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                                CHAPTER V
To illustrate the effects of discerning between receptor positive and triple negative breast cancer, the cohort was stratified into three categories according to a previously published predictive model9, both before and after adjusting the primary tumor classification. Before adjustment, all breast cancer patients were considered to have a ‘favorable clinical profile’. The current results, however, suggest that triple negative breast cancer should be considered as having a ‘moderate clinical profile’, since a median survival of 5.5 months is in line with survival times described in this category. Receptor positive breast cancer remains in the ‘favorable’ category. The number of patients in category A decreased from 32 (29%) to 27 (25%) and the median survival time has risen from 31.2 months (95%CI 14.6-47.9) to 39.6 months (95%CI 19.2-60.0). Patients with a triple negative phenotype have been assigned to categories B and C, decreasing median survival times in those categories slightly (table 3).The C-statistic before the adjustment was 0.61 and after the adjustment 0.64, suggesting an improvement in the accuracy of the model.
Table 3. Median survival times before and after model adjustment for molecular phenotype. MOS: median overall survival. HR: hazard ratio. CI: confidence interval.
  Predictive Category
    N (%)
  MOS (95%CI)
    HR
   95%CI
   p-value
 Before adjustment
A 32 (29)
B 48 (44)
C 30 (27)
D None
After adjustment
A 27 (25)
B 51 (46)
C 32 (29)
D None
DISCUSSION
31.2 (14.6-47.9) - - 15.9 (8.7-23.1) 1.8 1.0-3.1 9.8 (7.6-12.0) 2.7 1.5-4.9
N/A N/A N/A
39.6 (19.2-60.0) - - 14.7 (9.9-19.5) 2.5 1.3-4.7 9.3 (7.1-11.5) 3.8 1.9-7.3
N/A N/A N/A
0.007 0.046 0.002 N/A
0.001
0.004 <0.001 N/A
 In this international multi-center retrospective study of 111 patients treated for symptomatic SBM caused by breast cancer, it is shown that, even though the disease has progressed up to end stage disease, patients with a triple negative phenotype have a much shorter median survival time (5.5 months, 95%CI 2.0-9.0) than patients with a receptor positive phenotype (23.4 months, 95%CI 19.0-27.8). This suggests that models estimating survival in patients with symptomatic SBM should at least differentiate between these two types of breast cancer.
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