Evaluation of tumour heterogeneity by 18F-fluoroestradiol PET as a predictive measure in breast cancer patients receiving palbociclib combined with endocrine treatment

Table 2 Univariate and multivariate Cox regression analyses for prediction of PFS for the entire patients

Parameters	No	Event	Median PFS	Log-rank	Univariate analysis		Multivariate analysis
Parameters	No	Event	(95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Disease-free interval
≤ 5 y	22	11	23.9(1.6–46.3)	0.366	1.40(0.67–2.89)	0.369	NA
> 5 y	31	22	15.6(10.1–21.1)
No. of disease sites
1	18	13	12.0(0.9–23.1)	0.690
2	20	12	12.1(0.6–23.6)	0.690	0.89(0.41–1.97)	0.789	NA
≥ 3	18	9	23.9(14.6–33.2)		0.69(0.29–1.63)	0.397	NA
Visceral disease
No	30	20	12.0(6.4–17.6)	0.191	0.64(0.32–1.26)	0.196	NA
Yes	26	14	23.9(14.4–33.3)	0.191	0.64(0.32–1.26)	0.196	NA
Lines of therapy prior to palbociclib
0	38	19	21.6(12.6–30.6)		0.33(0.12–0.93)	0.036*
1	9	6	23.6(7.8–39.4)	0.005*	0.29(0.13–0.65)	0.003*	/	0.170
≥ 2	9	9	4.2(3.8–4.7)
Types of endocrine therapy
palbociclib + fulvestrant	37	25	12.8(7.0–18.7)	0.186	0.60(0.28–1.29)	0.192	NA
palbociclib + letrozole	19	9	26.5(4.5.7–48.5)	0.186	0.60(0.28–1.29)	0.192	NA
Presence of FES-negative lesions
Yes	10	10	2.4(1.1–3.7)	< 0.001*	0.04(0.01–0.13)	< 0.001*	0.04(0.01–0.13)	< 0.001*
No	46	24	23.6(15.8–31.4)	< 0.001*	0.04(0.01–0.13)	< 0.001*	0.04(0.01–0.13)

PFS Progression-free survival; CI Confidence interval; HR Hazard ratio; MBC Metastatic breast cancer; SUVmax Maximum standard uptake value
^* Indicates statistically significant differences (P < 0.05); N/A: Analysis not performed as univariate analysis not significant

ISSN: 1465-542X