Safety and effectiveness of induction chemoimmunotherapy followed by definitive radiotherapy or concurrent chemoradiotherapy in esophageal squamous cell carcinoma

Table 2 Univariate analysis of progression-free survival and overall survival in 77 patients

Characteristics	Data, n (%)	PFS, χ2 value	PFS, P value	OS, χ2 value	OS, P value
Sex		0.296	0.604	0.198	0.657
Male	72 (93.5)
Female	5 (6.5)
Age, year		1.354	0.245	1.784	0.182
< 65	43 (55.8)
≥ 65	34 (44.2)
Tumor length		0.138	0.710	0.023	0.879
< 7 cm	37 (48.1)
≥ 7 cm	40 (51.9)
Tumor location		2.235	0.525	4.433	0.218
Cervical segment	1 (1.2)
Upper thoracic segment	13 (16.3)
Middle thoracic segment	36 (45.0)
Inferior thoracic segment	30 (37.5)
Clinical T stage		0.795	0.372	0.069	0.793
T1-2	17 (22.1)
T3-4	60 (77.9)
Clinical N stage		1.826	0.177	0.001	0.976
N0-1	39 (50.6)
N2-3	38 (49.4)
Clinical M stage		0.004	0.948	0.003	0.995
M0	66 (85.7)
M1	11 (14.3)
Induction immunotherapy regimen		5.558	0.475	4.851	0.563
Camrelizumab	45 (56.2)
Pembrolizumab	14 (17.5)
Sintilimab	10 (12.5)
Tislelizumab	5 (6.2)
Nivolumab	1 (1.3)
Toripalimab	1 (1.3)
Durvalumab	4 (5.0)
Therapeutic effectiveness of induction therapy		6.509	0.011	7.341	0.007
Partial response	36 (45.0)
Stable disease	41 (52.5)
Radiotherapy modalities		0.894	0.344	1.949	0.163
Radiotherapy	36 (46.8)
CCRT	41 (53.2)
PTV dose		1.733	0.188	4.223	0.040
≤ 50 Gy	13 (16.8)
> 50 Gy	64 (83.1)
Whether maintenance of immunotherapy		1.811	0.178	6.349	0.012
Yes	23 (29.9)
No	54 (70.1)

PFS: Progression-free survival; OS: Overall survival; T: Tumor; N: Node; M: Metastasis; CCRT: Concurrent chemoradiotherapy; PTV: Planned tumor volume.