Comparison between surgery and thermal ablation for adrenal metastases: a retrospective study

Figures & data

Figure 1. Flowchart of patients enrolled.

Table 1. Baseline characteristics of ablation and surgery group.

	Ablation group	Surgery group	p-value
Number	57	76
Age			0.925
Mean ± SD (range)	58.03 ± 12.76 (34–89)	58.00 ± 10.65 (22–80)
Median	60	58
<65 years	41 (71.9%)	55 (72.4%)	0.955
≥65 years	16 (28.1%)	21 (27.6%)
Sex			0.442
Male	48 (84.2%)	60 (78.9%)
Female	9 (15.8%)	16 (21.1%)
Size (mm)
Mean ± SD (range)	36.60 ± 17.24 (90–940)	33.33 ± 19.90 (90–1010)	0.99
<3cm	25 (43.9%)	37 (48.7%)	0.581
≥3cm	32 (56.1%)	39 (51.3%)
Histology			<0.001
HCC	30 (52.6%)	14 (18.4%)
NSCLC	17 (29.8%)	33 (43.4%)
other	10 (17.5%)	29 (38.2%)
Distribution			0.413
Unilateral	51 (89.5%)	71 (93.4%)
Bilateral	6 (10.5%)	5 (6.6%)
Other distant metastasis			<0.001
Yes	39 (68.4%)	19 (25%)
No	18 (31.6%)	57 (75%)
Timing of metastasis			0.263
Synchronous	9 (15.8%)	18 (17.1%)
Metachronous	48 (84.2%)	58 (82.9%)
Oligometastasis			<0.001
Yes	25 (43.9%)	66 (86.8%)
No	32 (56.1%)	10 (13.2%)
Systematic chemotherapy			0.566
Yes	38 (66.7%)	47 (61.8%)
No	19 (33.3%)	29 (38.2%)

Note: Oligometastases in reference to a hypothesized intermediate state between loco-regional and disseminated metastatic disease, usually defined as the existence of one to five isolated macroscopic metastases. Synchronous metastasis is defined as a DFI (disease-free interval) less than 6 months, and metachronous metastasis, as a DFI more than 6 months.

Figure 2. 56-year-old male patient with lung adenocarcinoma presented bilateral adrenal metastases after resection of the primary tumor (a) CT-guided microwave ablation was performed on the adrenal metastases in lateral position (b) and prone position (c) respectively. The adrenal metastases showed complete necrosis 6 months after ablation (d).

Table 2. Univariate and multivariate analysis of the relative risk of local progression-free survival.

Characteristic	Number	LPFS
		Univariable	Multivariate
		p-values	p-values	HR (95CI%)
Age		0.097	0.209	0.573 (0.24–1.367)
<65 years	96
≥65 years	37
Sex		0.205
Male	108
Female	25
Size(mm)		0.027	0.031	2.186 (1.074–4.449)
<3cm	62
≥3cm	71
Treatment method		0.946
SR	76
Ablation	57
Histology		0.772
HCC	44
NSCLC	50
other	39
Distribution		0.424
Unilateral	122
Bilateral	11
Distant metastases		0.631
Present	58
Absent	75
Timing of metastases		0.318
Synchronous	27
Metachronous	106
Oligometastases		0.763
Yes	91
No	42
Systematic chemotherapy		0.763
Yes	85
No	48

Note: CI: confidence interval; HR: hazard ratio; OS: overall survival; LPFS: local progression-free survival.

Figure 3. Recurrence after resection of the adrenal metastases. Four months after radical resection of right-lower lung cancer(pT2aN0M0), the 59-year-old male patient was founded with a right adrenal metastasis (size: 40mm × 29mm). (a) The primary lung tumor. (b) No tumor nodule was found in the right adrenal gland before pulmonary tumor resection. (c, d) The right adrenal metastasis. According to suggestion of the MDT, the patient received the right adrenal tumor resection (e). However, right adrenal metastasis (size: 29mm × 22mm) recurred 3 months after adrenal resection (f).

Table 3. Adverse events in ablation group and surgery group.

	Clavien–Dindo	Ablation (n = 73)	SR (n = 76)	p-value
	Classification
Major complication		3 (4.1%)	11 (14.5%)	0.03
Pneumothorax	III-a	1	0
Shock	II	1	0
Hemorrhage	II	1	8
Pneumonia	II	0	1
Wound infection	II	0	1
Adrenal insufficiency	II	0	1
Minor complication		14 (19.2%)	1 (1.3%)	<0.001
Hypertension crisis	I	7	1
Hemothorax	I	1	0
Hemorrhage	I	4	0
Self-limited Pneumothorax	I	2	0
Side effect		38 (52.1%)	61 (80.3%)	<0.001
Fever	I	8	14
Pain
Mild	I	3	33
Moderate	I	17	10
Severe	I	4	1
Vomit	I	6	3

Figure 4. Kaplan–Meier curve of local progression-free survival between patients with thermal ablation versus surgery.