COMPARISON OF LINEAR MEASUREMENTS AND VOLUME CHANGES IN RESPONSE TO TREATMENT OF LUNG CANCER

Abstract

The rapid improvements of lung cancer (LC) therapy are ahead of limited methods used in daily practice to evaluate the response to treatment. Standardized RECIST (Response Evaluation Criteria in Solid Tumors) 1.1 approach towards solid tumor response evaluation cannot ensure the detection of early disease progression in some cases. The aim of this study was to analyze the differences between linear measurements and volume changes of measurable tumors in computed tomography (CT) images in response to treatment of LC. Methods. CT scans performed between 2016 and 2019 were analyzed retrospectively. Selection criteria included: verified non-small cells LC (NSCLC); availability of one pre-treatment and two CT scans during treatment; at least one measurable lung tumor. Linear measurement (LM) and volume (V) by an ellipse (VE) and spherical (VS) models of tumor were measured. Manual and semi-automated measurements (VitreaWorkstation™ CAD software) were performed. Size alterations were assessed according to RECIST 1.1: progressive disease (PD), partial response (PR) and stable disease (SD). Results. 125 cases were analyzed. 145 tumors were measured and response to treatment was evaluated. A very strong correlation between LM and VE was found before and during treatment (respectively r=0.921, I r=0.937, II r=0.920). PD was found more often evaluating VE changes in I and II control scans compared to LM changes, respectively 13.79% and 6.9%. Assessing an increase of VE in I control scan, PD frequency was 36.6% (n=53) accordingly matched with PD frequency 35.9% (n=52) detected in II control scan. Conclusion. A very strong correlation between LM and VE was found. An increase in tumor VE could be more sensitive when evaluating lung cancer progression.