Hot dots – which nodes should be removed in sentinel lymph node biopsy for melanoma?

Figures & data

Figure 1. Order of the most radioactive or hottest positive SLN in the study population of 175 patients according to radiotracer uptake. Number one represents 137 patients with a positive hottest SLN. Numbers two and three represent patients with a negative hottest SLN, who presented with a metastasis in the second or third hottest SLN, respectively. In eight cases, indicated with >3, the three hottest SLNs were negative and a less radioactive node harboured metastasis. SLN: sentinel lymph node.

Table 1. Clinicopathologic characteristics of all 175 patients and 160 patients with more than one SLN removed stratified by the status of the hottest SLN, i.e. SLN with highest radiotracer uptake.

	All patients	Patients with >1 SLNs removed (N = 160)
		Hottest SLN+	Hottest SLN-	p-value^(*
N	175	122	38
Age (y)
Median (range)	60 (14–90)	60 (14–89)	60 (23–85)	0.526
Gender
Female (%)	67 (38)	50 (41)	12 (32)	0.299
Male (%)	108 (62)	72 (59)	26 (68)
Location of primary tumour N (%)
Head&Neck	20 (11.4)	14 (12)	4 (11)	0.082
Trunk	79 (45.2)	52 (43)	20 (52)
Upper limb	28 (16)	16 (13)	9 (24)
Lower limb	48 (27.4)	40 (32)	5 (13)
Breslow thickness (mm)
Mean	3.3	3.6	2.4	0.011
Median (range)	2.7 (0.80–21.0)	3.0 (0.80–21)	2.0 (0.95–6.0)
T Category N (%)
T1 ≤ 1 mm	12 (7)	8 (7)	3 (8)
T2 > 1–2 mm	55 (31)	35 (28)	17 (45)
T3 > 2–4 mm	68 (39)	49 (40)	13 (34)
T4 > 4 mm	40 (23)	30 (25)	5 (13)
Ulceration N (%)
Yes	43 (25)	31 (25)	9 (24)	0.595
No	128 (73)	88 (72)	29 (76)
Unknown	4 (2)	3 (3)	-
Number of basins
1	133	91	27	0.665
2	38	29	9
3	4	2	2
Number of SLNs
Mean	4.5	4.7	5.2	0.292
Median (range)	4 (1–15)	4 (2–15)	5 (2–12)
Number of positive SLNs
Mean	1.5	1.7	1.2	<0.001
Median (range)	1 (1–7)	1 (1–7)	1 (1–2)
Mean diameter of the largest tumour deposit in SLN (mm)	2.2	2.5	1.1	<0.001
CLND performed N (%)	151 (86%)	104 (85%)	33 (87%)	0.599
Additional metastatic nodes in CLND N (% of CLNDs)	18 (12)	14 (13)	2 (6)	0.379

SLN: sentinel lymph node; CLND: completion lymph node dissection.

^*)p-values refer to the comparison between 122 patients with a positive hottest SLN and 38 patients with a negative hottest SLN.

Figure 2. Distribution of 175 patients according to the radiotracer uptake of the most radioactive positive SLN compared with the hottest SLN. The column of 100% represents 137 patients with a positive hottest SLN. SLN: sentinel lymph node.

Table 2. SNB according to various retrospectively applied SLN criteria based on which nodes are removed from a lymph node basin.

Definition of SLN	Number of SLNs	Positive SLNs	Positive nodes missed (%)	Number of patients with a change in N category ^(*	Number of under-staged patients ^(*
All hot and blue nodes	783	270	–	–	–
All hot nodes	782	270	–	–	–
>10% and blue	588	256	14 (5.2)	8	2
>10%	560	250	20 (7.4)	12	6
>50%	317	196	74 (27)	51	17
Three hottest	512	239	31 (11)	19	8
Two hottest	390	213	57 (21)	33	14
Hottest only	220	156	114 (42)	78	34

^*) According to the 8th edition of AJCC staging manual. SNB: sentinel lymph node biopsy; SLN: sentinel lymph node.

Data availability statement

The participants of this study did not give written consent for their data to be shared publicly, so due to the sensitive nature of the research supporting data is not available.