Immunocryosurgery for basal cell carcinoma: results of a pilot, prospective, open-label study of cryosurgery during continued imiquimod application

BCC and Immunocryosurgery scar differentiation through computational resolution-enhanced OCT images and skin optical attenuation: A proof-of-concept study

Monitoring medical therapy remains a challenging task across all non-surgical skin cancer treatment modalities. In addition, confirmation of residual tumours after treatment is essential for the early detection of potential relapses. Optical coherence tomography (OCT), a non-invasive method for real-time cross-sectional imaging of living tissue, is a promising imaging approach for assessing relatively flat, near-surface skin lesions, such as those that occur in most basal cell carcinomas (BCCs), at the time of diagnosis. However, the skin's inherent property of strong light scattering impedes the implementation of OCT in these cases due to the poor image quality. Furthermore, translating OCT's optical parameters into practical use in routine clinical settings is complicated due to substantial observer subjectivity. In this retrospective pilot study, we developed a workflow based on the upscale of the OCT images resolution using a deep generative adversarial network and the estimation of the skin optical attenuation coefficient. At the site of immunocryosurgery-treated BCC, the proposed methodology can extract optical parameters and discriminate objectively between tumour foci and scar tissue.

Thermal Ablation in the Liver: Heat versus Cold-What Is the Role of Cryoablation?

Cryoablation is commonly used in the kidney, lung, breast, and soft tissue, but is an uncommon choice in the liver where radiofrequency ablation (RFA) and microwave ablation (MWA) predominate. This is in part for historical reasons due to serious complications that occurred with open hepatic cryoablation using early technology. More current technology combined with image-guided percutaneous approaches has ameliorated these issues and allowed cryoablation to become a safe and effective thermal ablation modality for treating liver tumors. Cryoablation has several advantages over RFA and MWA including the ability to visualize the ice ball, minimal procedural pain, and strong immunomodulatory effects. This article will review the current literature on cryoablation of primary and secondary liver tumors, with a focus on efficacy, safety, and immunogenic potential. Clinical scenarios when it may be more beneficial to use cryoablation over heat-based ablation in the liver, as well as directions for future research, will also be discussed.

A Fiber Optic Sensor for Monitoring the Spectral Alterations and Depth in Ex Vivo and In Vivo Cryosurgery

This article discusses how to monitor the freezing depth during cryotherapy using a fiber optic array sensor. The sensor was used to measure the backscattered and transmitted light from frozen and unfrozen ex vivo porcine tissue and in vivo human skin tissue (finger). The technique exploited the variations in optical diffusion properties of the frozen and unfrozen tissues to determine the extent of freezing. Ex vivo and in vivo measurements yielded comparable results, despite spectral variations attributable to the hemoglobin absorption peak in the human frozen and unfrozen tissues. However, because the spectral fingerprints of the freeze-thaw process in the ex vivo and in vivo experiments were similar, we could extrapolate the maximum depth of freezing. Therefore, this sensor has the potential to be utilized for monitoring cryosurgery in real time.

The Feasibility of Immunocryosurgery in the Treatment of Non-Superficial, Facial Basal Cell Carcinoma That Relapsed after Standard Surgical Excision: An Experience Report from Two Centers

In this retrospective, chart review study, we evaluated the feasibility of immunocryosurgery in facial, non-superficial basal cell carcinomas (BCC) that had relapsed after standard surgery. Inclusion criteria were (a) 'biopsy confirmed relapse of facial BCC', (b) known 'calendar year of surgical excision(s)', and (c) 'relapse within 10 years after the last surgical excision'. Tumors treated from 1 January 2011 to 31 December 2020 with a standard 5-week immunocryosurgery cycle (daily imiquimod application for 5 weeks and a cryosurgery session at day 14) were included. Descriptive statistics, Kaplan-Meier method, and Cox proportional hazards model were calculated with significance at p < 0.05. From the n = 27 BCC evaluated, n = 20 (74.1 ± 8.4%) cleared after one immunocryosurgery cycle. Two of the remaining cases cleared completely after a repeat cycle, one patient favored surgery, and four BCC did not clear despite additional immunocryosurgery cycles (feasibility 81.5 ± 7.5%). Of the 22 tumors with clinical outcome 'complete clearance with immunocryosurgery', three BCC relapsed at 9, 28, and 50 months. Overall, the 5-year treatment efficacy rate was 60.2 ± 13.4% (mean follow-up 94.6 ± 15.1 months). In total, 20/27 BCC relapses after surgery (74.1%) were tumor-free at the end of personalized follow-up times (66.7 ± 12.4% tumor free patients at 5-year follow-up). Number of tumor relapses before immunocryosurgery was the single predictor of tumor progression after immunocryosurgery (p = 0.012). Conclusively, immunocryosurgery could be further evaluated as an alternative, definitive treatment of selected facial BCC relapsing after surgery.

Clinical application status and prospect of the combined anti-tumor strategy of ablation and immunotherapy

Image-guided tumor ablation eliminates tumor cells by physical or chemical stimulation, which shows less invasive and more precise in local tumor treatment. Tumor ablation provides a treatment option for medically inoperable patients. Currently, clinical ablation techniques are widely used in clinical practice, including cryoablation, radiofrequency ablation (RFA), and microwave ablation (MWA). Previous clinical studies indicated that ablation treatment activated immune responses besides killing tumor cells directly, such as short-term anti-tumor response, immunosuppression reduction, specific and non-specific immune enhancement, and the reduction or disappearance of distant tumor foci. However, tumor ablation transiently induced immune response. The combination of ablation and immunotherapy is expected to achieve better therapeutic results in clinical application. In this paper, we provided a summary of the principle, clinical application status, and immune effects of tumor ablation technologies for tumor treatment. Moreover, we discussed the clinical application of different combination of ablation techniques with immunotherapy and proposed possible solutions for the challenges encountered by combined therapy. It is hoped to provide a new idea and reference for the clinical application of combinate treatment of tumor ablation and immunotherapy.

Laser Immunotherapy: A Potential Treatment Modality for Keratinocyte Carcinoma

Simple Summary

In light of expanding incidences of keratinocyte carcinoma (KC) with many patients developing multiple tumors, the demand for new treatment modalities is high. With the approval of cemplimab for locally advanced and metastasizing basal cell carcinoma and squamous cell carcinoma, KC is now included as an indication for systemic immunotherapy. At present, however, systemic KC therapy remains limited by the severe side effects associated with treatment. Immunotherapy might be more broadly applied if locally administered. Localized to the skin, KCs are easily accessible to topical drugs and physical interventions such as laser. There is an increasing appreciation of lasers’ potential to activate an immune response. Further enhancement of the laser-based immune activation might be obtained by combining laser and immunotherapeutic agents, known as laser immunotherapy. In search of new treatment modalities for KC and aiming to broaden the field of KC immunotherapy, this review discusses the current literature on immune activation following both laser monotherapy and laser immunotherapy.

Abstract

The role of the immune system in cancer growth is well recognized and the development of immunotherapy represents a breakthrough in cancer treatment. Recently, the use of systemic immunotherapy was extended to keratinocyte carcinoma (KC), specifically locally advanced and metastasizing basal and squamous cell carcinoma. However, since most KC lesions are non-aggressive, systemic treatment with associated side effects is rarely justified. Conversely, topical immunotherapy with imiquimod remains restricted to premalignant and superficial lesions. Use of laser in the treatment of KC has evolved from physical tumor destruction and laser-assisted drug delivery to laser-mediated immune modulation. Evidence indicates that laser monotherapy can lead to immune cell infiltration, tumor reduction and resistance to tumor re-inoculation. Combining laser with immunotherapeutic agents, termed laser immunotherapy (LIT), may further potentiate immune activation and tumor response. Studies on LIT show not only direct anti-tumor effects but systemic adaptive immunity, illustrated by the prevention of tumor recurrence and regression in distant untreated tumors. These findings imply a therapeutic potential for both local and metastatic disease. This work provides rationales for immune-based treatment of KC and presents the current status of KC immunotherapy. Aiming to expand the field of KC immunotherapy, the review discusses the literature on immune activation following laser monotherapy and LIT.

A Review of Immunocryosurgery and a Practical Guide to Its Applications

Immunocryosurgery is a minimally invasive combinational therapeutic procedure that has been designed, developed, and evaluated in the Dermatology Department of the University of Ioannina from 2004. In a fixed time protocol, this approach combines immune stimulatory therapy with imiquimod and cryosurgery, i.e., cryosurgery is applied during continuous imiquimod treatment. Laboratory findings in tissue and blood level credit the efficacy to the synergy of imiquimod and cryosurgery. The synergy has been established through clinical trials and the excellent feasibility and efficacy demonstrated in clinical practice. Immunocryosurgery has extensive proof of excellent efficacy, comparable to surgery, in the treatment of basal cell carcinoma. It has also been evaluated in cases of Bowen's disease, keratoacanthoma, Merkel cell carcinoma, lentigo maligna, and cutaneous squamous cell carcinoma with or without the addition of adjuvants. The aims of this review are to detail the immunocryosurgery protocol with the addition of daily practice clinical tips, compile data on the mechanism of action of immunocryosurgery, and delineate indications and possible future applications. Most of the available data originate from the treatment of BCC, of all histological types and localizations, and the principles reported mainly reflect on evidence related to the treatment of this common skin cancer.

Rate of Freeze Impacts the Survival and Immune Responses Post Cryoablation of Melanoma

The emergence of ablative therapies has revolutionized the treatment of inoperable solid tumors. Cryoablation stands out for its uniqueness of operation based on hypothermia, and for its ability to unleash the native tumor antigens, resulting in the generation of anti-tumor immune responses. It is not clearly understood how alterations in the rate of freeze impact the immune response outcomes. In this study, we tested fast freeze and slow freeze rates for their locoregional effectiveness and their ability to elicit immune responses in a B16F10 mouse model of melanoma. Tumor bearing mice treated with fast freeze protocol survived better than the ones treated with slow freeze protocol. Fast freeze resulted in a higher magnitude of CD4+ and CD8+ T-cell responses, and a significantly extended survival post re-challenge. Thus, fast freeze rate should be applied in any future studies employing cryoablation as an in vivo vaccination tool in conjunction with targeted immunotherapies.

Cryoablation and Immunotherapy: An Enthralling Synergy to Confront the Tumors

Treatment of solid tumors by ablation techniques has gained momentum in the recent years due to their technical simplicity and reduced morbidity as juxtaposed to surgery. Cryoablation is one of such techniques, known for its uniqueness to destroy the tumors by freezing to lethal temperatures. Freezing the tumor locally and allowing it to remain in situ unleashes an array of tumor antigens to be exposed to the immune system, paving the way for the generation of anti-tumor immune responses. However, the immune responses triggered in most cases are insufficient to eradicate the tumors with systemic spread. Therefore, combination of cryoablation and immunotherapy is a new treatment strategy currently being evaluated for its efficacy, notably in patients with metastatic disease. This article examines the mechanistic fabric of cryoablation for the generation of an effective immune response against the tumors, and various possibilities of its combination with different immunotherapies that are capable of inducing exceptional therapeutic responses. The combinatorial treatment avenues discussed in this article if explored in sufficient profundity, could reach the pinnacle of future cancer medicine.

Alterations in the inflammatory cells infiltrating basal cell carcinomas during immunocryosurgery

Immunocryosurgery, the combination modality of a cryosurgery session at day 14 of a 5-week daily imiquimod treatment cycle, has shown remarkable efficacy in the treatment of basal cell carcinoma (BCC). The modality was designed to exploit synergy of antitumor effects, including the induction of immune responses, elicited by imiquimod and cryosurgery. Herein, we report on the infiltration of the BCC by selected inflammatory cell species during an immunocryosurgery treatment cycle. The density of tissue infiltrating CD68⁺, CD3⁺ and Foxp3⁺ cells was studied by immunohistochemistry in 56 BCC biopsies from 28 treated sites (26 patients) at baseline and at days 12, 16 or 28 during treatment. Immunocryosurgery induces statistically significant alterations in all three cell species (p < 0.003): The density of CD68⁺ increased already by day 12 and remained at a higher level during the treatment thereafter. The density of CD3⁺ cells increased significantly between days 12 and 16 of treatment. The density of T_reg (Foxp3⁺) cells increased in the early phase of treatment (highest at day 12) to decrease significantly already 2 days after the cryosurgery session (day 16) and thereafter up to day 28 of the treatment cycle (p = 0.033). Within the tumor tissue, these alterations result in an abrupt increase in the CD3⁺/Foxp3⁺ ratio, a finding suggesting that the cryosurgical perturbation may probably play a decisive modulating role in the cellular composition of the inflammatory infiltrate during immunocryosurgery, eventually heralding the induction of an effective tumor-destructing immune response.

Immunocryosurgery - an effective combinational modality for Bowen's disease

Bowen's disease (BD) is widely treated with topical imiquimod or cryosurgery. The present single-center retrospective study reports on the application of standardized immunocryosurgery (cryosurgery during ongoing topical imiquimod) for the treatment of BD. Daily imiquimod 5% cream was applied on BD lesion and a 5 mm rim around it in 5-week treatment cycles; cryosurgery (liquid N₂ , open spray; 2 cycles, 15 second each) was performed at the end of the second week of each treatment cycle. Between 1/1/2009 and 31/12/2014 21 patients (mean age ± SD: 74.4 ± 8.0 years; 12 males) with 24 lesions (mean maximum diameter ± SD: 45.8 ± 50.9 mm; range: 9-200 mm) completed the protocol. The anatomic distribution of the lesions included face/scalp (Ν = 14), neck/trunk (Ν = 6), and extremities (Ν = 4). Twenty-one out of twenty-four lesions with diameter <80 mm cleared after one immunocryosurgery cycle, while the rest three tumors (with the largest diameters: 100, 180, 200 mm) required two treatment cycles for complete response (clearance rate: 100%). After a median follow-up of 24 months (range: 6-60 months) the overall effectiveness was 91.7%: 22/24 lesions remained in sustained complete remission. With the exception of a variable degree of hypopigmentation, the cosmetic outcome was satisfactory even for extensive lesions. Immunocryosurgery, is feasible and highly efficacious minimally-invasive treatment alternative for BD.

Mechanisms of cryoablation: clinical consequences on malignant tumors

While the destructive actions of a cryoablative freeze cycle are long recognized, more recent evidence has revealed a complex set of molecular responses that provides a path for optimization. The importance of optimization relates to the observation that the cryosurgical treatment of tumors yields success only equivalent to alternative therapies. This is also true of all existing therapies of cancer, which while applied with curative intent; provide only disease suppression for periods ranging from months to years. Recent research has led to an important new understanding of the nature of cancer, which has implications for primary therapies, including cryosurgical treatment. We now recognize that a cancer is a highly organized tissue dependent on other supporting cells for its establishment, growth and invasion. Further, cancer stem cells are now recognized as an origin of disease and prove resistant to many treatment modalities. Growth is dependent on endothelial cells essential to blood vessel formation, fibroblasts production of growth factors, and protective functions of cells of the immune system. This review discusses the biology of cancer, which has profound implications for the diverse therapies of the disease, including cryosurgery. We also describe the cryosurgical treatment of diverse cancers, citing results, types of adjunctive therapy intended to improve clinical outcomes, and comment briefly on other energy-based ablative therapies. With an expanded view of tumor complexity we identify those elements key to effective cryoablation and strategies designed to optimize cancer cell mortality with a consideration of the now recognized hallmarks of cancer.

The application of Levulan-based photodynamic therapy with imiquimod in the treatment of recurrent basal cell carcinoma

BACKGROUND

Common skin tumors like basal- and squamous-cell carcinoma present a serious problem in modern medicine. Exposure to ultraviolet solar radiation is the main cause of these lesions. Since application of Aldara and PDT separately is well documented, we decided to use both methods together. The aim of our study was to evaluate the effectiveness of local photodynamic therapy supplemented with topical application of Aldara in basal-cell carcinoma.

MATERIAL/METHODS

Thirty-four patients ages 50 to 68 years were enrolled to the trial and underwent PDT treatment. Each case of BCC was histopathologically confirmed. Ten patients were subjected to local Levulan-PDT and placebo (Eucerin as vehicle cream), and 24 patients were subjected to Levulan-PDT and imiquimod. Photodynamic diagnosis (PDD) was used to detect and visualize suspicious foci (including cancer lesions).

RESULTS

In the group of patients who were treated using Levulan-PDT and placebo, 6 patients (60%) were totally cured and 4 lesions (40%) significantly decreased in size. In the group of patients treated with Levulan-PDT and imiquimod, 18 lesions totally disappeared (75%), 6 lesions significantly diminished, and in 1 patient small foci of previously excised BCC developed again in scar tissue 10 month after the first control examination.

CONCLUSIONS

Cure was achieved without any scarring and with very good cosmetic effects. Although this is the preliminary report, the presented modification of PDT seems to be reasonable and promising in treating basal-cell carcinoma.

Potential efficacy of imiquimod on immunity-related cytokines in murine skin in vivo and in human Langerhans cells in vitro

INTRODUCTION

Imiquimod, an immune-response modifier, has been proven to be clinically effective in the treatment of viral infections and skin cancers, but its mechanism of action remains poorly understood. This study aimed to assess the effects of imiquimod on the expression of three immunity-related cytokines, TNF-α, IL-1β, and IL-6.

MATERIALS AND METHODS

Female BALB/C mice were treated for seven days with topical 1% imiquimod cream; they were then killed and skin samples were snap-frozen. In the in vitro studies, both purified LCs and HaCaT cells were incubated with 5 μg/ml imiquimod for four hours. In all samples, the mRNA levels of TNF-α, IL-1β, and IL-6 were then detected by reverse transcription polymerase chain reaction, and the secretion levels were determined by an enzyme-linked immunosorbent assay.

RESULTS

Imiquimod upregulated the mRNA and protein expression levels of TNF-α, IL-1β, and IL-6 in the skin of imiquimod-treated BALB/C mice and in human LCs, compared with untreated controls (P<0.05). However, there was no significant difference in the expression of these cytokines in imiquimod-treated and untreated HaCaT cells.

CONCLUSIONS

These findings indicate that imiquimod increased the expression of TNF-α, IL-1β, and IL-6 in skin and that the target cell of imiquimod may be the LCs but is unlikely to be the epidermal keratinocytes.