Gene aberrations of RRM1 and RRM2B and outcome of advanced breast cancer after treatment with docetaxel with or without gemcitabine

Table 4 Cox univariate and multivariate analysis for time to progression and overall survival

Risk factor	n	Time to progression		P	Overall survival		P
Risk factor	n	HR	95% CI	P	HR	95% CI	P
Univariate analysis
*RRM1*
Normal	211	1.00	Referent		1.00	Referent
Aberration	40	0.86	(0.57-1.29)	0.46
Aberration 0–1.5 years*					0.59	(0.34-1.03)	0.06
Aberration 1.5-7.4 years*					1.67	(1.06-2.62)	0.03
*RRM2B*
Normal	217	1.00	Referent		1.00	Referent
Aberration	34	1.45	(0.94-2.25)	0.09	1.13	(0.78-1.64)	0.52
2R
Normal	184	1.00	Referent		1.00	Referent
Aberration	67	1.25	(0.92-1.69)	0.16
Aberration 0–1.5 years*					0.85	(0.56-1.28)	0.44
Aberration 1.5-7.4 years*					1.44	(0.96-2.17)	0.08
Multivariate analysis ^a
*RRM1* ^b
Normal	211	1.00	Referent		1.00	Referent
Aberration	40	0.66	(0.43-1.03)	0.07
Aberration 0–1.5 years*					0.56	(0.32-0.99)	0.05
Aberration 1.5-7.4 years*					1.72	(1.05-2.79)	0.03
*RRM2B* ^c
Normal	217	1.00	Referent		1.00	Referent
Aberration	34	1.41	(0.88-2.23)	0.15	1.00	(0.68-1.47)	1.00
2R
Normal	184	1.00	Referent		1.00	Referent
Aberration	67	0.92	(0.64-1.33)	0.66
Aberration 0–1.5 years*					0.80	(0.52-1.22)	0.30
Aberration 1.5-7.4 years*					1.36	(0.89-2.09)	0.16

Abbreviations: 2R aberration RRM1 and/or RRM2B aberrant, 2R normal RRM1 and RRM2B both normal, CI confidence interval, HR hazard ratio, RRM1 ribonucleotide reductase M1 subunit, RRM2B ribonucleotide reductase M2B subunit.
^aModels adjusted for the effects of PAM50 status, visceral disease, stage of disease, number of metastatic sites, and performance status. Models stratified for previous chemotherapy (none, n = 70; adjuvant, n = 86; locally advanced or metastatic, n = 95).
^bModel further adjusted for RRM2B.
^cModel further adjusted for RRM1.
*Time-dependant variable. If nothing is mentioned the maximum follow-up is 7.4 years after randomization for OS and 6.0 years after randomization for TTP.

ISSN: 1471-2407