Table 4.

Total body irradiation (TBI) dose in multivariate models of treatment with cyclophosphamide plus TBI as myeloablative conditioning regimen for allogeneic transplant using matched sibling and unrelated donor (2001–2013).

Outcome	n	Events	HR	Upper	Lower	P-value
Overall Survival
TBI dose						0.18
12 Gy	1732	1024	1.0
13–13.75 Gy	647	394	1.06	0.94	1.19	0.36
14 Gy	325	190	0.89	0.76	1.05	0.17
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.85	0.71	1.01	0.06
Disease-Free Survival
TBI dose						0.04
12 Gy	1727	1098	1.0
13–13.75 Gy	644	423	1.01	0.90	1.13	0.90
14 Gy	323	199	0.83	0.71	0.97	0.02
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.82	0.69	0.97	0.02
Non-Relapse Mortality
TBI dose						0.009a
12 Gy	1734	486	1.0
13–13.75 Gy	645	215	1.25	1.06	1.48	0.007
14 Gy	326	117	1.25	1.02	1.53	0.03
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.99	0.79	1.25	0.96
Relapse
TBI dose						0.008a
12 Gy	1737	618	1.0
13–13.75 Gy	646	209	0.92	0.78	1.08	0.29
14 Gy	323	84	0.69	0.55	0.88	0.002a
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.76	0.59	0.98	0.03
Acute GVHD Grade II-IV
TBI doseb	.	.	.	.	.	0.01
12 Gy	1724	739	1.0	.	.	.
13–13.75 Gy	640	313	1.15	1.00	1.31	0.05
14 Gy	326	137	0.85	0.71	1.03	0.09
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.74	0.61	0.91	0.004
Acute GVHD Grade III-IV
TBI dose						0.21
12 Gy	1728	329	1.0
13–13.75 Gy	641	148	1.18	0.97	1.44	0.10
14 Gy	324	66	0.96	0.73	1.27	0.79
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.82	0.61	1.10	0.18
Chronic GVHD
TBI dose (<=8 months)						0.0001c
12 Gy	1127	622	1.0
13–13.75 Gy	401	205	0.83	0.71	0.97	0.02
14 Gy	193	96	0.64	0.52	0.80	0.0001a
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.78	0.61	1.00	0.05
TBI dose (>8 months)						0.02
12 Gy	588	217	1.0
13–13.75 Gy	239	102	1.10	0.98	1.24	0.12
14 Gy	133	75	1.00	0.62	1.62	0.99
14 Gy vs. TBI 13–13.75 Gy (Ref.)			0.91	0.51	1.63	0.75
VOD/SOS
TBI dose						0.03
12 Gy	1737	88	1.0
13–13.75 Gy	648	36	1.16	0.78	1.71	0.46
14 Gy	322	30	1.77	1.17	2.69	0.007
14 Gy vs. TBI 13–13.75 Gy (Ref.)			1.53	0.94	2.49	0.08
IPS
TBI dose						0.80
12 Gy	1715	131	1.0
13–13.75 Gy	634	53	1.08	0.78	1.49	0.63
14 Gy	318	30	1.12	0.75	1.67	0.57
14 Gy vs. TBI 13–13.75 Gy (Ref.)			1.04	0.66	1.63	0.87

Abbreviations: GVHD, graft-versus-host disease; Gy, Gray; HR, hazard ratio; IPS, interstitial pneumonia syndrome; TBI, total body irradiation; VOD, veno-occlusive disease.

^aSignificant at p<0.01 level

^bAll patients received cyclophosphamide with TBI

^cSignificant at p < 0.01 level