Volumetric Tumor Response and Progression in EGFR-mutant NSCLC Patients Treated with Erlotinib or Gefitinib

Abstract

Objective Investigate the association between 8-week tumor volume decrease and survival in an independent cohort of EGFR-mutant advanced non-small-cell lung cancer (NSCLC) patients treated with first-line erlotinib or gefitinib, and assess the rate of their volumetric tumor growth after the volume nadir. Methods In patients with advanced NSCLC harboring sensitizing EGFR mutations treated with first-line erlotinib or gefitinib, CT tumor volumes of dominant lung lesions were analyzed for 1) the association with survival, and 2) volumetric tumor growth rate after the volume nadir. Results In 44 patients with the 8-week follow-up CT, the 8-week tumor volume decrease (%) was significantly associated with longer overall survival (OS) when fitted as a continuous variable in a Cox model (p=0.01). The growth rate of the logarithm of tumor volume (logeV), obtained using a linear mixed-effects model adjusting for time since baseline, was 0.096/month (SE:0.013/month; 95%CI:0.071-0.12/month), which was similar to the rate of 0.12/month (SE:0.015/month; 95%CI: 0.090-0.15/month) observed in the previous report. Conclusions The 8-week tumor volume decrease was validated as a marker for longer survival in the independent cohort of EGFR-mutant NSCLC patients treated with first-line erlotinib or gefitinib. Volumetric tumor growth rate after the nadir in this cohort was similar to that of the previous cohort, indicating the reproducibility of the observation among different patient cohorts.

Tumor Response Dynamics of Advanced Non–small Cell Lung Cancer Patients Treated with PD-1 Inhibitors: Imaging Markers for Treatment Outcome

“…As tumor volume has also been shown to be a reproducible marker to characterize tumor response and progression and predict survival for advanced NSCLC treated with molecular targeted therapy including EGFR inhibitors(33,35,36), the utility of tumor volume in the setting of immune-related response evaluations can be tested in future studies. The response assessment of irRECIST is based on the sum of the target lesion measurements in each patient, and does not reflect different behaviors of individual lesions in one patient.…”

Monitoring immune-checkpoint blockade: response evaluation and biomarker development

“…Radiographic assessments during therapy provide quantitative data on tumour dynamics that have been found to be associated with the response to and outcomes of precision cancer therapies 84–86 , and might be useful to classify patients into subgroups according to different immune-related response patterns, with different prognostic implications 25 . Importantly, noninvasive functional imaging strategies need to be developed in the future to visualize and quantify target cells and molecules in vivo .…”

Pharmacometric Modeling of Liver Metastases' Diameter, Volume, and Density and Their Relation to Clinical Outcome in Imatinib‐Treated Patients With Gastrointestinal Stromal Tumors

“…Moreover, volume-based criteria tended to be better associated to OS than RECIST. Noteworthy, longitudinal analysis of tumor volume on a continuous scale are only rarely reported 21 ; most published results are based on landmark analyses, in which the correlation between the often-categorized change in tumor burden after a fixed treatment duration and clinical outcome is investigated, resulting in a loss of information.…”

“…The estimated ellipsoidal volume has been suggested as an approximation for software‐calculated actual volume to overcome limitations related to software availability and has shown good correlation to actual volume 15, 18. Moreover, for a number of cancers 3D assessments enable to capture finer changes in tumor size,17, 18 and better correlates to long‐term clinical outcome, such as OS,2, 18, 21 compared to 1D measurements. Such results were supported by Schiavon et al .,15 showing that ellipsoidal volume provides a satisfactory approximation for the actual volume of liver metastases in imatinib‐treated GIST.…”