|Background: Prognostic scores might be useful tools both in clinical practice and clinical trials,
where they can be used as stratification parameter. The available scores for patients with brain
metastases have never been tested specifically in patients with primary breast cancer. It is therefore
unknown which score is most appropriate for these patients.
Methods: Five previously published prognostic scores were evaluated in a group of 83 patients
with brain metastases from breast cancer. All patients had been treated with whole-brain
radiotherapy with or without radiosurgery or surgical resection. In addition, it was tested whether
the parameters that form the basis of these scores actually have a prognostic impact in this
biologically distinct group of brain metastases patients.
Results: The scores that performed best were the recursive partitioning analysis (RPA) classes and
the score index for radiosurgery (SIR). However, disagreement between the parameters that form
the basis of these scores and those that determine survival in the present group of patients and
many reported data from the literature on brain metastases from breast cancer was found. With
the four statistically significant prognostic factors identified here, a 3-tiered score can be created
that performs slightly better than RPA and SIR. In addition, a 4-tiered score is also possible, which
performs better than the three previous 4-tiered scores, incl. graded prognostic assessment (GPA)
score and basic score for brain metastases (BSBM).
Conclusion: A variety of prognostic models describe the survival of patients with brain metastases
from breast cancer to a more or less satisfactory degree. However, the standard brain metastases
scores might not fully appreciate the unique biology and time course of this disease, e.g., compared
to lung cancer. It appears possible that inclusion of emerging prognostic factors will improve the
results and allow for development and validation of a consensus score for broad clinical application.
The model that is based on the authors own patient group, which is not large enough to fully
evaluate a large number of potential prognostic factors, is meant to illustrate this point rather than
to provide the definitive score.