Table 5.

Test for an Interaction Between the Ki-67 and MDM2 Combination and Treatment Arm

Covariate by End Point	Analysis
	HR	95% CI	P*
DM
Ki-67 and MDM2
≤ 11.3% and ≤ 184	RL	—	—
≤ 11.3% and > 184	0.79	0.22 to 2.76	.71
> 11.3% and ≤ 184	4.66	2.23 to 9.75	< .0001
> 11.3% and > 184	5.34	2.25 to 12.69	.0002
Treatment arm
STAD + RT	2.63	1.34 to 5.16	.005
Group 1 and treatment interaction	2.44	0.57 to 10.41	.23
Group 2 and treatment interaction	0.43	0.16 to 1.20	0.11
Group 3 and treatment interaction	0.90	0.31 to 2.66	0.85
CSM
Ki-67 and MDM2
≤ 11.3% and ≤ 184	RL	—	—
≤ 11.3% and > 184	0.45	0.10 to 1.93	.28
> 11.3% and ≤ 184	2.38	1.06 to 5.37	.04
> 11.3% and > 184	3.92	1.67 to 9.20	.002
Treatment arm
STAD + RT	1.62	0.82 to 3.18	.16
Group 1 and treatment interaction	4.57	0.87 to 24.01	.07
Group 2 and treatment interaction	1.10	0.36 to 3.31	.87
Group 3 and treatment interaction	1.00	0.32 to 3.15	1.00
OM
Ki-67 and MDM2
≤ 11.3% and ≤ 184	RL	—	—
≤ 11.3% and > 184	1.35	0.85 to 2.16	.21
> 11.3% and ≤ 184	1.52	1.02 to 2.25	.04
> 11.3% and > 184	2.41	1.45 to 4.01	.0007
Treatment arm
STAD + RT	1.18	0.85 to 1.63	.32
Group 1 and treatment interaction	1.05	0.53 to 2.07	.90
Group 2 and treatment interaction	0.96	0.50 to 1.85	.91
Group 3 and treatment interaction	0.66	0.31 to 1.41	.28

^*P value is from χ² test with the Cox proportional hazards model.

Abbreviations: HR, hazard ratio; DM, distant metastasis; RL, reference; STAD, short-term androgen deprivation; RT, radiotherapy; CSM, cause-specific mortality; OM, overall mortality.