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Publications

Journal Article Ahead of print

PubMed: 42503335 DOI: 10.1016/j.radonc.2026.111713

External validation of dose to heart substructures and the association with non-cancer death after SBRT in stage I-II NSCLC patients.

Radiother Oncol

Authors: Barbara Stam, Robin Wijsman, Maria Thor, Andreas Rimner, Joseph O Deasy, Jose Belderbos, Jan-Jakob Sonke

Affiliations

  • Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
  • Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
  • Department of Medical Physics, Memorial Sloan Kettering Cancer Center, NY, USA.
  • Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany.
  • Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
  • Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.

Abstract

BACKGROUND

We use two independent cohorts to externally validate a published model describing the association between non-cancer death (nonCAdeath) and cardiac dose in patients with early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT).

METHODS

The published model included age, performance status, baseline lung function, baseline cardiac condition, and dose to the left atrium and superior vena cava. The two validation cohorts consisted of 221 and 217 early-stage NSCLC patients. Validation of the Cox-based nonCAdeath model focused on assessing calibration and discrimination. A nomogram was built based on the nonCAdeath model to assess clinical impact at 24 months. In parallel, to account for discrepancies in outcome definition, an overall survival model was built using the original derivation cohort (N = 803) and validated as well.

RESULTS

the published nonCAdeath model generalized in one cohort with similar nonCAdeath definition, and the parallel overall survival model validated in both cohorts; the prognostic index was not significantly different between the derivation cohort and validation cohorts, discrimination was comparable across all three cohorts. For the cohorts that validated, the predictions overlapped well with the observed survival, and Hazard ratios for risk groups were comparable between derivation and validation cohorts. The nomogram indicates that for an average patient with a high cardiac dose (22 Gy), a 36% cardiac dose reduction could decrease the risk of nonCAdeath at 24 months by 1%.

CONCLUSION

The model that describes the association between cardiac dose parameters, baseline clinical parameters and nonCAdeath after SBRT was externally validated in the cohort with similar outcome definition, while the parallel model with overall survival as endpoint validated in both cohorts. The results from this observational validation study strengthen the robustness of the nonCAdeath model guidance for cardiac sparing.

MeSH

Radiotherapy, Lung, Nomograms, Heart, Neoplasms, Carcinoma, Non-Small-Cell Lung, Medical Oncology