Survival benefit of thermal ablation combined with chemotherapy for the treatment of stage IV nonsmall cell lung cancer: a propensity-matched analysis

Figures & data

Table 1. Baseline characteristics in the unmatched cohort and the matched cohort, n (%).

Characteristics	Unmatched cohort				Matched cohort
	Total	Chemotherapy (N = 524,22)	Thermal ablation +  chemotherapy (N = 152)	p Value	Chemotherapy (N = 445)	Thermal ablation +  chemotherapy (N = 150)	p Value
Age (years)				0.003			0.651
≤70	34,796 (66.18)	34,678 (66.15)	118 (77.63)		336 (75.51)	116 (77.33)
>70	17,778 (33.82)	17,744 (33.85)	34 (22.37)		109 (24.49)	34 (22.67)
Sex				0.635			0.816
Female	23,833 (45.33)	23,767 (45.34)	66 (43.42)		188 (42.25)	65 (43.33)
Male	28,741 (54.67)	28,655 (54.66)	86 (56.58)		257 (57.75)	85 (56.67)
Race				0.190			0.832
White	40,932 (77.86)	40,808 (77.85)	124 (81.58)		362 (81.35)	122 (81.33)
Black	6587 (12.53)	6567 (12.53)	20 (13.16)		64 (14.38)	20 (13.33)
Others	5055 (9.62)	5047 (9.63)	8 (5.26)		19 (4.27)	8 (5.33)
Marital status				0.602			0.915
Married	30,164 (57.37)	30,070 (57.36)	94 (61.84)		276 (62.02)	92 (61.33)
Not married	7325 (13.93)	7309 (13.94)	16 (10.53)		47 (10.56)	16 (10.67)
Separated	13294 (25.29)	13257 (25.29)	37 (24.34)		102 (22.92)	37 (24.67)
Unknown	1791 (3.41)	1786 (3.41)	5 (3.29)		20 (4.49)	5 (3.33)
Laterality				0.067			0.948
Left	21,470 (40.84)	21,419 (40.86)	51 (33.55)		150 (33.71)	51 (34.00)
Right	31,104 (59.16)	31,003 (59.14)	101 (66.45)		295 (66.29)	99 (66.00)
Location				<0.001			0.986
Lung lobe	46,428 (88.31)	46,321 (88.36)	107 (70.39)		321 (72.13)	107 (71.33)
Main bronchus	2351 (4.47)	2315 (4.42)	36 (23.68)		100 (22.47)	34 (22.67)
Overlapping lesion of lung	500 (0.95)	497 (0.95)	3 (1.97)		7 (1.57)	3 (2.00)
Lung, NOS	3295 (6.27)	3289 (6.27)	6 (3.95)		17 (3.82)	6 (4.00)
Grade				<0.001			0.964
I/II	7440 (14.15)	7416 (14.15)	24 (15.79)		73 (16.40)	24 (16.00)
III/IV	15,089 (28.70)	15,017 (28.65)	72 (47.37)		202 (45.39)	70 (46.67)
Unknown	30,045 (57.15)	29,989 (57.21)	56 (36.84)		170 (38.20)	56 (37.33)
WHO classification				<0.001			0.799
Adenocarcinoma	31,020 (59.00)	30,967 (59.07)	53 (34.87)		177 (39.78)	53 (35.33)
Squamous cell carcinoma	10,280 (19.55)	10,212 (19.48)	68 (44.74)		185 (41.57)	66 (44.00)
Large cell lung cancer	1470 (2.80)	1462 (2.79)	8 (5.26)		23 (5.17)	8 (5.33)
Others	9804 (18.65)	9781 (18.66)	23 (15.13)		60 (13.48)	23 (15.33)
Tumor size				0.103			0.722
0 ∼ 3.0 cm	15,147 (28.81)	15,116 (28.84)	31 (20.39)		100 (22.47)	31 (20.67)
3.1–5.0 cm	17,087 (32.50)	17,035 (32.50)	52 (34.21)		133 (29.89)	52 (34.67)
5.1–7.0 cm	11,139 (21.19)	11,104 (21.18)	35 (23.03)		113 (25.39)	34 (22.67)
>7cm	9201 (17.50)	9167 (17.49)	34 (22.37)		99 (22.25)	33 (22.00)
Nodal stage				0.950			0.680
N0	10,437 (19.85)	10,408 (19.85)	29 (19.08)		72 (16.18)	29 (19.33)
N1	4315 (8.21)	4301 (8.20)	14 (9.21)		35 (7.87)	14 (9.33)
N2	25,437 (48.38)	25,362 (48.38)	75 (49.34)		225 (50.56)	74 (49.33)
N3	12,385 (23.56)	12,351 (23.56)	34 (22.37)		113 (25.39)	33 (22.00)
Radiotherapy				<0.001			0.981
No	22,535 (42.86)	22,491 (42.90)	44 (28.95)		131 (29.44)	44 (29.33)
Yes	30,039 (57.14)	29,931 (57.10)	108 (71.05)		314 (70.56)	106 (70.67)

NOS: not otherwise specified.

Figure 1. Kaplan–Meier curves of stage-IV NSCLC. (A) thermal ablation plus chemotherapy versus chemotherapy for OS before PSM; (B) thermal ablation plus chemotherapy versus chemotherapy for LCSS before PSM; (C) thermal ablation plus chemotherapy versus chemotherapy for OS after PSM; (D) thermal ablation plus chemotherapy versus chemotherapy for LCSS after PSM. NSCLC: nonsmall cell lung cancer; OS: overall survival; LCSS: lung cancer-specific survival; PSM: propensity score matching.

Figure 2. Kaplan–Meier curves of stage-IV NSCLC. A: thermal ablation plus chemotherapy versus chemotherapy for OS of patients aged <70 years before PSM; B: thermal ablation plus chemotherapy versus chemotherapy for LCSS of patients aged <70 years before PSM; C: thermal ablation plus chemotherapy versus chemotherapy for OS of patients aged ?70 years after PSM; D: thermal ablation plus chemotherapy vs. chemotherapy for LCSS of patients aged ?70 years after PSM. NSCLC: nonsmall cell lung cancer, OS: overall survival, LCSS: lung cancer-specific survival, PSM: propensity score matching.

Figure 3. Kaplan–Meier curves of stage-IV NSCLC. (A) thermal ablation plus chemotherapy versus chemotherapy for OS of patients with tumor size 3 cm before PSM; (B) thermal ablation plus chemotherapy versus chemotherapy for LCSS of patients with tumor size 3 cm before PSM; (C) thermal ablation plus chemotherapy versus chemotherapy for OS of patients with tumor sizes of 3.1–5.0 cm after PSM; (D) thermal ablation plus chemotherapy versus chemotherapy for LCSS of patients with tumor sizes of 3.1–5.0 cm after PSM. NSCLC: nonsmall cell lung cancer; OS: overall survival; LCSS: lung cancer-specific survival; PSM: propensity score matching.

Figure 4. Kaplan–Meier curves of stage-IV NSCLC. (A) thermal ablation plus chemotherapy versus chemotherapy for OS of patients with tumor sizes of 5.1–7.0 cm before PSM; (B) thermal ablation plus chemotherapy versus chemotherapy for LCSS of patients with tumor sizes of 5.1–7.0 cm before PSM; (C) thermal ablation plus chemotherapy versus chemotherapy for OS of patients with tumor size >7.0 cm after PSM; (D) thermal ablation plus chemotherapy versus chemotherapy for LCSS of patients with tumor size >7.0 cm after PSM. NSCLC: nonsmall cell lung cancer; OS: overall survival; LCSS: lung cancer-specific survival; PSM: propensity score matching.

Table 2. Univariable and multivariable analysis for OS in the whole cohort.

Characteristics	Univariable		Multivariable
	HR (95%CI)	p Value	HR (95%CI)	p Value
Age (years)
≤70	1.00		1.00
>70	1.15 (1.12–1.17)	<0.001	1.18 (1.15–1.20)	<0.001
Sex
Female	1.00		1.00
Male	1.24 (1.22–1.27)	<0.001	1.23 (1.20–1.25)	<0.001
Race
White	1.00		1.00
Black	0.96 (0.93–0.99)	0.004	0.94 (0.92–0.97)	<0.001
Others	0.69 (0.67–0.72)	<0.001	0.71 (0.69–0.74)	<0.001
Marital status
Married	1.00		1.00
Not married	1.04 (1.01–1.07)	<0.001	1.06 (1.03–1.09)	<0.001
Separated	1.07 (1.05–1.10)	<0.001	1.10 (1.07–1.12)	<0.001
Unknown	0.97 (0.92–1.02)	0.290	0.99 (0.94–1.04)	0.625
Laterality
Left	1.00		1.00
Right	1.02 (1.00–1.04)	0.018	1.02 (1.00–1.04)	0.064
Location
Lung lobe	1.00		1.00
Main bronchus	1.18 (1.13–1.23)	<0.001	1.13 (1.08–1.18)	<0.001
Overlapping lesion of lung	1.17 (1.07–1.29)	0.001	1.17 (1.06–1.28)	<0.001
Lung, NOS	1.03 (0.99–1.07)	0.186	1.05 (1.01–1.09)	0.017
Grade
I/II	1.00		1.00
III/IV	1.29 (1.26–1.33)	<0.001	1.20 (1.16–1.23)	<0.001
Unknown	1.15 (1.12–1.18)	<0.001	1.12 (1.09–1.15)	<0.001
WHO classification
Adenocarcinoma	1.00		1.00
Squamous cell carcinoma	1.31 (1.28–1.34)	<0.001	1.17 (1.14–1.20)	<0.001
Large cell lung cancer	1.44 (1.36–1.52)	<0.001	1.32 (1.25–1.40)	<0.001
Others	1.32 (1.29–1.35)	<0.001	1.24 (1.21–1.27)	<0.001
Tumor size
0–3.0 cm	1.00		1.00
3.1–5.0 cm	1.07 (1.05–1.10)	<0.001	1.05 (1.03–1.08)	<0.001
5.1–7.0 cm	1.22 (1.18–1.25)	<0.001	1.15 (1.12–1.18)	<0.001
>7 cm	1.37 (1.33–1.41)	<0.001	1.28 (1.24–1.31)	<0.001
Nodal stage
N0	1.00		1.00
N1	1.11 (1.06–1.15)	<0.001	1.10 (1.06–1.14)	<0.001
N2	1.23 (1.20–1.26)	<0.001	1.21 (1.18–1.24)	<0.001
N3	1.22 (1.19–1.26)	<0.001	1.23 (1.20–1.27)	<0.001
Radiotherapy
No	1.00		1.00
Yes	1.11 (1.09–1.13)	<0.001	1.09 (1.07–1.11)	<0.001
Therapy
Chemotherapy	1.00		1.00
Thermal ablation + chemotherapy	0.81 (0.68–0.97)	0.018	0.70 (0.59–0.84)	<0.001

OS: overall survival; HR: hazard ratio; CI: confidence interval; NOS: not otherwise specified.

Table 3. Univariable and multivariable analysis for LCSS in the whole cohort.

Characteristics	Univariable		Multivariable
	HR (95%CI)	p Value	HR (95%CI)	p Value
Age (years)
≤70	1.00		1.00
>70	1.12 (1.10–1.15)	<0.001	1.15 (1.13–1.18)	<0.001
Sex
Female	1.00		1.00
Male	1.24 (1.21–1.26)	<0.001	1.22 (1.19–1.24)	<0.001
Race
White	1.00		1.00
Black	0.95 (0.92–0.98)	<0.001	0.93 (0.91–0.96)	<0.001
Others	0.68 (0.66–0.71)	<0.001	0.70 (0.68–0.73)	<0.001
Marital status
Married	1.00		1.00
Not married	1.03 (1.00–1.05)	0.089	1.04 (1.01–1.07)	0.006
Separated	1.07 (1.04–1.09)	<0.001	1.09 (1.07–1.12)	<0.001
Unknown	0.96 (0.91–1.01)	0.135	0.97 (0.92–1.03)	0.335
Laterality
Left	1.00		1.00
Right	1.02 (1.00–1.04)	0.015	1.02 (1.00–1.04)	0.069
Location
Lung lobe	1.00		1.00
Main bronchus	1.17 (1.12–1.23)	<0.001	1.12 (1.07–1.17)	<0.001
Overlapping lesion of lung	1.19 (1.08–1.30)	<0.001	1.18 (1.08–1.30)	<0.001
Lung, NOS	1.03 (0.99–1.07)	0.196	1.05 (1.01–1.09)	0.019
Grade
I/II	1.00		1.00
III/IV	1.30 (1.26–1.35)	<0.001	1.20 (1.17–1.24)	<0.001
Unknown	1.16 (1.13–1.19)	<0.001	1.13 (1.10–1.17)	<0.001
WHO classification
Adenocarcinoma	1.00		1.00
Squamous cell carcinoma	1.30 (1.27–1.33)	<0.001	1.16 (1.13–1.19)	<0.001
Large cell lung cancer	1.44 (1.37–1.53)	<0.001	1.32 (1.25–1.40)	<0.001
Others	1.33 (1.29–1.36)	<0.001	1.24 (1.21–1.27)	<0.001
Tumor size
0–3.0 cm	1.00		1.00
3.1–5.0 cm	1.08 (1.05–1.10)	<0.001	1.06 (1.03–1.09)	<0.001
5.1–7.0 cm	1.22 (1.19–1.25)	<0.001	1.15 (1.12–1.19)	<0.001
>7 cm	1.38 (1.34–1.42)	<0.001	1.29 (1.25–1.32)	<0.001
Nodal stage
N0	1.00		1.00
N1	1.12 (1.07–1.16)	<0.001	1.11 (1.07–1.15)	<0.001
N2	1.24 (1.21–1.27)	<0.001	1.22 (1.19–1.25)	<0.001
N3	1.23 (1.20–1.27)	<0.001	1.24 (1.20–1.27)	<0.001
Radiotherapy
No	1.00		1.00
Yes	1.12 (1.09–1.14)	<0.001	1.10 (1.08–1.12)	<0.001
Therapy
Chemotherapy	1.00		1.00
Thermal ablation + chemotherapy	0.80 (0.67–0.96)	0.017	0.70 (0.58–0.84)	<0.001

LCSS: lung cancer–specific survival; HR: hazard ratio; CI: confidence interval; NOS: not otherwise specified.

Data availability statement

All the data that support the results of the current study are publicly available in the SEER database (https://seer.cancer.gov/).