The development and external validation of an overall survival nomogram in medically inoperable centrally located early-stage non-small cell lung carcinoma

Marloes Duijm, Esther Oomen - de Hoop, N van Voort van d Zyp, P van de Vaart, H Tekatli, Mischa Hoogeman, S Senan, J.J.M.E. Nuyttens

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Web of Science)

Abstract

Background and purpose: Current nomograms predicting survival prognosis after stereotactic body radiation therapy (SBRT) in non-small cell lung cancer (NSCLC) are based on peripherally located tumors. However, patients with a central lung tumor tend to be older, the tumor is often larger and fraction-schedules are risk-adapted. Therefore, we developed and externally validated a nomogram to predict overall survival (OS) in patients having centrally located early-stage NSCLC treated with SBRT. Materials and methods: Patients who underwent SBRT for centrally located NSCLC were identified and baseline characteristics were obtained. A nomogram was built to predict 6-month, 1-, 2- and 3-year OS using Cox proportional hazards model. The model building procedure was validated using bootstrap sampling. To determine generalizability, external validation was performed on a cohort of patients with central NSCLC treated with SBRT from another center. Discriminatory ability was measured with the concordance index (C-index) and calibration plots were used to compare Kaplan–Meier-estimated and nomogram-predicted OS. Results: The nomogram was built on data of 220 patients and consisted of the following variables: PTV, age, WHO performance status, tumor lobe location and ultracentral location. The C-index of the nomogram (corrected for optimism) was moderate at 0.64 (95% confidence interval (CI) 0.59–0.69). Calibration plots showed favorable predictive accuracy. The external validation showed acceptable validity with a C-index of 0.62 (95% CI 0.61–0.64). Discussion: We developed and externally validated the first nomogram to estimate the OS-probability in patients with centrally located NSCLC treated with SBRT. This nomogram is based on 5 patient and tumor characteristics and gives an individualized survival prediction.

Original languageEnglish
Pages (from-to)223-230
Number of pages8
JournalRadiotherapy and Oncology
Volume156
DOIs
Publication statusPublished - Mar 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Research programs

  • EMC OR-01

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