Table 2.

Univariate and multivariate Cox regression analyses for prediction of progression-free survival (PFS).

Parameters	No.	Event	Median PFS	Log-rank	Univariate analysis		Multivariate analysis
			(95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Age
<65	25	19	7.0(5.9-8.2)	0.318	0.64(0.27-1.54)	0.322	NA
≥65	10	6	15.5(11.0-20.0)
Menopausal status
Pre-menopause	7	6	5.6(5.3-5.9)	0.416	0.68(0.27-1.73)	0.419	NA
Post-menopause	28	20	13.1(3.8-22.4)
Disease-free interval
≤5 y	10	10	3.1(0.0-6.4)	0.047*	0.42(0.17-1.01)	0.054	/	0.052
>5 y	16	11	12.2(1.5-22.9)
Histology of primary breast cancer
Ductal	29	22	9.5(0.1-18.9)	0.593	0.72(0.21-2.43)	0.595	NA
Lobular	4	3	14.7(4.0-20.4)
No. of disease sites
1	16	11	12.2(2.7-21.6)	0.202
2	13	9	13.1(3.7-22.5)		1.13(0.46-2.78)	0.267	NA
≥3	6	6	5.6(4.7-19.7)		2.42(0.86-6.82)
Visceral disease
No	25	19	9.5(1.6-17.5)	0.440	0.71(0.29-1.71)	0.443	NA
Yes	10	7	13.8(0.0-27.7)
Bone only disease
No	30	23	12.2(3.8-20.7)	0.709	1.26(0.24-2.68)	0.710	NA
Yes	5	3	2.4(2.0-2.8)
De novo metastatic disease
No	26	21	7.0(0.0-14.3)	0.167	0.51(0.19-1.36)	0.176	NA
Yes	9	5	18.4(10.9-25.9)
Prior palliative chemotherapy
No	31	22	12.2(3.4-21.0)	0.516	1.43(0.48-4.22)	0.518	NA
Yes	4	4	6.6(0.0-16.8)
Lines of endocrine therapy for MBC
1	28	20	12.2(3.1-21.3)	0.479	1.39(0.55-3.51)	0.482	NA
≥2	7	6	6.6(5.3-7.9)
FDG SUVmax
<4.4	17	12	15.5(9.2-21.8)	0.186	1.72(0.76-3.91)	0.192	NA
≥4.4	18	14	6.6(5.6-7.6)
FES SUVmax
<4.5	17	13	12.2(2.9-21.5)	0.995	0.99(0.45-2.19)	0.995	NA
≥4.5	18	13	7.0(0.0-20.5)
FES/FDG ratio
With FES negative	12	12	5.5(2.3-8.7)	<0.001*		<0.001*		0.006*
<0.96	11	6	29.4 (2.3-56.5)		0.09(0.03-0.32)		0.10(0.02-0.49) 0.27(0.09-0.78)
≥0.96	12	8	14.7 (10.9-18.5)		0.22(0.08-0.59)

PFS, progression-free survival; CI, confidence interval; HR, hazard ratio; MBC, metastatic breast cancer; SUVmax, maximum standard uptake value.

*P ≤ 0.05; N/A: Analysis not performed as univariate analysis not significant.