Individualized management strategies for advanced non-small cell lung cancer with EGFR exon 19 deletion - A case report

Sep 30, 2026

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Advanced metastatic lung adenocarcinoma case study evaluating individualized treatment for concurrent EGFR exon 19 deletion (19del) and L861Q compound mutations using tyrosine kinase inhibitors. Circulating tumor DNA (ctDNA) monitoring enabled dynamic molecular assessment: increases in total ctDNA and a rising EGFR C797S allele fraction indicated molecular progression before radiographic changes. Progression-free survival reached 11 months, highlighting ctDNA’s role in real-time treatment monitoring and supporting further development of precise strategies and novel therapies.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages7

Reading Time18 min

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Abstract

Introduction

EGFR mutations in NSCLC

Rare and compound EGFR mutations

Treatment rationale and ctDNA monitoring

ONCOLOGY LETTERS 31: 88, 2026 Individualized management strategies for advanced non‑small cell lung cancer withEGFR exon 19 deletion and L861Q compound mutations based on circulating tumor DNA monitoring: A case report XIAOBANG ZHU 1* , YE SUN 1* , RUIRUI CAI 1 , WENBIN ZHANG 1 , XIANGWEI ZHANG 1 , AILING SONG 1 , XIAOYAN CHEN2 , CUICUI LIU3 and JIANPING ZHOU2,4,5 1 Department of Respiratory and Critical Care Medicine, Wuxi Branch, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Wuxi, Jiangsu 214000, P.R. China; 2Department of Pathology, Wuxi Branch, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Wuxi, Jiangsu 214000, P.R. China; 3Geneseeq Research Institute, Nanjing Geneseeq Technology Inc. , Nanjing, Jiangsu 210032, P.R. China; 4Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China; 5 Institute of Respiratory Diseases, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China Received June 20, 2025; Accepted November 4, 2025 DOI: 10. 3892/ol.2025.15441 Abstract. Epidermal growth factor receptor (EGFR) muta‑ tions are major oncogenic drivers in non‑small cell lung cancer (NSCLC) . These alterations, particularly prevalent in lung adenocarcinoma among the Chinese population, include the exon 19 deletion (19del), L858R point mutation and the less frequent L861Q variant. However, to the best of our knowledge, no standardized treatment regimen exists for patients harboring both common and rare EGFR mutations. The current study presents a case of advanced metastatic lung adenocarcinoma with concurrent EGFR 19del and L861Q mutations, managed with tyrosine kinase inhibitors targeting Correspondence to: Dr Jianping Zhou, Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Huangpu, Shanghai 200025, P.R. China E‑[mail: zjp11593@rjh.com.cn](mail: zjp11593@rjh.com.cn) *Contributed equally Abbreviations: ADC, antibody‑drug conjugate; CSCO, Chinese Society of Clinical Oncology; ctDNA, circulating tumor DNA; EGFR, epidermal growth factor receptor; NSCLC, non‑small cell lung cancer; MRD, minimal residual disease; NCCN, National Comprehensive Cancer Network; NGS, next‑generation sequencing; PFS, progression‑free survival; RECIST, Response Evaluation Criteria in Solid Tumors; TKI, tyrosine kinase inhibitor; TROP2, tumor‑associated calcium signal transducer 2; TTF‑1, thyroid transcription factor‑1; VUS, variant of unknown significance; 19del, exon 19 deletion Key words: EGFR mutation, NSCLC, ctDNA, almonertinib, ADC EGFR and dynamic plasma circulating tumor DNA (ctDNA) monitoring. The patient achieved a progression‑free survival time of 11 months. Serial plasma ctDNA monitoring detected molecular progression, characterized by an increase in total ctDNA and a rising EGFR C797S allele fraction, prior to radio‑ graphic changes. The present case emphasized the importance of individualized management and the key role of ctDNA in real‑time treatment monitoring, offering a potentially novel approach for precise disease evaluation in the future. Further research and the development of novel therapies are warranted to potentially improve outcomes in patients with advanced EGFR‑mutated NSCLC. Introduction Epidermal growth factor receptor (EGFR) mutations are majoroncogenic drivers in non‑small cell lung cancer (NSCLC) . In the Chinese NSCLC population, ~28.2% of patients harbor EGFR mutations, with their prevalence in lung adenocarci‑ noma exceeding 50%(1). The most common EGFR mutations, exon 19 deletion (19del) and the L858R point mutation, account for ~85% of cases, while the remaining 15% are rare, highly heterogeneous mutations occurring at low frequen‑ cies (2). Rare mutations frequently respond poorly to standard targeted therapies, and evidence guiding treatment for pat

FAQs

What EGFR mutations are reported in this case?

The case involves concurrent EGFR exon 19 deletion (19del) and the L861Q variant, described as a compound mutation in advanced lung adenocarcinoma.

How was circulating tumor DNA (ctDNA) used to monitor progression?

Serial plasma ctDNA monitoring detected molecular progression through increased total ctDNA and a rising EGFR C797S allele fraction before radiographic changes.

What treatment outcome was observed?

The patient achieved a progression-free survival time of 11 months under the individualized tyrosine kinase inhibitor–based management approach.

Sep 30, 2026

Uploaded by Rizky