Table 3. Univariate and multivariate Cox regression analysis for OS.

	Univariate		Multivariate
Variable	HR (95% CI)	p -Value	HR (95% CI)	p -Value
Age at diagnosis	0.99 (0.94–1.03)	0.69
Sex	1.94 (0.55–6.77)	0.29
Hyams grade, high vs. low	3.75 (0.96–14.6)	0.05	22.1 (2.2–218)	0.008
Kadish stage, A-B vs. C-D	0.22 (0.02–1.80)	0.16
Node status, positive vs. negative	11.7 (2.42–55.5)	0.002	14.7 (1.9–111)	0.01
Chemotherapy, yes vs. no	12.1 (1.87–76.9)	0.009	0.41 (0.04–3.87)	0.43
Radiation, yes vs. no	.03 (0.0–48.7)	0.35
Radiation, IORT vs. EBRT	.85 (0.18–3.9)	0.83
Radiation, ENI vs. primary only	.686 (0.2–4.3)	0.99
Surgery type, craniotomy vs. endoscopic	0.56 (0.12–2.59)	0.46
Diagnosis era, 1996–2010 vs. 2010–2017	0.94 (0.20–4.37)	0.94
Univariate and multivariate Cox regression of disease recurrence score
	Univariate		Multivariate
Variable	HR (95% CI)	p	HR (95% CI)	p -Value
Age at diagnosis	0.349 (0.07–1.6)	0.18
Sex	1.05 (0.32–3.48)	0.92
Hyams grade, high vs. low	12.5 (1.55–49.3)	0.01	17.0 (1.01–288.4)	0.049
Kadish stage, A-B vs. C-D	0.75 (0.23–2.5)	0.64
Node status, positive vs. negative	6.06 (1.33–27.7)	0.02	8.3 (0.57–10.5)	0.16
Chemotherapy, yes vs. no	0.44 (0.04–4.46)	0.48
Radiation, yes vs. no	0.37 (0.04–3.0)	0.36
Radiation, IORT vs. EBRT	1.6 (0.44–6.0)	0.46
Radiation, ENI vs. primary only	0.42 (0.04–3.9)	0.45
Surgery type, craniotomy vs. endoscopic	0.71 (0.19–2.6)	0.6
Diagnosis era, 1996–2010 vs. 2010–2017	1.8 (0.36–9.4)	0.44

Abbreviations: CI, confidence interval; EBRT, external beam radiation therapy; ENI, elective nodal radiation; HR, hazard ratio; IORT, intraoperative radiation therapy; OS, overall survival.