Table 2.

Log‐rank test results

Variable	Patients (n = 96)	P‐value
		OS	PFS	LC
Age, years
<60	55
≥60	41	0.167	0.455	0.380
Sex
M	51
F	45	0.606	0.455	0.041a
PS
0–1	89
2–3	7	<0.001a	<0.001a	0.066
Histological subtype
CH	72
Other	24	0.773	0.194	0.169
Tumor location
SB	68
Spine	28	0.524	0.019a	0.176
Tumor status
Primary	73
Recurrent	23	0.393	0.077	0.067
Surgery
Pre‐PBT	68
Post‐PBT/none	28	0.241	0.537	0.971
Chemotherapy
Pre‐PBT	4
Post‐PBT/none	92	0.065	0.117	0.880
PTV, mL
≤70	48
>70	48	0.056	0.026a	0.154
Radiotherapy
PBT alone	93
PBT + photon radiotherapy	3	0.280	0.145	0.193
BED10, Gy (RBE)
≤85	49
>85	47	0.250	0.240	0.637

^a P < 0.05.

BED₁₀, biologically effective dose, alpha/beta = 10 Gy; CH, chordoma; F, female; LC, local control; M, male; OS, overall survival; PBT, proton beam therapy; PFS, progression‐free survival; PS, performance status; PTV, planning target volume; RBE, relative biological effectiveness; SB, skull base.