Table 4.

Effect of Delay From Recurrence to Initiation of Salvage Radiotherapy on Multivariable Proportional Hazards Model for Risk of Prostate Cancer–Specific Mortality, 1982–2004^a

	Delay <2 y (n = 552); (105 Deaths)b			Delay ≥2 y (n = 480); (100 Deaths)c
Variables	HR (95% CI)		P Value	HR (95% CI)		P Value
Time from surgery to recurrence, y	0.87 (0.79–0.96)d		.006	0.86 (0.77–0.96)d		.006
Calendar year of surgery	0.89 (0.85–0.94)d		<.001	0.93 (0.88–0.98)d		.006
Postoperative Gleason score
≤7	1 [Reference]		<.001	1 [Reference]		<.001
8–10	2.58 (1.73–3.85)			2.67 (1.77–4.03)
Salvage treatment			<.001e			.87f
PSA doubling time <6 mo
No salvage therapy	1 [Reference]			1 [Reference]
Radiotherapy (with or without hormonal therapy)	0.14 (0.06–0.34)			0.80 (0.11–5.93)
PSA doubling time ≥6 mo
No salvage therapy	1 [Reference]			1 [Reference]
Radiotherapy (with or without hormonal therapy)	0.72 (0.36–1.46)			0.84 (0.40–1.74)

Abbreviations: CI, confidence interval; HR, hazard ratio; PSA, prostate-specific antigen.

^aSurvival time measured from date of recurrence.

^bA total of 103 received salvage radiotherapy alone and 52 received salvage radiotherapy plus hormonal therapy. Analysis included the entire cohort of 397 men who did not receive salvage therapy.

^cA total of 57 received salvage radiotherapy alone and 26 received salvage radiotherapy plus hormonal therapy. Analysis included the entire cohort of 397 men who did not receive salvage therapy.

^dThe HR is per 1-year increase.

^eP value represents the likelihood ratio test for adding salvage treatment (1 variable) and 1 interaction term to the model: likelihood ratio ${\chi }_2^2=31.2$.

^fP value represents the likelihood ratio test for adding salvage treatment (1 variable) and 1 interaction term to the model: likelihood ratio ${\chi }_2^2=0.28$.