BMC Cancer 2009, 9:154 http://www.biomedcentral.com/1471-2407/9/154 Table 4: Analysis for OS of patients according to hormone receptor status Variables Age < 40 yr Postmenopausal state HER2 positive DFI* > 2 yr Initial stage IV Sum of metastasis sites ≥ 3 Visceral metastasis BP** use HR positive patients HR negative patients Univariate Multivariate Univariate Multivariate Hazard ratio (95% CI) P-value Hazard ratio (95% CI) P-value Hazard ratio (95% CI) P-value Hazard ratio (95% CI) P-value 0.85 (0.60–1.19) 1.26 0.81–1.94) 1.66 (1.15–2.40) 0.76 (0.54–1.07) 0.76 (0.49–1.19) 1.32 (0.94–1.83) 1.78 (1.28–2.48) 0.67 (0.42–1.19) 0.344 0.302 0.007 0.12 0.232 0.105 0.001 0.111 - - - - 1.54 (1.06–2.23) - 1.7 (1.22–2.38) - - - - - - - 0.022 0.002 0.75 (0.47–1.21) - 0.67 (0.43–1.06) 0.61 (0.38–0.98) 0.96 (0.58–1.59) 1.83 (1.13–2.97) - 0.56 (0.34–0.91) 0.237 - - 0.088 0.040 0.882 0.014 0.019 - - - 0.59 (0.36–0.97) - 1.70 (1.04–2.78) - 0.50 (0.30–0.83) - - - - - 0.036 0.034 0.007 Abbreviations: *, disease free interval; **, bisphosphonate. cant difference in the baseline characteristics between the BP and the non-BP groups, except that more patients had weight bearing bone metastases in the BP group com- pared to the non-BP group (P < 0.001) (Table 3). The rate of disease progression in bone metastases and SREs (except for the first event) was greater in the BP group. However, the difference was not significant (P = 0.14, P = 0.29, respectively). TTP_BD was not significantly different between the two groups (Fig. 3). Unlike the OS observed in the HR positive patients, OS was significantly prolonged in the BP group (median, 1.7 yr vs. 1.3 yr, P = 0.040, Fig. 3). In univariate analysis for OS, disease free interval > 2 years (hazard ratio = 0.61 [95% CI 0.38 to 0.98], P = 0.040), a sum of metastatic sites ≥ 3 (hazard ratio = 1.83 [95% CI 1.13 to 2.97], P = 0.014), and BP treatments (hazard ratio = 0.56 [95% CI 0.34 to 0.91], P = 0.019) were significant factors for sur- vival in HR negative patients. These results were verified through multivariate analysis (Table 4). PFaigtiuenrets 3with HR negative metastatic bone disease Patients with HR negative metastatic bone disease. (A) TTP_BD (P = 0.163), (B) OS (P = 0.040). Page 6 of 9 (page number not for citation purposes)