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

Table 1 Baseline patient characteristics, n (%)

Characteristics	Data
Sex
Male	75 (93.8)
Female	5 (6.2)
Age, year, median (range)	63 (44-75)
Length of primary focus, cm, median (range)	7 (2-17)
Tumor location
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
T1	2 (2.5)
T2	16 (20.0)
T3	54 (67.5)
T4	8 (10.0)
Clinical N stage
N0	3 (3.7)
N1	37 (46.3)
N2	21 (26.3)
N3	19 (23.7)
Clinical M stage
M0	69 (86.2)
M1	11 (13.8)
Radiotherapy regimens
Chemoradiotherapy	37(46.3)
Radiotherapy alone	43 (53.7)
Radiation dose
≤ 50 Gy	15 (18.8)
> 50 Gy	65 (81.2)
Induction chemotherapy regimen
Paclitaxel-based combination of platinum	78 (97.5)
Fluorouracil-based combination of platinum	2 (2.5)
Induction immunotherapy regimen
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)
Concurrent chemotherapy regimen
Paclitaxel-based combination of platinum	27 (88.8)
Single-agent albumin paclitaxel	2 (2.5)
Single-agent tegafur	7 (8.7)
Reasons for no surgery
Unresectable or medically inoperable	57 (71.3)
Refusal of surgery	23 (28.7)

T: Tumor; N: Node; M: Metastasis.

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.

Table 3 Multifactorial analysis of overall survival in 77 patients

Characteristics	HR	95%CI	P value
Therapeutic effectiveness of induction therapy
Partial response	1.000
Stable disease	2.113	1.113-4.013	0.022
PTV dose
≤ 50 Gy	1.000
> 50 Gy	0.620	0.300-1.284	0.198
Maintenance of immunotherapy
Yes	1.000
No	0.402	0.185-0.957	0.039

HR: Hazard ratio; CI: Confidence interval; OS: Overall survival; PTV: Planned tumor volume.