Hypofractionated Proton Boost Combined with External Beam Radiotherapy for Treatment of Localized Prostate Cancer

Table 6

Cox regression model—GI grade 2 or higher^*.

	Univariate analysis			Multivariate analysis
	HR	(95% CI)	𝑃	HR	(95% CI)	𝑃
Age at diagnosis, continuous	1.00	(0.92–1.09)	0.984	0.99	(0.90–1.08)	0.743
Risk group
Low risk	1.00	(ref.)	—	1.00	(ref.)	—
Intermediate risk	1.12	(0.37–3.43)	0.842	1.17	(0.37–3.71)	0.791
High risk	1.22	(0.41–3.65)	0.720	1.27	(0.42–3.85)	0.673
Smoker
No	1.00	(ref.)	—	1.00	(ref.)	—
Yes	0.73	(0.22–2.46)	0.610	0.57	(0.16–2.05)	0.388
Diabetic
No	1.00	(ref.)	—	1.00	(ref.)	—
Yes	3.23	(1.26–8.33)	0.014	3.51	(1.35–9.13)	0.010
Rectal rod
No	1.00	(ref.)	—	1.00	(ref.)	—
Yes	1.41	(0.58–3.43)	0.453	1.36	(0.56–3.33)	0.499
log-PTV proton volume, continuous	1.68	(0.46–6.17)	0.433	1.94	(0.48–7.89)	0.355

^*Only including patients with GI grade 0 at baseline and not missing information on smoking, diabetes, rectal rod, and PTV volume (𝑁=236).