Liquid Biopsy Response Evaluation Criteria in Solid Tumors (LB-RECIST)

Gouda MA (1), Janku F (2), Wahida A (3), Buschhorn L (3), Schneeweiss A (3), Abdel Karim N (4), De Miguel Perez D (5), Del
Re M (6), Russo A (7), Curigliano G (8,9), Rolfo C (6), Subbiah V (10)
(1) Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston
(2) Monte Rosa Therapeutics, Boston, USA
(3) Division of Gynecological Oncology, National Center for Tumor Diseases (NCT), Heidelberg, Germany
(4) Inova Schar Cancer Institute, Fairfax
(5) University of Virginia, Charlottesville
(6) Center for Thoracic Oncology, Icahn School of Medicine at Mount Sinai, New York, USA
(7) Medical Oncology Unit, Papardo Civil Hospital and Department of Human Pathology, University of Messina, Messina
(8) Department of Oncology and Hemato-Oncology, University of Milano, Milano
(9) Division of Early Drug Development for Innovative Therapies, European Institute of Oncology, IRCCS, Milano, Italy
(10) Sarah Cannon Research Institute, Nashville, USA

Current evaluation of treatment response in solid tumors depends on dynamic changes in tumor diameters as measured by imaging. However, these changes can only be detected when there are enough macroscopic changes in tumor volume, which limits the usability of radiological response criteria in evaluating earlier stages of disease response and necessitates much time to lapse for gross changes to be notable. One promising approach is to incorporate dynamic changes in circulating tumor DNA (ctDNA), which occur early in the course of therapy and can predict tumor responses weeks before gross size changes manifest. However, several issues need to be addressed before recommending the implementation of ctDNA response criteria in daily clinical practice such as clinical, biological, and regulatory challenges and, most importantly, the need to standardize/harmonize detection methods and ways to define ctDNA response and/or progression for precision oncology. Herein, we review the use of liquid biopsy (LB) to evaluate response in solid tumors and propose a plan toward standardization of LB-RECIST.