Tumour seeding after percutaneous cryoablation for hepatocellular carcinoma

Table 1 Baseline characteristics of patients n (%)

Baseline characteristics	Value
Age (yr)1	55.9 ± 9.2
Sex
Male	1176 (81.9)
Female	260 (18.1)
Aetiology
HBs-Ag positive only	1229 (85.6)
HCV-Ab positive only	168 (11.7)
Both positive	19 (1.3)
Both negative	20 (1.4)
Child-Pugh score
Class A	874 (60.9)
Class B	562 (39.1)
Tumour size (cm)
≤ 3	411 (28.6)
3-5	656 (45.7)
≥ 5	369 (25.7)
Tumour number
Single	1213 (84.5)
2-3	223 (15.5)
Tumour location
Subcapsular	484 (33.7)
No subcapsular	952 (66.3)
Route of needle insertion
Direct subcapsular insertion	213 (14.8)
Deep	1223 (85.2)
BCLC staging
Stage A	787 (54.8)
Stage B	453 (31.5)
Stage C	196 (13.7)
Completed ablation
Yes	1168 (81.3)
No	268 (18.7)
Tumour differentiation2
Well or moderate	490 (66.6)
Poorly	246 (33.4)
Biopsy performed prior to cryoablation2	736 (51.3)
Number of sessions
Single	336 (23.4)
2	743 (51.7)
> 2	357 (24.9)
AFP (ng/mL)1	575 ± 2039

¹Values are expressed as mean ± SD, n = 1436;

²Of 736 cases in which biopsy was performed. HBs-Ag: Hepatitis B surface antigen; HCV-Ab: Hepatitis C virus antibody; BCLC: The Barcelona Clinic Liver Cancer classification; AFP: Alpha-fetoprotein.

Table 2 Characteristics of the 11 hepatocellular carcinoma patients who had tumour seeding after cryoablation

Case No.	1	2	3	4	5	6	7	8	9	10	11
Age (yr)	66	51	47	51	65	43	49	61	58	58	72
Sex	M	F	M	M	F	M	M	M	M	F	M
Child-Pugh class	A	A	A	A	B	A	A	B	A	A	B
BCLC Stage	A	B	B	B	B	C	A	B	A	A	B
AFP (ng/mL)	7	9	3550	368	8589	16	75	33	23	48	294
No. of tumours	1	1	1	1	1	1	1	3	1	2	1
Tumour size (cm)	6	3	5.4	6	3.2	8	2.4	4.8	2.6	2	5.6
No. of sessions	2	1	4	3	1	3	1	2	1	4	2
No. of needle insertions	4	2	6	4	2	6	1	3	1	4	3
Completed ablation	Yes	Yes	No	No	Yes	No	Yes	Yes	Yes	Yes	Yes
Biopsy	No	Yes	Yes	Yes	Yes	No	No	No	No	Yes	Yes
Tumour differentiation
Primary HCC	-	Poor	Mod	Mod	Poor	-	-	-	-	Well	Poor
Seeding HCC	Mod	Poor	Mod	Mod	-	Mod	Mod	Mod	Mod	Well	-
Subcapsular location	Yes	No	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
Direct subcapsular insertion	Yes	No	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	No
Seeding location	Ip	Ip	Sf	Ip	Pleura	Ip and Im	Ip	Ip	Ip	Ip	Pc
Seeding time (mo)	24	2	5	5	1	6	12	7	12	18	1
Overall survival (mo)	36	25	9	19	18	12	18	26	36	60	5
Prognosis	Died	Alive	Died	Died	Died	Alive	Alive	Died	Alive	Alive	Alive

M: Male; F: Female; Ip: Intraperitoneal; Sf: Subcutaneous fat; Im: Intercostal muscle; Pc: Peritoneal cavity; HCC: Hepatocellular carcinoma; BCLC: The Barcelona Clinic Liver Cancer classification; AFP: Alpha-fetoprotein; Mod: Moderate.

Table 3 Characteristics of patients with and without tumour seeding

Variable	Seeding was identified(n = 11)	Seeding was not identified (n = 1425)	P value
Age (yr)1	56.5 ± 9.0	55.5 ± 9.3	0.8970
Gender (male/female)	8/3	1168/257	0.6895
HBs-Ag positive only	10	1219	0.9412
HCV-Ab positive only	1	167	1.0000
Both positive	0	19	1.0000
Both negative	0	20	1.0000
Child-Pugh class (A/B)	8/3	866/559	0.6176
Tumour size (cm)1	4.5 ± 1.9	4.6 ± 3.0	0.8800
Number of tumours1	1.3 ± 0.6	1.3 ± 0.7	0.9520
Number of sessions1	2.2 ± 1.2	2.3 ± 1.1	0.8764
Number of needle insertions1	3.3 ± 1.7	3.8 ± 1.1	0.3430
Direct subcapsular insertion	8	205	0.0043
Subcapsular location	8	476	0.0152
Biopsy performed2	6	730	0.8264
Poorly differentiated tumour	3	243	0.6674
BCLC stage (A/B/C)	4/6/1	783/447/195	0.2869
Completed ablation (yes/no)	8/3	1161/264	0.7235
AFP (ng/mL)1	1182.9 ± 2668.6	577.0 ± 2038.1	0.3270

¹Values are expressed as mean ± SD;

²Of 736 cases in which biopsy was performed. HBs-Ag: Hepatitis B surface antigen; HCV-Ab: Hepatitis C virus antibody; BCLC: The Barcelona Clinic Liver Cancer classification; AFP: Alpha-fetoprotein.