Case Report Documents 43-Month Survival After Small-Cell Transformation of EGFR-Mutant Lung Cancer

A single-patient case report from Hebei General Hospital in Shijiazhuang, China, describes prolonged survival after an advanced EGFR-mutant lung adenocarcinoma transformed into small cell lung cancer during treatment. The patient remained alive 43 months after the initial diagnosis, an outcome the authors highlight against the typically poor prognosis associated with this form of treatment resistance.

Transformed small cell lung cancer, abbreviated T-SCLC, is recognized as an important mechanism of acquired resistance to EGFR tyrosine kinase inhibitors, the targeted drugs used in EGFR-mutant non-small cell lung cancer. According to the report, its reported clinical incidence is approximately 3 to 10 percent, and patients who undergo transformation often experience rapid disease progression. No established standard treatment regimen currently exists for this scenario.

The case involved a patient whose tumor carried not only an EGFR mutation but also co-mutations in RB1, TP53, and BRCA2. The report documents this molecular profile as part of the clinical picture of the transformed disease.

Detection of the transformation depended on close surveillance during treatment. The clinical team identified suspicious signs of change and confirmed the histologic conversion by repeat biopsy, which the authors present as the basis for subsequent treatment decisions.

Once small-cell transformation was confirmed, the patient received individualized multimodal therapy rather than a single-line approach. The regimen combined chemotherapy, targeted therapy, and local radiotherapy.

The 43-month survival figure should be read carefully. It represents one patient’s outcome in a case report, not a clinical trial result, and it cannot establish that the multimodal approach caused the prolonged survival. The authors themselves note that no standard regimen exists, which is the context in which they present this documented case.

The report is published in Frontiers in Oncology within its Thoracic Oncology section, with the final formatted version scheduled for publication. The work originates from Hebei General Hospital, and the authors state that all claims expressed in the article are solely their own and do not necessarily represent those of their affiliated organizations or the publisher.

As a single-case account, the report’s scope is limited to describing one patient’s course: the molecular profile, the biopsy-confirmed transformation, the individualized multimodal treatment, and the 43-month survival after initial diagnosis. The authors position the case as a contribution to the documentation of T-SCLC management in a setting without an established standard treatment regimen.

Subject of Research: Small-cell transformation of EGFR-mutant lung adenocarcinoma as a mechanism of EGFR-TKI resistance

Article Title: Prolonged survival after small-cell transformation of EGFR-mutant lung adenocarcinoma: a case report

Article References: Yan, Y., Du, D., Wen, F., Wang, J., & Jia, Y. (2026). Prolonged survival after small-cell transformation of EGFR-mutant lung adenocarcinoma: a case report. Frontiers in Oncology, 16, Article 1975965. https://doi.org/10.3389/fonc.2026.1975965

Image Credits: AI Generated

DOI: 10.3389/fonc.2026.1975965

Keywords: transformed small cell lung cancer, EGFR mutation, EGFR-TKI resistance, lung adenocarcinoma, RB1, TP53, BRCA2, repeat biopsy, multimodal therapy, case report, thoracic oncology, Prolonged