158P - PET/CT based imaging biomarkers for response prediction of stage IV NSCLC treated with paclitaxel–carboplatin–bevacizumab with or without nitroglyc...

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Anti-Cancer Agents & Biologic Therapy
Non-Small-Cell Lung Cancer, Metastatic
Translational Research
Presenter Evelyn de Jong
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors E.E.C. de Jong1, W. Van Elmpt1, R.T.H. Leijenaar1, H. Groen2, E. Smit3, R. Boellaard4, V. Van der Noort5, E.G.C. Troost6, P. Lambin1, A. Dingemans7
  • 1Department Of Radiation Oncology (maastro), Grow-school For Oncology And Developmental Biology, Maastricht University Medical Center (MUMC), 6229ET - Maastricht/NL
  • 2Department Of Pulmonary Diseases, University Hospital Groningen (UMCG), 9700 RB - Groningen/NL
  • 3Pulmonary Diseases, VUMC, 1007 MB - Amsterdam/NL
  • 4Department Of Nuclear Medicine And Molecular Imaging, University Hospital Groningen (UMCG), Groningen/NL
  • 5Department Of Biometrics, The Netherlands Cancer Institute Antoni van Leeuwenhoek Hospital, Amsterdam/NL
  • 6Department Of Radiation Oncology (maastro), Grow-school For Oncology And Developmental Biology, Institute of Radiooncolog, Helmholtz-Zentrum Dresden-Rossendorf, 6229ET - Dresden/DE
  • 7Pulmonology, Maastricht University Medical Center (MUMC), 6202 AZ - Maastricht/NL

Abstract

Background

To predict early response to treatment, various imaging biomarkers defined on repeated [18F] FDG-PET/CT imaging were investigated in a randomized phase II study in patients with stage IV non-small cell lung cancer (NSCLC) receiving paclitaxel-carboplatin-bevacizumab with or without nitroglycerin patches (NCT01171170). The hypothesis was that changes within the tumor, due to response to treatment, are visible earlier on PET than on CT. PET-based imaging biomarkers could therefore enable identification of responders at an earlier time-point than CT-based parameters.

Methods

For 60 patients in the trial, two PET/CT scans were available, one at baseline and one at week 3. For these patients, the primary tumor volume was delineated and used as the volume of interest for calculating the imaging biomarkers. Response of the primary tumor was assessed at week 3 using a 15% and 30% decrease in CT diameter, CT volume, SUVmax, SUVmean, SUVpeak and Total Lesion Glycolysis (SUVmean x CT volume). The change in imaging biomarkers at week 3 was compared to true response, defined by RECIST response at week 6, by calculating the sensitivity and specificity as well as the area-under-curve (AUC).

Results

There were more PET-based responders in week 3 than CT-based responders. Furthermore, PET showed a high sensitivity whereas CT showed a high specificity (Table 1). PET parameters (max and peak SUV) reached a significant AUC to predict RECIST analysis. 158PT1 Table 1.

 30%-based15%-basedROC characteristics
 % respondersSensitivitySpecificity% respondersSensitivitySpecificityAUCp-value
CT diameter18%27%84%45%47%56%0.5760.379
CT volume65%73%38%77%87%27%0.6160.180
SUVmax68%80%36%87%100%18%0.6710.049
SUVmean72%93%36%88%100%16%0.6410.103
SUVpeak73%93%33%90%100%13%0.6890.030
TLG83%100%22%90%100%13%0.6460.093

Conclusions

The higher number of PET responders combined with the higher AUC values compared to CT indicates that PET is able to predict treatment response earlier than CT, though typically at a lower specificity. The next step will be to define the optimal thresholds for better response prediction including the combination of PET-based and CT-based criteria together with clinical variables.

Clinical trial identification

NCT01171170

Legal entity responsible for the study

A.-M. C. Dingemans

Funding

Dutch Cancer Society

Disclosure

All authors have declared no conflicts of interest.