RET fusion–positive non-small cell lung cancer in Sweden: a nationwide registry study

Authors

  • Ella Äng Eklund Department of Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Laboratory Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden https://orcid.org/0000-0002-7962-6836
  • Hans Brunnström Department of Genetics, Pathology, and Molecular Diagnostics, Skåne University Hospital, Lund, Sweden
  • Erik Lampa Epistat AB, Uppsala, Sweden
  • Kerstin Gunnarsson Department of Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Oncology, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
  • Anders Vikström Department of Respiratory Medicine, Linköping University Hospital, Linköping, Sweden
  • Johan Isaksson Centre of Research and Development Region Gävleborg, Uppsala University, Sweden
  • Kristina Lamberg Department of Medical Sciences, Section of Pulmonology, Uppsala University Hospital, Uppsala, Sweden
  • Johan Botling Department of Laboratory Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg; Department of Clinical Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
  • Henrik Fagman Department of Laboratory Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden; Department of Clinical Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
  • Sama I. Sayin Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Center for Cancer Research, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
  • Gunnar Wagenius Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
  • Levent M. Akyurek Department of Laboratory Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden; Department of Clinical Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
  • Anders Berglund Epistat AB, Uppsala, Sweden
  • Volkan I. Sayin Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Center for Cancer Research, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
  • Andreas Hallqvist Department of Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Oncology, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden https://orcid.org/0000-0002-3705-194X

DOI:

https://doi.org/10.2340/1651-226X.2026.46817

Keywords:

Carcinoma, non-small-cell lung, RET, gene fusion, registries, survival analysis, Sweden

Abstract

Background: Rearranged during transfection (RET) fusion–positive non-small cell lung cancer (NSCLC) is a rare but clinically meaningful molecular subgroup. RET inhibitors have demonstrated marked clinical activity; however, real-world data on disease characteristics and outcomes before their widespread introduction remain limited. This study characterizes clinical features, treatment patterns, and survival outcomes of RET fusion–positive NSCLC in a nationwide Swedish cohort, with other driver subgroups as descriptive comparisons.

Methods: Patients ≥18 years diagnosed with histologically confirmed NSCLC in 2018–2022, registered in the Swedish National Lung Cancer Registry and with next-generation sequencing results available, were included. Individuals were categorized by oncogenic driver status, including RET, ALK, BRAF, EGFR, KRAS, ROS1, or wild type. Progression-free survival (PFS) and overall survival (OS) from diagnosis were estimated using Kaplan–Meier methods and standardized Cox proportional hazards models adjusted for age, sex, performance status, smoking, stage, and histology.

Results: A total of 68 patients had RET fusion–positive NSCLC. The RET cohort was characterized by younger age, a high proportion of never-smokers (59%), and predominantly adenocarcinoma histology (96%). Most had stage IV disease at diagnosis and the highest rate of liver metastases (56%). KIF5B–RET (71%) and CCDC6–RET (19%) were the most frequent fusion partners. Adjusted median OS was 28 months (95% confidence interval [CI]: 13–46) for RET, 39 months (95% CI: 29–52) for ALK, and 17–26 months for the other groups, with overlapping CIs.

Conclusion: RET fusion–positive patients were typically younger never-smokers with adenocarcinoma and had encouraging OS, despite limited access to selective RET inhibitors during the study period.

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Published

2026-10-29

How to Cite

Äng Eklund, E., Brunnström, H., Lampa, E., Gunnarsson, K., Vikström, A., Isaksson, J., … Hallqvist, A. (2026). RET fusion–positive non-small cell lung cancer in Sweden: a nationwide registry study. Acta Oncologica, 65, 875–883. https://doi.org/10.2340/1651-226X.2026.46817

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Vol. 65 (2026): Acta Oncologica

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Original article

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Copyright (c) 2026 Ella Äng Eklund, Hans Brunnström, Erik Lampa, Kerstin Gunnarsson, Anders Vikström, Johan Isaksson, Kristina Lamberg, Johan Botling, Henrik Fagman, Sama I. Sayin, Gunnar Wagenius, Levent M. Akyurek, Anders Berglund, Volkan I. Sayin, Andreas Hallqvist

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