Multicentral study for determining the significance of ultrasonic criteria for standardizing the risk of malignancy in superficial lymph nodes

Introduction. The study of lymphatic collectors state in oncological practice is important primarily for identification of prevalence of the pathological process. Various changes in the structure of the lymph nodes (LN) both in benign conditions and in cases of malignant lesions can have similar ultrasound (US) characteristics. The difficulty in interpreting US picture of LN is that there are no clear criteria for differentiation of these conditions. The proposed Russian project of Lymph-NodeRADS.RU classification presents a step-by-step assessment of U S characteristics of the LN by categories with mandatory consideration of the clinical history and the patient’s oncological history.
Aim. To determine the most significant US criteria for a standardized analysis of risks for malignant pathology of the superficial LNs with subsequent distribution into types according to the Lymph-NodeRADS.RU.
Materials and methods. A retrospective analysis of echograms of 246 surface LNs from 3 anatomical zones was performed: 155 head / neck, 56 axillary, 35 inguinal. Of these samples 71 were without and 175 were with malignant lesions. The presence and nature of 209 LN lesions were confirmed by morphological studies (cyto- or histological, including immunohistochemical assessments), of 37 – by clinical and laboratory parameters. The Random Forest machine learning method was used to determine significance of LN US parameters. The Mean Decline Accuracy criterion was used to quantify the effect of the traits.
Results. There is no US sign indicating a malignant process in the LN with a probability of 100 %. The greatest significance for the diagnosis of LN malignant lesions is a set of criteria: irregular or rounded shape, roundness index, fuzziness and discontinuity of the border, angular contours, impaired differentiation of echostructure and the presence of pathological inclusions, peripheral or mixed types of blood flow. Stratification of the LN US criteria by Lymph- NodeRADS.RU classification types revealed risk of malignancy of categories 1 and 2 in 0 % of cases, category 3–45.1 %, category 4–85.3 %, category 5–96.6 %.
Conclusions. For objective US assessment of surface LN, it is necessary to use a set of both qualitative and quantitative US characteristics. When employing the classification of Lymph-NodeRADS.RU it is necessary to take into account anamnestic and clinical data, especially in the case of a dubious US pattern of LN.

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