Determinação de algoritmo para classificação prognóstica e preditiva de carcinomas de células escamosas cutâneos em cães

Abstract

Squamous cell carcinoma is a malignant epithelial tumor of keratinocytes, composed of heterogeneous cells with varied phenotypes, which occurs mainly in glabrous regions, with little or no pigmentation. The neoplasm is common in dogs, cats, horses and cattle, relatively uncommon in sheep and rare in goats and pigs. In veterinary medicine, the most widely used histological classification is based on the degree of differentiation, differing from human medicine, in which several classification systems are used for oral and cutaneous SCCs, with the multifactorial malignancy classification system, which evaluates morphological characteristics of neoplastic cells. Thus, this study aimed to define morphological elements with potential prognosis through the multifactorial classification system for cutaneous squamous cell carcinomas in dogs. The dissertation consists of two scientific articles, the first of which includes the study of the histopathological classifications of SCCs and the second shows the results of the comparative evaluation of the classification systems of cutaneous SCCs in dogs by histomorphological parameters or by the degree of differentiation. A retrospective study of cutaneous SCC cases in dogs, from 2016 to 2020 diagnosed at the Veterinary Oncology Service of the Federal University of Pelotas (SOVet / UFPel), was carried out. 67 cases were selected from biopsies or necropsies, of these 30 cases were followed up for survival assessment. The histological slides of all cases already diagnosed were reviewed and the lesions graded according to the adapted Nagamine algorithm. The Kappa index (k) was used to compare the methods of classifying cutaneous SCCs in dogs. We also sought to evaluate the utility of the graduation system parameters as prognostic predictors through estimates of sensitivity and specificity and positive predictive value. The analysis of survival data was performed using the Kaplan-Meier method. The survival monitoring of the animals in the study was carried out through quarterly telephone contact with the tutors, for at least 12 months. As for the evaluation of the Kappa index, the value obtained was K = 0.266, indicating that there is little agreement between the diagnostic models. In assessing the usefulness of morphological parameters as prognostic predictors, keratinization and nuclear pleomorphism, score 1, inflammation and invasion pattern, score 2 and mitosis, score 4, showed higher values of sensitivity and PPV. In this study, the average survival time for dogs with cutaneous SCCs was 8.1 months after diagnosis.