The potential utility of integrated reflectance confocal microscopy-optical coherence tomography for guiding triage and therapy of basal cell carcinomas

One-Stop Shop: Diagnosis and Treatment of Basal Cell Carcinoma in One Step

Monitoring the tumor margins of basal cell carcinomas is still a challenge in everyday clinical practice. Usually, the clinical margins of the tumor are marked by the naked eye or, even better, with dermoscopy before surgery and then examined in detail after the operation using histological examination. In order to achieve tumor freedom, several surgical steps are sometimes necessary, meaning that patients spend longer periods in hospital and the healthcare system is burdened more as a result. One way to improve this is the one-stop shop method, which requires precise diagnostics and margin marking before and during surgery so that tumor freedom can be achieved after just one surgery. For this reason, the current status of the diagnosis and treatment of basal cell carcinomas before and after surgery is to be examined following extensive literature research using devices and methods that have already been tested in order to determine how a simplified process of tumor margin control of basal cell carcinomas can be made possible both in vivo and ex vivo.

Basal Cell Carcinoma After High Dose Rate Brachytherapy: Medium-term Dermoscopic Evaluation of Cancer's Response

INTRODUCTION

Basal cell carcinoma of the facial region remains a challenge for contemporary oncology due to the presence of aesthetic regions and critical organs. Surgery is not always the optimal solution, and high dose rate (HDR) brachytherapy has emerged as an organ-sparing treatment method whose effectiveness has been proven by a growing number of publications. Dermoscopy is a diagnostic tool that bridges clinical and pathological examination of skin lesions. It is routinely used for diagnosis, monitoring of treatment, and post-treatment evaluation; however, the literature lacks data concerning changes in dermoscopic patterns of skin cancers during and after irradiation.

METHODS

Our team conducted a prospective non-randomized trial of 39 patients with high-risk basal cell carcinomas (BCCs), mostly localized within the high-risk zone (H-zone) of the facial region, and who qualified for HDR brachytherapy. HDR contact brachytherapy with custom-made surface molds was introduced, delivering a dose of 45 Gy in 9 fractions prescribed to the tumor. Every patient was observed clinically and dermoscopically at three observational points: before treatment, at the end of treatment (3rd week), and 24 weeks after the end of therapy. The evolution of clinical and dermoscopic patterns was observed by two independent dermoscopists using current diagnostic criteria. A database of 12,088 photographic observations was evaluated.

RESULTS

Univariate logistic regression proved that brachytherapy decreases the number of clinical and dermoscopic patterns typical for basal cell carcinoma, as well as dermoscopic features not related to BCC, presumably due to the formation of scar tissue. In addition, univariate logistic regression with random effects proved a positive correlation between tumor size and presence of various dermoscopic patterns typical for BCC.

CONCLUSION

Dermoscopy is proven to be easy to perform and an adequate monitoring tool for patients with BCCs undergoing HDR brachytherapy.

Skin Cancer Pathobiology at a Glance: A Focus on Imaging Techniques and Their Potential for Improved Diagnosis and Surveillance in Clinical Cohorts

Early diagnosis is essential for completely eradicating skin cancer and maximizing patients' clinical benefits. Emerging optical imaging modalities such as reflectance confocal microscopy (RCM), optical coherence tomography (OCT), magnetic resonance imaging (MRI), near-infrared (NIR) bioimaging, positron emission tomography (PET), and their combinations provide non-invasive imaging data that may help in the early detection of cutaneous tumors and surgical planning. Hence, they seem appropriate for observing dynamic processes such as blood flow, immune cell activation, and tumor energy metabolism, which may be relevant for disease evolution. This review discusses the latest technological and methodological advances in imaging techniques that may be applied for skin cancer detection and monitoring. In the first instance, we will describe the principle and prospective clinical applications of the most commonly used imaging techniques, highlighting the challenges and opportunities of their implementation in the clinical setting. We will also highlight how imaging techniques may complement the molecular and histological approaches in sharpening the non-invasive skin characterization, laying the ground for more personalized approaches in skin cancer patients.

Design and Validation of a Handheld Optical Polarization Imager for Preoperative Delineation of Basal Cell Carcinoma

Simple Summary

Skin cancer is the most common malignancy in humans. The goal of this study was to design, implement, and clinically test a novel handheld optical polarization imaging (OPI) system for rapid and noninvasive detection of basal cell carcinoma (BCC) margins. The device is compact, lightweight, and can be operated with minimal training. To validate the handheld imager, 10 subjects with biopsy-confirmed BCC were imaged prior to Mohs surgery. The optical images were processed using a spectral encoding method to increase the accuracy of the tumor boundary delineation. Preoperative margin assessment results from the OPI were compared to the surgeon’s clinical evaluation and to the gold standard of histopathology. Our findings indicate that OPI may be a valuable tool for optimizing surgical treatment of skin cancer.

Abstract

Background: Accurate removal of basal cell carcinoma (BCC) is challenging due to the subtle contrast between cancerous and normal skin. A method aiding with preoperative delineation of BCC margins would be valuable. The aim of this study was to implement and clinically validate a novel handheld optical polarization imaging (OPI) device for rapid, noninvasive, in vivo assessment of skin cancer margins. Methods: The handheld imager was designed, built, and tested. For clinical validation, 10 subjects with biopsy-confirmed BCC were imaged. Presumable cancer margins were marked by the study surgeon. The optical images were spectrally encoded to mitigate the impact of endogenous skin chromophores. The results of OPI and of the surgeon’s preoperative visual assessment were compared to clinical intraoperative histopathology. Results: As compared to the previous prototype, the handheld imager incorporates automated image processing and has 10-times shorter acquisition times. It is twice as light and provides twice as large a field of view. Clinical validation demonstrated that margin assessments using OPI were more accurate than visual assessment by the surgeon. The images were in good correlation with histology in 9 out of 10 cases. Conclusions: Handheld OPI could improve the outcomes of skin cancer treatments without impairing clinical workflows.

Line-field confocal optical coherence tomography of psoriasis, eczema and lichen planus: a case series with histopathological correlation

BACKGROUND

Line-field confocal optical coherence tomography (LC-OCT) is a novel, non-invasive technique that provides in vivo, high-resolution images in both vertical and horizontal sections.

OBJECTIVES

The aim of the study was to evaluate LC-OCT imaging in some inflammatory disorders and to correlate the resulting features with histopathology.

METHODS

The retrospective study included patients with histopathological confirmed diagnosis of plaque psoriasis, atopic eczema and lichen planus, who were imaged with LC-OCT before the biopsy. LC-OCT was performed with the commercially available LC-OCT device.

RESULTS

A total of 15 adult patients with histopathologically proven plaque psoriasis (N: 5), atopic eczema (N: 5) and lichen planus (N: 5) were included. In all cases, LC-OCT allowed the in vivo recognition of the main microscopic features of the examined inflammatory skin disease, with a strong correlation with histopathology.

CONCLUSIONS

Although future studies on larger series of patients are necessary, LC-OCT, based on these preliminary findings, may represent a promising tool in inflammatory skin disorders with potential applications including enhanced diagnosis, biopsy guidance, follow-up and treatment monitoring.

Fiber‐based hand‐held RCM‐OCT probe for noninvasive assessment of skin lesions and therapy guidance

Noninvasive assessment of skin lesions, especially of basal cell carcinoma (BCC), has benefited more recently from the use of optical imaging techniques such as optical coherence tomography (OCT) and reflectance confocal microscopy (RCM). While RCM provides submicron scale resolution and thus enables identification of skin morphological changes of the skin, with the downside of limited penetration depth, OCT imaging of the same lesion brings the benefit of better resolving its depth of invasion. OCT and RCM can be used either individually or combined within the same instrument for the noninvasive diagnosis of nonmelanoma skin cancers (NMSCs). Their combined use has shown to provide certain benefits such as better characterization of the lesion's margins, both in depth and laterally, as well as improved sensitivity and specificity, as previously demonstrated by our team. In this paper we report a new "fiber-based" implementation of the second-generation RCM-OCT hand-held probe. The fiber-based implementation of both imaging modalities enabled the construction of a smaller footprint/lower weight hand-held probe. Its preliminary evaluation on the skin of healthy volunteers is reported here, demonstrating improved capabilities for resolving sub-cellular structures and image skin morphology with micron-scale resolution to a higher depth than in the previous implementation, while also enabling the construction of angiography maps showing vascular remodeling.

2021 international consensus statement on optical coherence tomography for basal cell carcinoma: image characteristics, terminology and educational needs

BACKGROUND

Despite the widespread use of optical coherence tomography (OCT) for imaging of keratinocyte carcinoma, we lack an expert consensus on the characteristic OCT features of basal cell carcinoma (BCC), an internationally vetted set of OCT terms to describe various BCC subtypes, and an educational needs assessment.

OBJECTIVES

To identify relevant BCC features in OCT images, propose terminology based on inputs from an expert panel and identify content for a BCC-specific curriculum for OCT trainees.

METHODS

Over three rounds, we conducted a Delphi consensus study on BCC features and terminology between March and September 2020. In the first round, experts were asked to propose BCC subtypes discriminable by OCT, provide OCT image features for each proposed BCC subtypes and suggest content for a BCC-specific OCT training curriculum. If agreement on a BCC-OCT feature exceeded 67%, the feature was accepted and included in a final review. In the second round, experts had to re-evaluate features with less than 67% agreement and rank the ten most relevant BCC OCT image features for superficial BCC, nodular BCC and infiltrative and morpheaphorm BCC subtypes. In the final round, experts received the OCT-BCC consensus list for a final review, comments and confirmation.

RESULTS

The Delphi included six key opinion leaders and 22 experts. Consensus was found on terminology for three OCT BCC image features: (i) hyporeflective areas, (ii) hyperreflective areas and (iii) ovoid structures. Further, the participants ranked the ten most relevant image features for nodular, superficial, infiltrative and morpheaform BCC. The target group and the key components for a curriculum for OCT imaging of BCC have been defined.

CONCLUSION

We have established a set of OCT image features for BCC and preferred terminology. A comprehensive curriculum based on the expert suggestions will help implement OCT imaging of BCC in clinical and research settings.

Assessing Light and Energy-Based Therapy by Optical Coherence Tomography and Reflectance Confocal Microscopy: A Randomized Trial of Photoaged Skin

BACKGROUND AND OBJECTIVES

Image-guided quantitative and semi-quantitative assessment of skin can potentially evaluate treatment efficacy. Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) are ideal for this purpose. This study assessed clinically relevant statistical changes in RCM and OCT features in photoaged skin after light and energy-based therapy.

METHODS

Novel statistical analyses were performed using OCT and RCM data collected during a previously published trial: a 12-week study of female décolleté skin randomized to four areas treated with thulium laser (L), photodynamic therapy (PDT), combined L-PDT, and control. Eight semi-quantitative RCM scores of photodamage and OCT measurements of skin roughness, blood flow, and epidermal thickness (ET) were evaluated and compared to dermoscopy and clinical skin scores. In statistical analysis, estimated treatment difference (ETD) was calculated.

RESULTS

Twelve women with moderate to severe photodamage were included. RCM and OCT data demonstrated a trend towards rejuvenation of epidermis with increased ET, changes in skin surface, and improved honeycomb pattern in RCM. In angiographic OCT, non-significant changes towards more regular capillary meshes were shown, which matched a decline in appearance of gross telangiectasias in dermoscopy. Improved skin tone after laser and L-PDT was identified in RCM, showing less edged papillae in 36% and 45%, and lentigo number declined in 55% of patients after treatments in dermoscopy. Based on clinical scores, L-PDT provided the greatest clinical improvement, which corresponded to superior ETD outcomes in ET and edged papillae shown in OCT and RCM, respectively.

CONCLUSION

Objective OCT and RCM assessment of skin rejuvenation was demonstrated in this study. Importantly, image-based improvements corresponded to favorable clinical skin scores and fewer photoaging characteristics in dermoscopy. Importantly, most changes did not reach statistical significance, prompting further studies and emphasizing the modest value of non-randomized, non-blinded anti-aging trials.