Case Report
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Oct 15, 2023; 15(10): 1829-1834
Published online Oct 15, 2023. doi: 10.4251/wjgo.v15.i10.1829
Response to osimertinib in a colorectal cancer patient with an EGFR T790M mutation: A case report
Blake Buzard, Lindsey Douglass, Beth Gustafson, Jennifer Buckley, Marc Roth, Lara Kujtan, Dhruv Bansal
Blake Buzard, Lindsey Douglass, Beth Gustafson, Jennifer Buckley, Marc Roth, Cancer Institute, St. Luke's Hospital, Kansas, MO 64111, United States
Lara Kujtan, Department of Medical Oncology, University of Missouri - Kansas City, Kansas, MO 64108, United States
Dhruv Bansal, Department of Hematology/Oncology, St. Luke's Cancer Institute, Kansas, MO 64111, United States
Author contributions: All authors contributed to manuscript writing; all authors have read and approved the final manuscript.
Informed consent statement: Consent for this publication was received from the patient’s legal guardian.
Conflict-of-interest statement: The authors declare no conflicts of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Lara Kujtan, MD, Associate Professor, Department of Medical Oncology, University of Missouri - Kansas City, No. 2310 Holmes St, Kansas, MO 64108, United States. kujtanl@umsystem.edu
Received: July 21, 2023
Peer-review started: July 21, 2023
First decision: August 23, 2023
Revised: September 6, 2023
Accepted: September 18, 2023
Article in press: September 18, 2023
Published online: October 15, 2023
Processing time: 80 Days and 11.6 Hours
Core Tip

Core Tip: Somatic epidermal growth factor receptor (EGFR) mutations are rarely found in colorectal cancer. Treatment with anti-EGFR antibodies is commonplace, but EGFR tyrosine kinase inhibitors are not standard in colorectal cancer. Here we report a case of sustained response to osimertinib in a metastatic colorectal cancer patient with an EGFR T790M mutation detected with cell-free DNA. She progressed on three lines of treatment, and received fourth-line treatment with off-label osimertinib, with clinical response. She received treatment with osimertinib for seven months. This case shows the benefit of multi-gene sequencing assays to identify potential therapeutic options in patients with refractory disease.