Proposed prognostic subgroups and facilitated clinical decision-making for additional locoregional radiotherapy in de novo metastatic nasopharyngeal carcinoma: a retrospective study based on recursive partitioning analysis

Table 1 Clinical characteristics

	Training cohort No. (%)	Validation cohort No. (%)	P
Total	264	298
Age (years)
< 47	130 (49.2)	148 (49.7)	0.920
≥ 47	134 (50.8)	150 (50.3)
Sex
Male	218 (82.6)	252 (84.6)	0.525
Female	46 (17.4)	46 (15.4)
Family history of NPC
No	245 (92.8)	277 (93.0)	0.945
Yes	19 (7.2)	21 (7.0)
Smoking history
No	157 (59.5)	191 (64.1)	0.260
Yes	107 (40.5)	107 (35.9)
Drinking history
No	239 (90.5)	278 (93.3)	0.229
Yes	25 (9.5)	20 (6.7)
Tumor stage*
T1-T2	42 (15.9)	31 (10.4)	0.053
T3-T4	222 (84.1)	267 (89.6)
Node stage*
N0-N1	49 (18.6)	42 (14.1)	0.151
N2-N3	215 (81.4)	256 (85.9)
Bone involvement
No	83 (31.4)	82 (27.5)	0.308
Yes	181 (68.6)	216 (72.5)
Lung involvement
No	200 (75.8)	224 (75.2)	0.871
Yes	64 (24.2)	74 (24.8)
Liver involvement
No	185 (70.1)	223 (74.8)	0.207
Yes	79 (29.9)	75 (25.2)
Distant lymph node involvement
No	220 (83.3)	230 (77.2)	0.068
Yes	44 (16.7)	68 (22.8)
Number of involved organs
Single	192 (72.7)	199 (66.8)	0.126
Multiple	72 (27.3)	99 (33.2)
Number of involved lesions
Single	67 (25.4)	63 (21.1)	0.234
Multiple	197 (74.6)	235 (78.9)
EBV-DNA status
EBV-DNA negative	24 (9.1)	17 (5.7)	0.123
EBV-DNA positive	240 (90.9)	281 (94.3)
Therapy regimens
PCT	131 (49.6)	112 (37.6)	0.004
PCT plus IMRT	133 (50.4)	186 (62.4)
Chemotherapy cycle
< 4	27 (10.2)	19 (6.4)	0.096
≥ 4	237 (89.8)	279 (93.6)
Radiotherapy dose of loco-regional
< 66 Gy	2 (1.5)	1 (0.5)	0.573
≥ 66 Gy	131 (98.5)	185 (99.5)
Pattern of Radiotherapy
LRRT alone	66 (49.6)	79 (42.5)	0.206
CCT plus LRRT	67 (50.4)	107 (57.5)

NPC nasopharyngeal carcinoma, PCT palliative chemotherapy, IMRT intensity-modulated radiotherapy, LRRT locoregional intensity-modulated radiotherapy, CCT concurrent chemotherapy, EBV Epstein–Barr virus, No. Number
^*According to the 8th TNM staging system

ISSN: 1748-717X