Letter

Ex vivo fluorescence confocal microscopy in conjunction with Mohs micrographic surgery for cutaneous squamous cell carcinoma

In order to update recommendations on treatment, supportive care, education, and follow-up of patients with invasive cutaneous squamous cell carcinoma (cSCC), a multidisciplinary panel of experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF), the European Society for Radiotherapy and Oncology (ESTRO), the European Union of Medical Specialists (UEMS), the European Academy of Dermatology and Venereology (EADV), and the European Organisation of Research and Treatment of Cancer (EORTC) was formed. Recommendations were based on an evidence-based literature review, guidelines, and expert consensus. Treatment recommendations are presented for common primary cSCC (low risk, high risk), locally advanced cSCC, regional metastatic cSCC (operable or inoperable), and distant metastatic cSCC. For common primary cSCC, the first-line treatment is surgical excision with postoperative margin assessment or micrographically controlled surgery. Achieving clear surgical margins is the most important treatment consideration for patients with cSCCs amenable to surgery. Regarding adjuvant radiotherapy for patients with high-risk localised cSCC with clear surgical margins, current evidence has not shown significant benefit for those with at least one high-risk factor. Radiotherapy should be considered as the primary treatment for non-surgical candidates/tumours. For cSCC with cytologically or histologically confirmed regional nodal metastasis, lymph node dissection is recommended. For patients with metastatic or locally advanced cSCC who are not candidates for curative surgery or radiotherapy, anti-PD-1 agents are the first-line systemic treatment, with cemiplimab being the first approved systemic agent for advanced cSCC by the Food and Drugs Administration/European Medicines Agency. Second-line systemic treatments for advanced cSCC, include epidermal growth factor receptor inhibitors (cetuximab) combined with chemotherapy or radiotherapy. Multidisciplinary board decisions are mandatory for all patients with advanced cSCC, considering the risks of toxicity, the age and frailty of patients, and co-morbidities, including immunosuppression. Patients should be engaged in informed, shared decision-making on management and be provided with the best supportive care to improve symptom management and quality of life. The frequency of follow-up visits and investigations for subsequent new cSCC depends on underlying risk characteristics.

Characterizing polarization of skin pathologies is still an interested issue for the dermatology community. In a previous study, the present group proposed a Stokes–Muellermatrix polarimetry for differentiating between squamous cell carcinoma tissue and normal healthy tissue in mice. The present study extends our method to the detection of squamous cell carcinoma, basal cell carcinoma and melanoma skin cancer in humans. Using the proposed method, the orientation angle of linear birefringence ($\alpha$), phase retardance ($\beta$), optical rotation angle of circular birefringence ($\gamma$), orientation angle of linear dichroism (${\theta }_{\mathrm{d}}$), linear dichroism (D), circular dichroism (R), degrees of linear depolarization ($e_1$ and $e_2$), degree of circular depolarization ($e_3$), and depolarization index ($\Delta$) are extracted for 72 slices of 12 squamous cell carcinoma samples, 72 slices of 12 basal cell carcinoma samples, 18 slices of 3 melanoma skin cancer samples, and 36 slices of 6 healthy samples. The experimental results show that the cancerous tissue exhibits lower phase retardance ($\beta$) and linear dichroism (D) than healthy skin tissue. Overall, the proposed method provides a useful insight into the characterization optical properties of human skin cancer by Stokes–Mueller matrix polarimetry.

La microscopia confocal ex vivo es un sistema de procesamiento de tejidos que permite el análisis histológico inmediato de tejidos extirpados por medio de láseres diodo con distintos espectros de longitud de onda. En estudios previos la microscopia confocal ex vivo reduce el tiempo de análisis de márgenes de forma muy notable, con una sensibilidad y especificidad respecto a la histopatología del 88% y 99%, respectivamente. Recientemente se ha desarrollado una nueva tecnología que es capaz de proveer imágenes digitales con mayor velocidad y mejor resolución que las obtenidas en los dispositivos previos. Mediante el método de fusión (láseres de fluorescencia y reflectancia que escanean simultáneamente), se reproduce con una tinción digital la hematoxilina y eosina de forma inmediata en cada imagen. La implementación de esta nueva tecnología ha abierto definitivamente una puerta en el diagnóstico inmediato de tejidos.

The ex vivo confocal microscope is an imaging system designed to analyze freshly excised tissue using two diode lasers with different wavelengths. The technique can dramatically reduce margin analysis times and offers a sensitivity of 88% and a specificity of 89% relative to histopathology. A new technology has recently been developed that produces images more quickly and with a higher resolution than before. By means of a fusion mode that combines simultaneously scanned fluorescence and reflectance images, it produces digitally stained images that simulate the effect of hematoxylin-eosin staining. Application of this new technology has opened the door to real-time tissue diagnostics.

Ce « Quoi de neuf en dermatologie instrumentale ? » porte sur la chirurgie cutanée, avec analyse bibliographique de 2015 à 2017.

L’exérèse des cancers cutanés représente une part importante de la dermatologie chirurgicale. Les nouveaux outils d’intelligence artificielle et les progrès des traitements médicaux suffiront-ils pour répondre à la demande croissante de prise en charge avec un nombre de dermatologues en diminution ?

Les erreurs de site d’intervention par mauvais repérage sont dues à de multiples causes. Les photos du site de la tumeur, ± de la biopsie réalisée et un délai < 6 semaines entre biopsie et chirurgie diminuent ce risque, ainsi que le report de l’acte chirurgical.

Les méthodes de visualisation non invasives sont de plus en plus performantes, permettant de mieux repérer les limites tumorales et d’optimiser les chances d’exérèse complète. Elles deviennent très utiles à la chirurgie.

Une mise à jour des Standards, options et recommandations 2005 pour la prise en charge du mélanome M0 a été faite en 2016. La technique « Slow Mohs » est le meilleur traitement du dermatofibrosarcome protubérant (DFSP) dont l’invasion infraclinique asymétrique est fréquente. La pratique de marges chirurgicales larges dans le traitement de formes sévères d’hidradénite suppurée améliore la qualité de vie et diminue le taux de récidives. La chirurgie cutanée est à faible risque de complications postopératoires. Les saignements sont les plus fréquents, favorisés par la prise d’antithrombotiques. Mais il est clairement établi qu’ils ne doivent plus être arrêtés, ni relayés en préopératoire, sauf pour les nouveaux anticoagulants per os qui peuvent être stoppés 24 heures avant le geste et repris quelques heures après. Le risque d’infection du site opératoire (ISO) est rare en dermatologie. Les mesures préventives sont le plus souvent extrapolées à partir d’études d’autres spécialités et le niveau de preuves est faible.

La reconstruction après des pertes de substance (PDS) post exérèse doit être adaptée au cas par cas. Une double transposition est une bonne alternative si un seul lambeauest insuffisant pour la couvrir. La greffe de peau totale (GPT) est minutieuse, mais facile à réaliser. Elle présente peu de risque de complications pour reconstruire les PDS du pavillon de l’oreille dont l’anatomie complexe rend les réparations un peu plus difficiles.

This “What’s new in instrumental dermatology” dedicated skin surgeryis based upon a 2015-2017 literature analysis.

The excision of skin cancers is an important part of surgical dermatology. Will artificial intelligence and new drug be able to face the increasing need for therapy?

Wrong-site surgery is due to multiple factors. Photographs of biopsy site and short time between biopsy and surgery decrease postponement of surgery and wrong-site surgery. Noninvasive imaging technologies are improving and help to delineate skin tumors and increase the probability of complete tumor removal. They are beginning to be an essential tool for skin surgery.

The 2005 recommendations for the management of melanoma stages I to III have been updated in 2016. The Slow-Mohs technique is the better way to treat dermatofibrosarcoma protuberans whose sub-clinical invasion is often asymmetric and unpredictable. Wide local excision for the treatment of severe hidradenitis suppurativa improves the quality of life and decreases recurrence rate.

Cutaneous surgery is considered as safe procedures with a low risk of complications. Postoperative bleedings are the most frequent. Anti-thrombotics enhance the risk, but must not be stopped or bridged, except the novel oral anticoagulants which can be interrupted 24 h before surgery and started again a few hours after. The risk of surgical site infections is low in dermatologic surgery. Most recommended measures to prevent them have been extrapolated from other types of surgery and the level of evidence is low. The reconstruction of skin defect must be adapted on size and location. A birhombic transposition flap is reliable in case of a defect too large to be repaired by a single flap. Full-thickness skin graft is a safe option to repair defect on the external ear.