Evaluation of Volumetric Lymph Node Measurements in Cutaneous T-Cell Lymphoma Patients Enrolled in the Mavoric Trial: An Interim Analysis

Abstract

Lymph node assessment is an important component of staging, classification, and treatment response assessment in cutaneous T-cell lymphoma (CTCL). Although a biopsy is the only definitive way to assess nodal involvement, radiologic evaluation is commonly used in practice given its practicality. Current radiologic criteria are adapted from guidelines for lymphomas with primarily nodal involvement and have not been validated in CTCL patients. These criteria are limited by linear measurements which fail to accurately capture small and/or asymmetric nodal involvement in CTCL and may lead to flawed estimations of the overall disease burden. Furthermore, unidimensional and bidimensional measurements are subject to significant inter- and intra-observer variability. More accurate methods of lymph node evaluation are needed to improve risk stratification and treatment response assessment in CTCL. Recent advances in digital imaging techniques have made it possible to obtain volumetric tumor measurements. This technique has shown promise as a more accurate imaging biomarker than unidimensional measurements in several solid cancer types, offering improved sensitivity for changes in tumor burden during treatment. Volumetric lymph node measurements have been shown to be superior to unidimensional measurements in distinguishing between benign and malignant lymph nodes in systemic lymphoma, however volumetric measurements have never been studied in CTCL. The aim of this study was to assess the utility of volumetric lymph node measurements in CTCL using this novel imaging technique. We analyzed imaging and clinical data from the mogamulizumab versus vorinostat in previously treated cutaneous T-cell lymphoma (MAVORIC) trial which included 372 CTCL patients randomized to receive either mogalizumab or vorinostat. The majority of patients randomized to vorinostat crossed over to mogalizumab due to disease progression or intolerance. As part of the trial, patients underwent computed tomography (CT) scans at baseline and regular follow-up intervals to assess for lymph node response to treatment. In our study, target lymph nodes in serial CT scans were measured by a team of radiologists using a response assessment system built on open-source software known as the Weasis imaging platform. Semi-automated segmentation algorithms were used to quantify unidimensional and bidimensional measurements as well as lymph node volumes. Our preliminary data suggests that there is a correlation between unidimensional, bidimensional, and volumetric lymph node measurements. For the first time, we validate volumetric lymph node measurement as a viable method of lymph node assessment in CTCL. This implicates lymph node volume as an alternative metric for lymph node assessment in CTCL that has the potential to improve the accuracy of current nodal assessment criteria. Additional research is underway to determine whether volumetric lymph node measurements are superior to uni- and bidimensional measurements in assessing treatment response and predicting clinical outcomes in CTCL.