Frontiers in Oncology (Sep 2020)

Validation of Nine Different Prognostic Grading Indexes for Radiosurgery of Brain Metastases in Breast Cancer Patients and Development of an All-Encompassing Prognostic Tool

  • Fabian Weykamp,
  • Fabian Weykamp,
  • Fabian Weykamp,
  • Rami A. El Shafie,
  • Rami A. El Shafie,
  • Rami A. El Shafie,
  • Laila König,
  • Laila König,
  • Laila König,
  • Katharina Seidensaal,
  • Katharina Seidensaal,
  • Katharina Seidensaal,
  • Tobias Forster,
  • Tobias Forster,
  • Tobias Forster,
  • Nathalie Arians,
  • Nathalie Arians,
  • Nathalie Arians,
  • Sebastian Regnery,
  • Sebastian Regnery,
  • Sebastian Regnery,
  • Philipp Hoegen,
  • Philipp Hoegen,
  • Philipp Hoegen,
  • Thomas M. Deutsch,
  • Andreas Schneeweiss,
  • Jürgen Debus,
  • Jürgen Debus,
  • Jürgen Debus,
  • Jürgen Debus,
  • Jürgen Debus,
  • Jürgen Debus,
  • Juliane Hörner-Rieber,
  • Juliane Hörner-Rieber,
  • Juliane Hörner-Rieber,
  • Juliane Hörner-Rieber

DOI
https://doi.org/10.3389/fonc.2020.01557
Journal volume & issue
Vol. 10

Abstract

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Purpose: Several prognostic indexes for overall survival (OS) after radiotherapy of brain metastases in breast cancer patients exist but are mainly validated for whole-brain radiotherapy or not specifically for breast cancer patients. To date, no such index provides information beyond mere OS.Methods: We retrospectively analyzed 95 breast cancer patients treated with stereotactic radiosurgery for 203 brain metastases. The Kaplan–Meier method with log-rank test was used to assess OS, local control (LC), distant cranial control (DCC), and extracranial control (EC). Cox regression was applied to detect prognostic outcome factors. A point scoring system was designed to stratify patients based on outcome. Nine established prognostic indexes were analyzed using the concordance index (c-index).Results: Two out of nine analyzed prognostic indexes for OS showed a significant c-index, the breast graded prognostic assessment (bGPA; 0.631; 95% CI, 0.514–0.748; p = 0.037) and the modified bGPA (mod-bGPA; 0.662; 95% CI, 0.547–0.777; p = 0.010). Significant results from multivariate analysis (Karnofsky Performance Score, Her2/neu receptor status, extracranial control) were used to generate a new point system: the breast cancer stereotactic radiotherapy score (bSRS), which discriminated three significantly different prognostic groups, for LC, DCC, EC, and OS, respectively. However, the c-index was only significant for OS (0.689; 95% CI, 0.577–0.802; p = 0.003).Conclusions: The new bSRS score was superior to the bGPA and mod-bGPA scores for prognosis of OS. The bSRS is easy to use and the first tool, which might also provide outcome assessment beyond mere OS. Future studies need to validate these findings.

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