number of spots (single or multiple). The response was defined as tumor regression (partial or total) or lack of growth after initial treatment. The response to photodynamic therapy was predominantly observed as regression (126 [78%]). Overall response rate was 80% (mean) with a wide range among studies (58%-100%) over a period of 50 months (mean) with variable follow-up (range, 1-156 months). None of the studies reported progression- or recurrence-free survival; however, the recurrence rate was not related to the follow-up duration. Favorable prognostic factors were smaller size and lack of pigmentation. The overall response rate of 80% suggests that photodynamic therapy may be an effective primary treatment for small choroidal melanoma, especially in cases without pigmentation. Artifacts in study design (inclusion criteria and outcome measure) may have contributed to the variable observed response rate. Further studies with uniform inclusion criteria, standardized treatment parameters, well-defined outcome measures, and long follow-up are needed.

Long-term Outcomes of Small Pigmented Choroidal Melanoma Treated with Primary Photodynamic Therapy

PURPOSE

To report the long-term outcomes of patients with small, pigmented, posteriorly located choroidal melanoma undergoing primary treatment using photodynamic therapy (PDT) with verteporfin at the London Ocular Oncology Service.

DESIGN

Retrospective, interventional, consecutive case series.

PARTICIPANTS

All patients undergoing primary treatment using PDT with verteporfin from April 2014 to December 2015 and followed until December 2019.

METHODS

This is a long-term follow-up study of the same cohort of patients previously reported by our group in 2017 and 2018.

MAIN OUTCOME MEASURES

Local tumor control, visual outcomes, and metastasis-free survival.

RESULTS

Twenty-six patients were included with a mean (± standard deviation) age and tumor thickness of 62 ± 14 years and 1.3 ± 0.5 mm, respectively. Tumors were posteriorly located (mean distance to optic nerve and fovea = 2.0 ± 2.2 mm and 1.6 ± 1.5 mm, respectively), and the majority were fully pigmented (73%). Overall, patients were followed for a median (interquartile range [IQR], range) of 49.5 (15.3, 7.0-66.0) months from first PDT to last follow-up. Over the course of this study, 14 of 26 (54%) have developed a local recurrence at a median of 20.0 months (20.5, 4.7-60.9 months). The most common pattern of recurrence was an isolated increase in basal dimensions (9/14; 64%). Median (IQR) final logarithm of the minimum angle of resolution visual acuity of the whole cohort was 0.2 (0.5). The only statistically significant difference in baseline and outcome characteristics between treatment failures and nonfailures was the distance to the fovea (median [IQR], 0.5 [1.3] vs. 2.5 [2.8]; P = 0.002) and final logarithm of the minimum angle of resolution visual acuity (median [IQR], 0.50 [0.80] vs. 0.00 [0.14]; P = 0.002), respectively.

CONCLUSIONS

Although treatment of small pigmented posterior choroidal melanoma with PDT effectively preserves visual acuity, 5-year treatment-success calculated by Kaplan-Meier analysis was only 38.4%. Recurrences after PDT tend to occur along the tumor edges, often with minimal increase in thickness. Given the substantial risk of treatment failure, primary PDT with vertepofrin is recommended in exceptional cases of choroidal melanoma, for which other treatments with greater tumor control are not a feasible option.

Primary photodynamic therapy for small amelanotic choroidal melanomas: consecutive case series of 69 patients with at least 24-month follow-up

AIMS

To investigate the success and recurrence rates and visual outcomes in a large case series of amelanotic posterior choroidal melanomas treated by means of primary photodynamic therapy (PDT) with verteporfin.

METHODS

Retrospective case series from a single specialist ocular oncology centre. All patients had a clinical diagnosis of choroidal melanoma and were selected for PDT based on tumour characteristics. Included patients had at least 24 months of follow-up from initiation of treatment and all but one had not received treatment prior to PDT.

RESULTS

69 patients were included. Mean tumour thickness was 1.9 mm (range 0.5-4.4), while the mean basal diameter was 6.9 mm (range 2.4-11.0). Included lesions were stage cT1a (n=66) or cT2a (n=3). The mean duration of follow-up from treatment initiation was 57 months (range 24-116 months). Seven lesions (10%) failed to respond to PDT. 10 patients (16%) experienced recurrence during follow-up. Overall success rate in this series was 75% (n=52). 83% of successfully treated patients (n=43) maintained or gained vision by final follow-up. Visual outcomes were significantly better in those patients who received PDT therapy alone in comparison to those who needed other treatments for their melanoma (Fisher's exact test, p=0.004). Unfortunately, one patient (1.4%) in the series developed systemic metastases and died.

CONCLUSION

Selected amelanotic posterior uveal melanomas may be successfully treated with PDT with retention of good vision in the majority of cases, maintained with a mean of 57 months (minimum of 24 months) of follow-up.

Susceptibility and Resistance Mechanisms During Photodynamic Therapy of Melanoma

Melanoma is the most aggressive malignant skin tumor and arises from melanocytes. The resistance of melanoma cells to various treatments results in rapid tumor growth and high mortality. As a local therapeutic modality, photodynamic therapy has been successfully applied for clinical treatment of skin diseases. Photodynamic therapy is a relatively new treatment method for various types of malignant tumors in humans and, compared to conventional treatment methods, has fewer side effects, and is more accurate and non-invasive. Although several in vivo and in vitro studies have shown encouraging results regarding the potential benefits of photodynamic therapy as an adjuvant treatment for melanoma, its clinical application remains limited owing to its relative inefficiency. This review article discusses the use of photodynamic therapy in melanoma treatment as well as the latest progress made in deciphering the mechanism of tolerance. Lastly, potential targets are identified that may improve photodynamic therapy against melanoma cells.