New Diagnostic Aids for Melanoma

La incidencia de melanoma cutáneo está aumentando progresivamente en Occidente, debido a los hábitos de exposición solar y a una mayor tendencia a consultar lesiones cutáneas. En España se diagnostican al año unos 6.179 casos nuevos al año de melanoma cutáneo. El melanoma es una patología potencialmente curable en los estadios tempranos, lo que obliga a una detección precoz. La mayoría de los melanomas son detectados por el propio paciente. Los sospechados por los médicos de Atención Primaria y dermatólogos suelen presentar estadios más precoces, lo que aumenta la supervivencia. El tratamiento quirúrgico del melanoma es fundamental para el diagnóstico, estadificación y tratamiento adyuvante. A pesar de que la mayoría de los pacientes con melanoma se diagnostican en estadios iniciales, algunos pacientes presentan metástasis a distancia en el momento del diagnóstico y otros desarrollarán metástasis a distancia tras su cirugía inicial. En los últimos años se han realizados múltiples ensayos clínicos que llevaron a la aprobación de fármacos que han cambiado la evolución pronóstica. Los tratamientos de inmunoterapia con inhibidores de PD1 y anti-CTLA4 y la terapia dirigida con inhibidores de BRAF y de MEK han demostrado prolongar la supervivencia global en el melanoma metastásico en comparación con la quimioterapia, lo que ha permitido cambiar el pronóstico en este tipo de pacientes, manteniendo la calidad de vida.

The incidence of cutaneous melanoma is progressive increasing in the West due to sun exposure habits and a greater tendency of consulting for skin lesions. In Spain, approximately 6,179 new cases of cutaneous melanoma are diagnosed per year. Melanoma is a potentially curable pathology in its initial stages, which makes its early detection necessary. The majority of melanomas are detected by the patient. Lesions suspected of being melanoma by primary care physicians and dermatologists tend to be found in earlier stages, which increases survival. Surgical treatment of melanoma is fundamental to diagnosis, staging, and adjuvant treatment. Despite the fact that the majority of patients with melanoma are diagnosed in the initial stages, some patients present with distant metastases at the time of diagnosis and others will develop distant metastases following their initial surgery. In recent years, multiple clinical trials have been conducted which have led to the approval of drugs that have changed the evolution of its prognosis. Immunotherapy treatments with PD-1 and anti-CTLA-4 inhibitors and targeted therapies with BRAF and MEK inhibitors have been shown to prolong overall survival in metastatic melanoma compared to chemotherapy, which has allowed for a change in the prognosis for this type of patient while maintaining quality of life.

Various immune cells are present in the skin and modulate the cutaneous immune response. In order to capture such dynamic phenomena, intravital imaging is an important technique and there is a possibility to provide substantial information that is not available using conventional histological analysis. Multiphoton microscope enable direct, three-dimensional, minimally invasive imaging of biological samples with high spatiotemporal resolution, and now become the main method for intravital imaging studies. Here, we will introduce the latest knowledge obtained by intravital imaging of the skin.

Computer-extracted texture features are relevant to diagnose cutaneous lesions such as melanomas. Our goal is to set a relationship between a well-established descriptive terminology, which describes the attributes of dermoscopic structures based on their aspect rather than their underlying causes, and the computational methods to extract texture-based features. By tackling this problem, we can ascertain what indicators used by dermatologists are reflected in the extracted texture features. We first review the state-of-the-art models for texture extraction in dermoscopic images. By comparing the methods’ performance and goals, we conclude that (I) a single color space does not seem to give performances as good as using several ones, thus the latter is reasonable (II) the optimal number of extracted features seems to vary depending on the method’s goal, and extracting a large number of features can lead to a loss of models robustness (III) methods such as GLCM, Sobel or Law energy filters are mainly used to capture local properties to detect specific dermoscopic structures (IV) methods that extract local and global features, like Gabor wavelets or SPT, tend to be used to analyze the presence of certain patterns of dermoscopic structures, e.g. globular, reticular, etc.

Computerized image analysis methods for dermoscopy are primarily of great interest and benefit, as it provides significant information about the lesion, which can be of pertinence for the clinicians and a stand-alone warning implement. Computer-based diagnostic systems require dedicated image processing algorithms to provide mathematical descriptions of the suspected regions, such systems hold a great potential in oncology. In this paper, we have performed a review of the state of art techniques used in computer-aided diagnostic systems, by giving the domain aspects of melanoma followed by the prominent techniques used in each of the steps. The steps include dermoscopic image pre-processing, segmentation, extraction and selection of peculiar features, and relegation of skin lesions. The paper also presents cognizance to judge the consequentiality of every methodology utilized in the literature, in addition to the corresponding results obtained in this perspective. The inadequacies and the future research directions are accentuated.

Very prevalent in the human population, skin cancers cause numerous deaths annually and the costs associated with their diagnosis and therapy are increasing. The science and technology of nanometer-size materials, nanotechnology, seems the best candidate in the development of alternative approaches for diagnosis, treatment, and prophylaxis of severe diseases, including cancer. Nanotechnology is able to overcome major limitations of current therapeutic strategies by specifically targeting the tumor, by stabilizing chemotherapeutic compounds, and by ensuring a controlled and durable release of the drug. Moreover, due to the special particularities of nanoparticles and complex nanosystems they can be efficiently utilized for skin tumor detection in a fast and secure manner, nanoparticles being able to penetrate and be detected even in the deepest layers of the skin.