High-dose reirradiation of in-field recurrence lung cancer in the THOrax (RETHO): toxicity analysis of a prospective trial
In brief
Lung cancer reirradiation caused grade 3 toxicity in 17%; none had grade 4-5 events
In this prospective trial of 60 patients receiving high-dose reirradiation for recurrent lung cancer, 10 developed grade 3 toxicity, including 7 with radiation pneumonitis; no grade 4 or 5 toxicity occurred over a median 26 months. Higher cumulative lung dose measures were linked to moderate or severe pneumonitis, so careful dose planning remains key.
- Journal
- International journal of radiation oncology, biology, physics (Q1)
- Published
- 2 November 2026
- Study design
- Non-randomized / quasi-experimental trial
- Evidence level
- Level 2, Moderate (CEBM 2b)
- Authors
- Dr M Duijm, E Cammareri, Dr P V Granton, W Schillemans, Dr S Petit, Dr J Belderbos, et al.
- PMID
- 42971440
- DOI
- 10.1016/j.ijrobp.2026.10.021
Why clinicians should know about it
- Picked for Medical Physics (paper of the day, 4 November 2026): Prospective reirradiation study reports cumulative dose and toxicity associations
- Picked for Radiation Oncology (paper of the day, 3 November 2026): Prospective thoracic reirradiation trial; toxicity and cumulative dose constraints
Abstract
INTRODUCTION: This prospective phase II XXX trial evaluated high-dose thoracic reirradiation for in-field recurrent lung cancer while respecting the cumulative dose to the organs at risk. Here, we report the toxicity and dosimetric results of the XXX trial. METHODS: Patients with recurrent lung cancer within 5cm of the previously irradiated high-dose region (50Gy10 EQD2) were eligible. Patients were treated in a radical setting (≥45Gy10 EQD2) using conventionally (chemo)radiotherapy or stereotactic radiotherapy. Cumulative dose constraints were: tracheobronchial tree Dmax 110Gy3 EQD2, esophagus Dmax 100Gy3 EQD2 and spinal cord Dmax 75Gy3 EQD2. All doses were converted to EQD2 using α/β values of 10Gy (Gy10) for the tumor or acute effects and 3Gy for late effects (Gy3). RESULTS: Sixty patients were included. Thirty-eight patients were reirradiated with conventionally (chemo)radiotherapy most commonly 50Gy in 25 fractions or 60Gy in 30 fractions, while 22 patients received stereotactic radiotherapy most commonly 52.5Gy in 7 fractions. After a median follow-up of 26 months, no grade 4-5 toxicity was reported. Ten patients (17%) experienced grade 3 toxicity, including 7 cases of radiation pneumonitis. Dosimetric data were available for 59 patients. Median prescribed reirradiation dose was 60Gy10 EQD2, resulting in a median cumulative PTV Dmax of 130Gy10 EQD2. The cumulative esophagus dose exceeded 80Gy3 in 20 patients, cumulative trachea dose exceeded 80 Gy3 in 26 patients and cumulative bronchus dose exceeded 100Gy3 in 26 patients. Both cumulative lung V20 and cumulative mean lung dose were significantly associated with grade 2-3 radiation pneumonitis (p-value <0.05), whereas cumulative V5 was not. CONCLUSION: Thoracic reirradiation with a radical dose to the tumor while respecting cumulative organs at risk constraints was feasible in this prospective trial. Grade 2-3 radiation pneumonitis was associated with cumulative mean lung dose and cumulative lung V20. No grade 4-5 esophageal, airway or spinal cord toxicity occurred despite high cumulative doses.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.