The use of lasers in the treatment of skin cancer: A review

Self-Assembled BODIPY Derivative with A-D-A Structure as Organic Nanoparticles for Photodynamic/Photothermal Cancer Therapy

Organic nanomaterials have attracted considerable attention in the area of photodynamic and photothermal therapy, owing to their outstanding biocompatibility, potential biodegradability, well-defined chemical structure, and easy functionalization. However, it is still a challenge to develop a single organic molecule that obtains both photothermal and photodynamic effects. In this contribution, we synthesized a new boron-dipyrromethene (BODIPY)-based derivative (DPBDP) with an acceptor-donor-acceptor (A-D-A) structure by coupling 3,6-di(2-thienyl)-2,5-dihydropyrrolo [3,4-c] pyrrole-1,4-dione (DPP) and BODIPY. To enhance the hydrophilicity of the BODIPY derivative, the polyethylene glycol (PEG) chains were introduced to the meso- position of BODIPY core. The amphiphilic DPBDP was then self-assembled into related nanoparticles (DPBDP NPs) with improved hydrophilicity and enhanced absorbance in the NIR region. DPBDP NPs could simultaneously generate the singlet oxygen (¹O₂) and heat under the irradiation of a single laser (690 nm). The ¹O₂ quantum yield and photothermal conversion efficiency (PCE) of DPBDP NPs were calculated to be 14.2% and 26.1%, respectively. The biocompatibility and phototherapeutic effect of DPBDP NPs were evaluated through cell counting kit-8 (CCK-8) assay. Under irradiation of 690 nm laser (1.0 W/cm²), the half maximal inhibitory concentration (IC₅₀) of DPBDP NPs was calculated to be 16.47 µg/mL. Thus, the as-prepared DPBDP NPs could be acted as excellent candidates for synergistic photodynamic/photothermal therapy.

Interstitial Photothermal Therapy Generates Durable Treatment Responses in Neuroblastoma

Photothermal therapy (PTT) represents a promising modality for tumor control typically using infrared light-responsive nanoparticles illuminated by a wavelength-matched external laser. However, due to the constraints of light penetration, PTT is generally restricted to superficially accessible tumors. With the goal of extending the benefits of PTT to all tumor settings, interstitial PTT (I-PTT) is evaluated by the photothermal activation of intratumorally administered Prussian blue nanoparticles with a laser fiber positioned interstitially within the tumor. This interstitial fiber, which is fitted with a terminal diffuser, distributes light within the tumor microenvironment from the "inside-out" as compared to from the "outside-in" traditionally observed during superficially administered PTT (S-PTT). I-PTT improves the heating efficiency and heat distribution within a target treatment area compared to S-PTT. Additionally, I-PTT generates increased cytotoxicity and thermal damage at equivalent thermal doses, and elicits immunogenic cell death at lower thermal doses in targeted neuroblastoma tumor cells compared to S-PTT. In vivo, I-PTT induces significantly higher long-term tumor regression, lower rates of tumor recurrence, and improved long-term survival in multiple syngeneic murine models of neuroblastoma. This study highlights the significantly enhanced therapeutic benefit of I-PTT compared to traditional S-PTT as a promising treatment modality for solid tumors.

Development of a Customized Endoscopic Dual-Diffusing Optical Fiber Probe for Pancreatic Cancer Therapy: Toward Clinical Use

Objective: We developed a dual-diffusing optical fiber probe (DDOFP), capable of uniformly illuminating the anatomical structure of pancreatic duct for photodynamic therapy (PDT) of pancreatic cancer in clinical settings. Background: Optical fiber presents a unique route for pancreatic PDT by enabling access to the pancreatic duct. For effective pancreatic PDT, the optical fiber should produce a uniform illumination covering of the pancreatic duct, while maintaining its transmission property under thermomechanical stresses in surgical environments. Methods: The transmission profiles of DDOFP were measured using a charge-coupled device (CCD) camera at two directions: front-spherical and side-cylindrical areas of the optical fiber. We simulated the change in transmission property by curved tube structures using optically transparent phantom. DDOFP was integrated with 19-gauge needle catheter that is commercially used as an optical guide to treat pancreatic cancer. The temperature of DDOFP was measured at the end face using a thermistor probe in the bovine tissue, while delivering laser energy of over 200 and 500 J. Results: DDOFP was customized to secure the inner diameter of the 19-gauge needle catheter of 686 μm to be integrated as a clinical device. The round ball lens fiber tip minimized the back-burn effect caused by blood carbonization during surgery and induced front-spherical diffusion. DDOFP produced uniform light illumination with intensity difference of <10%. When DDOFP was bent with a small curvature <15 mm, the transmission intensity was consistent. Under high-power laser transmission, DDOFP was found to be robust to cracking or deformation. Conclusions: DDOFP was customized for pancreatic PDT with superior thermomechanical property and uniform light illumination at both the front-spherical and side-cylindrical areas. This is the smallest clinically available optical fiber per our knowledge and officially approved by the Korea Food and Drug Administration (item approval number: 17-516). DDOFP can contribute immensely toward the efficient delivery of pancreatic PDT and photothermal therapy.

Evaluation of Biological Activity of Different Wavelengths of Low-Level Laser Therapy on the Cancer Prostate Cell Line Compared With Cisplatin

Introduction: Cancer is one of the most important problems in the world. Low-level laser therapy (LLLT) has been emerged as a new approach, having both stimulation and inhibition effects on cellular function. The goal of this study was to analyze and compare the different concentrations of cisplatin and wavelengths of laser therapy on the LnCap cell lines. Methods: LnCap cells were cultured and treated with different concentrations of cisplatin (0.1, 0.4, 0.8, 1.2 and 2 µg/mL for 24 hours) and wavelengths of laser therapy (610, 630 and 810 nm) (0.45 J/cm²) separately. The viability of cells was examined by MTT assay and IC50 was also calculated. Furthermore, a combination of cisplatin IC50 (24 hours) and different wavelengths of the laser was examined. Results: The results of this study showed that 2 µg/mL of cisplatin has the most significant reduction effect on the cell viability of the LnCap cell line. Cisplatin decreased the viability of cells in a dose-dependent manner. Moreover, IC50 of cisplatin was 1.24 µg/mL. On the other hand, LLLT with wavelengths of 610, 630 and 810 nm did not show notable biological effects on cell viability. Conclusion: As known, cisplatin has the capability to reduce the viability of LnCap cell lines. However, LLLT cannot be a remarkable option for the treatment of prostate cancer. Therefore, although laser therapy showed praiseful therapeutic activity against some cancer cell lines, in this study the results indicated that defined laser wavelengths had no inhibitory effects against the prostate cancer cell line.

Bleomycin administered by laser-assisted drug delivery or intradermal needle-injection results in distinct biodistribution patterns in skin: in vivo investigations with mass spectrometry imaging

Bleomycin (BLM) is being repositioned in dermato-oncology for intralesional and intra-tumoural use. Although conventionally administered by local needle injections (NIs), ablative fractional lasers (AFLs) can facilitate topical BLM delivery. Adding local electroporation (EP) can augment intracellular uptake in the target tissue. Here, we characterize and compare BLM biodistribution patterns, cutaneous pharmacokinetic profiles, and tolerability in an in vivo pig model following fractional laser-assisted topical drug delivery and intradermal NI, with and without subsequent EP. In vivo pig skin was treated with AFL and topical BLM or NI with BLM, alone or with additional EP, and followed for 1, 2 and 4 h and eventually up to 9 d. BLM biodistribution was assessed by spatiotemporal mass spectrometry imaging. Cutaneous pharmacokinetics were assessed by mass spectrometry quantification and temporal imaging. Tolerability was evaluated by local skin reactions (LSRs) and skin integrity measurements. AFL and NI resulted in distinct BLM biodistributions: AFL resulted in a horizontal belt-shaped BLM distribution along the skin surface, and NI resulted in BLM radiating from the injection site. Cutaneous pharmacokinetic analyses and temporal imaging showed a substantial reduction in BLM concentration within the first few hours following administration. LSRs were tolerable overall, and all interventions permitted almost complete recovery of skin integrity within 9 d. In conclusion, AFL and NI result in distinct cutaneous biodistribution patterns and pharmacokinetic profiles for BLM applied to in vivo skin. Evaluation of LSRs showed that both methods were similarly tolerable, and each method has potential for individualized approaches in a clinical setting.

Ultrasound-Guided Laser Ablation After Excisional Vacuum-Assisted Breast Biopsy for Small Malignant Breast Lesions: Preliminary Results

Background:

The purpose of this preliminary study is to evaluate the feasibility of the excisional ultrasound (US) guided vacuum-assisted breast biopsy (VAE), followed by US-guided Laser Interstitial Thermal Therapy (LITT) in the treatment of unifocal ductal breast carcinomas ≤ 1 cm and estimate the ablation rate analyzing the final histopathological results after subsequent surgical excision.

Methods:

In a single session 11 female patients with unifocal less than a centimeter breast cancer underwent 2 different minimally invasive percutaneous US-guided techniques: a VAE breast biopsy with an 8 G needle to remove the lesion and, immediately after, a LITT ablation in the biopsy site. Four weeks later, all patients underwent radiological follow-up. Afterward, a systematic surgery was performed, the ablation rate was calculated, and iconographic and histological features were correlated.

Results:

Average maximum diameter of the lesions was 7.6 mm (5-10 mm). No patient reported pain or discomfort during procedure. 1/11 patient (9.1%) reported an early minor complication (a small superficial skin burn). After surgical excision, the histopathological evaluation reported in 10/11 cases (90.9%) complete ablation of the target lesion. In only one case (9.1%) residual cancer was detected. The necrotic-hemorrhagic cavities showed a mean maximum diameter of 27.3 mm (20-35 mm).

Conclusions:

Laser ablation performed after excisional biopsy could be considered a valid alternative to surgical excision for the treatment of lesions ≤ 1 cm, if carried out by expert radiologists. The association of these minimally invasive percutaneous methods has proven to be reliable, fast, and safe with an ablation rate of 90.9% and excellent aesthetic results. RM and CESM are potentially able to quantifying treatment results and to follow-up the ablation effects.

Assessing the Outcomes of Focused Heating of the Skin by a Long-Pulsed 1064 nm Laser with an Integrated Scanner, Infrared Thermal Guidance, and Optical Coherence Tomography

BACKGROUND AND OBJECTIVE: Long-term benefits can be predicted by the incorporation of more intelligent systems in lasers and other devices. Such systems can produce more reliable zones of thermal injury when used in association with non-invasive monitoring and precise laser energy delivery. The more classical endpoint of tumor destruction with radiofrequency or long-pulsed (LP) 1064 nm laser is the non-specific appearance of tissue graying and tissue contraction. Herein we discuss combining non-invasive LP 1064 nm Nd:YAG treatment with the assistance of optical coherence tomography (OCT) and the forward-looking infrared (FLIR) thermal camera while testing literature-based formulae for thermal destruction.

STUDY DESIGN/MATERIALS AND METHODS

The skin on the forearm and back of two consenting volunteers was marked and anesthetized with lidocaine with epinephrine. The parameters of a scanner-equipped LP 1064 nm Nd:YAG laser were adjusted to achieve an epidermal/superficial dermal heating of between 50°C and 60°C over a specified time course. Experimental single treatments examined various adjusted parameters including, fluence, pulse overlap, pulse duration, scan size, and pulse rate. A FLIR camera was used to record skin temperature. Outcome measures included skin temperature, post-treatment appearance, and OCT assessment of skin and vascular damage. The clinical response of each treatment was followed daily for 4 weeks.

RESULTS

Optimal protocols initially raised the skin temperature to between 55°C and 60°C, which was carefully maintained using subsequent laser passes over a 60-second time course. Immediately post laser, clinical responses included erythema, edema, and blistering. Immediate OCT revealed increased vascularity with intact, dilated blood vessels. Prolonged exposure above 60°C resulted in sub-epidermal blistering and an absence of blood flow in the treatment area with prolonged healing.

CONCLUSION

The LP 1064 nm laser can be used to achieve heat-related tissue injury, though the narrow parameters necessary for the desired endpoint require the assistance of IR thermal regulation to avoid unacceptable outcomes. The use of the laser scanner ensures precise energy delivery over a defined treatment area. Future studies might explore this as a selective hyperthermic method for the treatment of non-melanoma skin cancer. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Laser Treatment for Non-Melanoma Skin Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Surgery is the mainstay of treatment for non-melanoma skin cancer. Lasers are an additional option.

OBJECTIVE

The objective of this study was to review the literature on the efficacy and safety of lasers for the treatment of non-melanoma skin cancer.

METHODS

A systematic review and meta-analysis of laser treatment for non-melanoma skin cancer was performed. The primary outcome was recurrence rate (RR).

RESULTS

The review included 32 studies (six randomized controlled trials and 26 cohort studies): 27 evaluated basal cell carcinomas (BCCs), three squamous cell carcinomas, and two both, for a total of 4755 BCCs and 214 squamous cell carcinoas. Most BCCs were low risk. The Nd:YAG laser (seven studies, 3286 BCCs) had a 3.1% RR (95% confidence interval [CI] 1.4-6.4%) during a mean follow-up of 7.9 years, with a low rate (< 20%) of scarring and dyspigmentation. The CO₂ laser (ten studies, 904 BCCs) had a 9.4% RR (95% CI 4.1-20) during a mean follow-up of 2.1 years, with a low rate of side effects. The pulsed dye laser (eight studies, 206 BCCs) had a 38% RR (95% CI 24-55). In two studies, the Nd:YAG laser demonstrated a RR of 10% (95% CI 2-31) for Bowen's disease, and in three studies, the CO₂ laser demonstrated a RR of 22% (95% CI 5-61) for squamous cell carcinoma.

CONCLUSIONS

Based on cohort studies, the Nd:YAG laser is a safe and efficacious modality for the treatment of low-risk BCC. Based on settings applied in prior studies in the literature, the CO₂ laser is less efficacious than the Nd:YAG laser, thus it cannot be recommended for BCC treatment. Insufficient data preclude conclusions regarding laser treatment for squamous cell carcinoma.

REGISTRATION

PROSPERO registration number CRD42019129717.

Topical photodynamic therapy combined with ablative "light needles" against basal cell carcinoma

Basal cell carcinoma (BCC), a non-melanoma cancer with high morbidity in the elders, is a type of limited skin cancer with a projected appearance. Traditional treatments such as oral or injection administration are likely to result in serious side effects. Here, we developed a strategy that combined photodynamic therapy (PDT) with ablative light "needles" (carbon-dioxide laser) for the treatment of BCC, involving β-Tetra-(4-carboxyl-phenoxy)-zinc phthalocyanine (ZnPC₄) cubic phases with high drug loading, easy preparation, long local retention, good spreading ability and little toxicity. A model of nude mice with BCC was established for the study of pharmacodynamics. The light needles of low energy (53 mJ/cm²) used here could promote transdermal absorption of ZnPC₄ cubic phases while those of high energy (238 mJ/cm²) alone could completely kill tumor cells with no recurrence. However, ZnPC₄ cubic phases alone could not completely inhibit tumor growth, for it was distributed mainly at the topical administration site in the absence of any adjuvant technology. Therefore, the combination of photodynamics and light needles offered a good solution. Especially, the combined use of light needles with high energy and ZnPC₄ cubic phases can treat BCC efficiently with no recurrence. This approach is expected to be a novel and promising medication against BCC.

A Vismodegib Experience in Elderly Patients with Basal Cell Carcinoma: Case Reports and Review of the Literature

Cutaneous basal cell carcinoma (BCC) is the most common type of human tumor, and its incidence rate is increasing worldwide. Up until a few years ago, therapeutic options have been limited for patients with advanced BCC (including metastatic and locally-advanced BCC). Over the last few years, promising systemic therapies have been investigated for the treatment of advanced BCC. In particular, the Hedgehog signaling inhibition has shown remarkable results for this population. Hedgehog inhibitors, represented by vismodegib and sonidegib, have been approved by the Food and Drug Administration and the European Medicines Agency for the treatment of both locally advanced and metastatic BCC, with, generally, a good safety profile. Notwithstanding the late onset of BCC in the global population, associated with life expectancy increase, only a few clinical trials have evaluated the efficacy and safety profile of Hedgehog inhibitors in this complex and neglected population. Herein, we review the major mechanisms implicated in the pathogenesis of BCC focusing on the Hedgehog signaling pathway and its therapeutic role in the elderly population. Finally, we report two case reports of BCC elderly patients in order to demonstrate both efficacy and safety of the Hedgehog inhibitors.

In situ vaccination with laser interstitial thermal therapy augments immunotherapy in malignant gliomas

INTRODUCTION

Laser interstitial thermal therapy (LITT) remains a promising advance in the treatment of primary central nervous system malignancies. As indications for its use continue to expand, there has been growing interest in its ability to induce prolonged blood brain barrier (BBB) permeability through hyperthermia, potentially increasing the effectiveness of current therapeutics including BBB-impermeant agents and immunotherapy platforms.

METHODS

In this review, we highlight the mechanism of hyperthermic BBB disruption and LITT-induced immunogenic cell death in preclinical models and humans. Additionally, we summarize ongoing clinical trials evaluating a combination approach of LITT and immunotherapy, which will likely serve as the basis for future neuro-oncologic treatment paradigms.

RESULTS

There is evidence to suggest a highly immunogenic response to laser interstitial thermal therapy through activation of both the innate and adaptive immune response. These mechanisms have been shown to potentiate standard methods of oncologic care. There are only a limited number of clinical trials are ongoing to evaluate the utility of LITT in combination with immunotherapy.

CONCLUSION

LITT continues to be studied as a possible technique to bridge the gap between exciting preclinical results and the limited successes seen in the field of neuro-oncology. Preliminary data suggests a substantial benefit for use of LITT as a combination therapy in several clinical trials. Further investigation is required to determine whether or not this treatment paradigm can translate into long-term durable results for primary intracranial malignancies.

Treatment of benign eyelid lesions with Nd:YVO laser: a prospective study

The purpose of this prospective cohort study, including consecutively selected patients, was to evaluate the outcomes of Nd:YVO laser-assisted photocoagulation for the removal of benign eyelid lesions. An emulsion of lidocaine and prilocaine was used for dermal analgesia and subcutaneous injection of 2% lidocaine was performed as needed. Follow-up included two visits, at day 15 and 45 postoperatively, in order to assess time of wound healing, postoperative complications, need for additional treatment, and patient's satisfaction. A total of 101 lesions of 66 patients were included, with a mean age of 55.4 ± 15.3 years. All patients were Caucasian and 62% were female. Papilloma was the most common lesion identified (61%). No major complications were reported during and after the procedure. Complete epithelization occurred in 82% and 100%, at the 15 and 45-day visit, respectively. All patients were satisfied with the cosmetic result. Only one patient was proposed for additional therapy during the follow-up period. In conclusion, this study supports Nd:YVO laser-assisted treatment as an effective and safe alternative to conventional surgery for the removal of benign eyelid lesions. The technique is well accepted, easy to perform, and provides excellent cosmetic and functional results.

Reflectance confocal microscopy-guided carbon dioxide laser ablation of low-risk basal cell carcinomas: A prospective study

BACKGROUND

Basal cell carcinoma (BCC) treatment modalities can be stratified by tumor subtype and recurrence risk. The main limitation of nonsurgical treatment modalities is the lack of histopathologic confirmation. Reflectance confocal microscopy (RCM) is a noninvasive imaging device that provides quasihistologic images.

OBJECTIVE

To evaluate the feasibility and efficacy of RCM-guided carbon dioxide (CO₂) laser ablation of low-risk BCCs.

METHODS

Prospective study with biopsy specimen-proven low-risk BCCs imaged with RCM. RCM was performed on these sites before and after ablation. If residual tumor was found, a new series of laser passes were performed. The patients were then monitored for recurrence clinically and with RCM.

RESULTS

Twenty-two tumor sites in 9 patients (5 men, 4 women) were imaged and treated. Median age was 59 ± 12.9 years (range, 30-74 years). Mean tumor size was 7.7 mm (range, 5-10 mm). Residual tumor was identified in 5 of 22 cases (22.7%) under RCM on immediate first-pass postablation sites, prompting additional laser passes. Median follow-up was 28.5 months (range, 22-32 months) with no recurrences found.

CONCLUSIONS

Addition of RCM to laser ablation workflow can detect subclinical persistent tumor after initial ablation and may serve as an aid to increase the efficacy of laser ablation.

Updates on the Management of Non-Melanoma Skin Cancer (NMSC)

Non-melanoma skin cancers (NMSCs) are the most common malignancy worldwide, of which 99% are basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of skin. NMSCs are generally considered a curable diseases, yet they currently pose an increasing global healthcare problem due to rising incidence. This has led to a shift in emphasis on prevention of NMSCs with development of various skin cancer prevention programs worldwide. This article aims to summarize the most recent changes and advances made in NMSC management with a focus on prevention, screening, diagnosis, and staging.