Metastatic Lung Tumors from Colorectal Cancer with <i>EGFR</i> Mutations That Responded to Osimertinib

Abstract

A 50-year-old woman who had previously undergone right hemicolectomy and chemotherapy for colorectal cancer was hospitalized with respiratory failure. Chest computed tomography showed reticulonodular opacities and enlarged lymph nodes. A transbronchial biopsy revealed adenocarcinoma with epidermal growth factor receptor (EGFR) mutations T790M and L861Q. Treatment with the EGFR-tyrosine kinase inhibitor (TKI) osimertinib was started, and she achieved a partial response. We diagnosed her with metastatic lung tumors from colorectal cancer based on additional immunohistochemical staining and the EGFR mutation status (L 861Q) of the specimens. Although cases with EGFR mutations have been rarely reported, an EGFR-TKI can be an effective treatment option for colorectal cancer.

Response to osimertinib in a colorectal cancer patient with an EGFR T790M mutation: A case report

“…The patient had a response for over six months. While there is preclinical evidence for utilizing osimertinib in colon cancer, we could find only one clinical case report of using osimertinib in colon cancer[ 4 , 5 ].…”

“…However, case reports exist describing the efficacy of erlotinib in EGFR mutant colorectal cancer[ 11 , 12 ]. More recently, a 50-year-old Japanese woman with an EGFR T790M lung lesion from a colorectal primary responded to osimertinib for 95 days[ 5 ]. The patient was noted positive for RAS mutant G13D at diagnosis, which is downstream of EGFR .…”

Recent Advances in Therapeutic Strategies to Improve Colorectal Cancer Treatment

“…The liver is the most frequent site of CRC metastasis, and 79% of CRC liver metastases express EGFR (vs. 38% non-metastatic CRC); strategies targeting EGFR are central to the treatment of liver metastatic disease ( Figure 2 ). EGFR is frequently overexpressed but is rarely mutated in CRC, and tyrosine kinase inhibitors (TKIs) targeting mutant-selective EGFR are not effective as single agents for mCRC treatment [ 28 ]. However, two anti-EGFR monoclonal antibodies (mAbs) are widely used for mCRC treatment: (i) cetuximab, a chimeric human–mouse mAb; and (ii) panitumumab, a fully humanized mAb.…”