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Article

Sentinel Lymph Node Biopsy vs. Observation in Thin Melanoma: A Multicenter Propensity Score Matching Study

by
Antonio Tejera-Vaquerizo
1,2,*,†,
Aram Boada
3,†,
Simone Ribero
4,
Susana Puig
5,6,
Sabela Paradela
7,
David Moreno-Ramírez
8,
Javier Cañueto
9,
Blanca de Unamuno-Bustos
10,
Ana Brinca
11,
Miguel A. Descalzo-Gallego
12,
Simona Osella-Abate
13,
Paola Cassoni
13,
Sebastian Podlipnik
5,6,
Cristina Carrera
5,6,
Sergi Vidal-Sicart
14,
Ramón Pigem
5,6,
Agustí Toll
5,6,
Ramón Rull
15,
Llucìa Alos
16,
Celia Requena
17,
Isidro Bolumar
18,
Víctor Traves
19,
Ángel Pla
20,
Almudena Fernández-Orland
8,
Ane Jaka
3,
María Teresa Fernández-Figueras
21,
Nina Anika Richarz
3,
Ricardo Vieira
11,
Rafael Botella-Estrada
10,
Concepción Román-Curto
9,22,
Lara Ferrándiz-Pulido
8,
Nicolás Iglesias-Pena
7,
Carlos Ferrándiz
3,
Josep Malvehy
5,6,
Pietro Quaglino
4 and
Eduardo Nagore
17
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1
Dermatology Department, Instituto Dermatológico GlobalDerm, 14700 Palma del Río, Spain
2
Cutaneous Oncology Unit, Hospital San Juan de Dios, 14012 Córdoba, Spain
3
Dermatology Department, Hospital Universitari Germans Trials i Pujol, Institut d’Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
4
Medical Sciences Department, Section of Dermatology, University of Turin, 10124 Turin, Italy
5
Melanoma Unit, Dermatology Department, Hospital Clinic, Universitat de Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
6
Biomedical Research Networking Center on Rare Diseases (CIBERER), ISCIII, 28029 Barcelona, Spain
7
Departamento de Dermatología, Hospital Universitario de la Coruña, 15006 La Coruña, Spain
8
Melanoma Unit, Medical-&-Surgical Dermatology Department, Hospital Universitario Virgen Macarena, 41009 Sevilla, Spain
9
Dermatology Department, Complejo Asistencial Universitario de Salamanca, 37007 Salamanca, Spain
10
Dermatology Department, Hospital Universitario La Fe, 46126 Valencia, Spain
11
Departament of Dermatology, University Hospital of Coimbra, 3000-075 Coimbra, Portugal
12
Unidad de Investigación, Fundación Piel Sana, Academia Española de Dermatología, 28008 Madrid, Spain
13
Medical Sciences Department, Section of Surgical Pathology, University of Turin, 10124 Turin, Italy
14
Nuclear Medicine Department, Hospital Clinic Barcelona, Universitat de Barcelona, Institut d’investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
15
Surgery Department, Hospital Clinic, Universidad de Barcelona, 08036 Barcelona, Spain
16
Pathology Department, Hospital Clinic, Universidad de Barcelona, 08036 Barcelona, Spain
17
Dermatology Department, Instituto Valenciano de Oncología, 46009 Valencia, Spain
18
Surgery Department, Instituto Valenciano de Oncología, 46009 Valencia, Spain
19
Pathology Department, Instituto Valenciano de Oncología, 46009 Valencia, Spain
20
Otorhinolaringology Department, Instituto Valenciano de Oncología, 46009 Valencia, Spain
21
Pathology Department, Hospital Universitari Germans Trial i Pujol, 08916 Badalona, Spain
22
Instituto de Investigación Biomédica de Salamanca, Complejo Asistencial Universitario de Salamanca, 37007 Salamanca, Spain
*
Author to whom correspondence should be addressed.
These authors contributed equally to this study.
J. Clin. Med. 2021, 10(24), 5878; https://doi.org/10.3390/jcm10245878
Submission received: 14 November 2021 / Revised: 13 December 2021 / Accepted: 14 December 2021 / Published: 15 December 2021
(This article belongs to the Special Issue Cutaneous Melanoma: Current Diagnosis and Treatment Strategies)

Abstract

:
The therapeutic value of sentinel lymph node biopsy (SLNB) in thin melanoma remains controversial. The aim of this study is to determine the role of SLNB in the survival of thin melanomas (≤1 mm). A multicenter retrospective observational study was designed. A propensity score matching was performed to compare patients who underwent SLNB vs. observation. A multivariate Cox regression was used. A total of 1438 patients were matched by propensity score. There were no significant differences in melanoma-specific survival (MSS) between the SLNB and observation groups. Predictors of MSS in the multivariate model were age, tumor thickness, ulceration, and interferon treatment. Results were similar for disease-free survival and overall survival. The 5- and 10-year MSS rates for SLN-negative and -positive patients were 98.5% vs. 77.3% (p < 0.001) and 97.3% vs. 68.7% (p < 0.001), respectively. SLNB does not improve MSS in patients with thin melanoma. It also had no impact on DSF or OS. However, a considerable difference in MSS, DFS, and OS between SLN-positive and -negative patients exists, confirming its value as a prognostic procedure and therefore we recommend discussing the option of SLNB with patients.

1. Introduction

Sentinel lymph node biopsy (SLNB) is a commonly used procedure in the management of cutaneous melanoma [1]. Although the Multicenter Selective Lymphadenectomy Trial I (MSTL-I) showed that SLNB does not improve disease-specific survival in melanoma (MSS) [2], it did not include tumors with a Breslow thickness < 1.2 mm in the analysis. The therapeutic effect of SLNB in thin melanoma thus remains to be determined. This is important, particularly in our setting, where tumors with a Breslow thickness < 1 mm are the most common diagnosed melanomas [3]. In addition, SLNB is recommended for patients with stage T1b melanoma and stage T1a melanoma if there are other high-risk factors, such as a mitotic rate > 2 mitoses/mm2 [4], lymphovascular invasion, and young age [5].
The main aim of this study was to determine whether SLNB improves MSS in patients with thin tumors. Secondary objectives were to compare disease-free survival (DFS) and overall survival (OS) between patients who undergo SLNB and those who undergo observation and to examine the effect of SLN positivity on survival.

2. Materials and Methods

2.1. Study Population

We designed a multicenter observational study following the Strengthening the Reporting of Observational Studies in Epidemiology guidelines [6].
Patients were selected from the databases of nine hospitals that form part of the Sentinel Lymph Node Study Group in Melanoma (Sentimel). Seven of the hospitals are in Spain: Instituto Valenciano de Oncología in Valencia, Hospital Universitario de Salamanca in Salamanca, Hospital La Fe in Valencia, Hospital Universitario Virgen Macarena in Seville, Hospital de la Coruña in A Coruña, Hospital Germans Trias i Pujol in Badalona, and Hospital Clínic in Barcelona. The other two hospitals are in Portugal (Centro Hospitalar e Universitário de Coimbra) and Italy (University Hospital “Città della Salute e della Scienza di Torino”).
We included all patients aged ≥18 years who were registered in the hospital databases up to 31 December 2017 with a diagnosis of thin melanoma (Breslow thickness ≤ 1 mm) and no evidence of metastasis at diagnosis. 1 January 1998 was chosen as the start date for inclusion, as this is when most hospitals started to use SLNB in the management of melanoma [7]. SLNB is performed using a similar procedure at all the hospitals with any combination of vital blue dye, radioactive tracer, and preoperational lymphography (+/− preoperative PET-CT/CT) for SLN mapping. Thin primary melanomas are excised with a 1-cm margin, as recommended by clinical practice guidelines. The procedure for pathologic SLN examination has been described previously [8]. Hospital Clínic in Barcelona has been using the Minitub protocol (EORTC 1208: Minitub registration study) since 2011. The study was approved by the lead ethics committee, located at Hospital Universitario Reina Sofía in Cordoba (reference 3569).

2.2. Study Groups and Outcome Variables

The patients were divided into two groups: an SLNB group and an observation-only group. Patients in the SLNB group were further classified as SLN-positive or SLN-negative.
The outcome variables were DFS, MSS, and OS. Survival was defined as time in months from excision of the primary tumor to first recurrence (DFS), death due to melanoma (MSS), or death due to any cause (OS). Recurrence was classified as local recurrence or satellite, regional lymph node recurrence, or distant metastasis. In patients with multiple simultaneous recurrences, the most advanced type of recurrence was considered.

2.3. Propensity Score Matching

Propensity score matching is a relatively new statistical technique that controls for selection biases in non-randomized studies comparing two interventions or treatments [9]. It consists of matching patients according to their likelihood of being assigned to one group or another, in our case: SLNB or observation. The first step was to perform logistic regression with SLNB as the dependent variable and all the other variables as independent variables. The independent variables were chosen because of their potential prognostic value in melanoma [10] and comprised Breslow thickness [11], ulceration [11,12], regression [13,14], Clark level, microscopic satellitosis [15], mitotic rate [16], vascular invasion [16], tumor infiltrating lymphocytes [17], histologic subtype, age, sex, anatomic location [18], hospital, year, and treatment with interferon [19]. Histologic subtypes were “superficial spreading melanoma”, “nodular melanoma” and “other” histological subtypes. For the convergence of the models it was mandatory to reunify the rest of the histologic subgroups (lentigo maligna, acral lentiginous melanoma, …) into a single simple group (other).

2.4. Statistical Analysis

Between-group comparisons were made using the Mann–Whitney U test and the t test for qualitative and quantitative variables respectively. Breslow thickness and age were log-transformed to avoid skewed distribution. Separate models were built for DFS, MSS, and OS. Survival times were calculated from excision of the primary tumor to the event in question. Cases with no events up to the date of the last follow-up were treated as censored data. Survival curves estimated using the Kaplan–Meier method were compared using the log-rank test to compare survival between patients in the SLNB and observation-only groups. The same method was used to compare SLN-positive and SLN-negative patients. Univariate Cox regression was used to assess the effect of each variable on survival according to the performance of SLNB or not. A multivariate model was built to analyze the impact on survival of all variables with a significance level of p < 0.2 in the univariate analysis.

2.5. Missing Data

Assuming that missing data were missing at random, we generated 20 complete datasets using multivariate imputation by chained equations (mi impute chained procedure in Stata). The procedure included all variables that were to be subsequently analyzed in addition to any variables that could help explain the missing data. Each of 20 imputed datasets was analyzed using Cox regression to fit the model of interest to the outcome variables (DFS, MSS, and OS). Finally, the results of the complete datasets were combined into a single set of estimates using Rubin rules [20]. All analyses were performed in STATA v.14.1 (Stata Corp. 2015. Stata Statistical Software: Release 14).

3. Results

3.1. Study Population Characteristics

We included 5049 patients with thin localized melanoma (≤1 mm) at diagnosis; 1083 had undergone SLNB and 3966 observation only (Figure 1). In total, 1438 patients were matched by propensity scores.
Before matching, patients in the observation group were more likely to be women (58% vs. 53%, p < 0.001) and to have melanoma of the head and neck (14% vs. 7%, p < 0.001) and less likely to have ulceration (1% vs. 10%, p < 0.001), regression (26% vs. 45%, p < 0.001), and a Clark level IV (6% vs. 26%, p < 0.001). They also had lower mitotic rates. There were no significant differences between the groups after matching (Table 1).

3.2. Survival Rates

Median follow-up was 61 months. During this time, there were 82 recurrences (5.7%), 46 melanoma-specific deaths (3.2%), and 74 deaths due to another cause (5.1%); 8.3% of patients in the SLNB group and 10.3% of those in the observation group were lost to follow-up.
There were no significant differences in MSS between the SLNB and observation groups. The respective 5- and 10-year survival rates were 97.4% vs. 97.1 % and 95.3% vs. 95.6%. The corresponding 5- and 10-year rates for DFS were 95.3% vs. 94.3% and 90.8% vs. 91.8%. The differences for 5-year and 10-year OS were also non-significant (Figure 2).
When all other variables were controlled for in the multivariate analysis, SLNB was not a significant predictor of either MSS or DFS. It was, however, an independent predictor of OS (adjusted hazard ratio, 0.61; 95% CI, 0.37–1; p = 0.05).

3.2.1. Melanoma-Specific Survival

The predictors of MSS in the multivariate model were age, tumor thickness, ulceration, and interferon treatment (Table 2).

3.2.2. Disease-Free Survival

The independent predictors of DFS were age, histologic subtype other than superficial spreading melanoma and nodular melanoma, ulceration, Clark level, mitotic rate, and interferon treatment (Table 3).

3.2.3. Overall Survival

The independent predictors of OS, in addition to SLNB, were sex, age, ulceration, Clark level, and interferon treatment (Table 4).

3.3. Prognostic Significance of SLNB

Forty-two patients in the SLNB group (5.8%) were SLN-positive, but seven false negatives were detected during follow-up. The overall false negative rate was 14.3%, which was calculated by dividing the number of false negatives by the sum of positive cases and false negatives according to the method described by van Akkooi et al. [21].
The 5- and 10-year MSS rates for SLN-negative and -positive patients were 98.5% vs. 77.3% (p < 0.001) and 97.3% vs. 68.7% (p < 0.001), respectively. The corresponding rates for the other survival categories were 96.6% vs. 60.9% (p < 0.001) and 94.6% vs 48.9% (p < 0.001) for DFS and 97.3% vs. 78.9% (p < 0.001) and 95.5% vs. 66.6% (p < 0.001) for OS (Figure 3).

4. Discussion

The main conclusion of this study is that SLNB does not improve MSS in patients with thin melanoma. It also had no impact on DSF or OS. The conclusion for MSS is the same as that reached in the MSLT-I [2] but for melanomas with a Breslow thickness < 1 mm.
The theoretical basis for the introduction of SLNB in the treatment of cutaneous melanoma in the 1990s was that the regional lymph nodes act as an incubator for subsequent distant spread [22]. Our focus on thin melanomas is justified as these tumors have a different pattern of spread. Compared with thicker melanomas, they have a greater propensity for locoregional metastasis and are less likely to spread to distant sites [21]. Our results, however, indicate the presence of synchronous regional and distant metastasis in thin melanoma, which would explain the absence of a significant survival benefit for SLNB in this setting [23,24,25].
Very few observational studies have analyzed the impact of SLNB on survival in patients with thin melanoma. Using data from the Surveillance, Epidemiology, and End Results (SEER) program, Sperry et al. [26] found no difference in MSS in 1104 propensity score-matched patients with thin melanoma who had undergone SLNB or nodal observation. More recently, Murtha et al. [27], using the same database, reported a significant difference in OS but not MSS over a median follow-up period of 16 months for a population of 3439 patients with melanoma with a thickness of 0.75 to <1 mm. Finally, in another propensity score matching study using data from the US National Cancer Data Base, Sinnamon et al. [28] found no differences in OS between 4262 pairs of melanoma patients with a Breslow thickness of 0.5 to 0.7 mm. They did, however, find a difference for OS among patients with tumors measuring 0.8 to 1.0 mm. One limitation of their study, however, was that the database does not contain information on MSS.
Our analysis of SLN-positive and -negative patients show worse survival rates than in similar studies [29,30], probably because of differences in patient selection criteria. These differences in survival could justify the use of new adjuvant therapies and should be discussed with patients [5].
The main limitation of this study is its retrospective design. The groups may not have been properly balanced as not all potential confounders were considered (e.g., comorbidities and performance status). Our study may also be underpowered, as it has been calculated that 6500 patients would be needed to detect a protective effect for SLNB using a similar design to the MSLT-1, based on a power of 90%, a follow-up period of 5 years, and an estimated hazard ratio of 0.8 for SLNB [26]. Furthermore, we did not specifically analyze time to recurrence at regional lymph nodes; the only expected benefit of the SLNB according to previous studies focused on thicker tumors.
Ulceration and thickness remain as independent prognostic factors associated with MSS survival in thin melanomas. Age also remains as an independent prognostic factor of MSS. It has been evidenced that patients at extreme age have a distinct natural history [31,32]. These data are congruent with the AJCC as ulceration is established as a variable that increases the staging according to a certain thickness while melanoma thicknesses close to 1 mm are already considered another stage [7]. It remains to be seen whether advanced age may contribute in the future to defining these melanomas with a worse prognosis.
The fact that interferon treatment is associated to worse MSS (HR 7.29 p < 0.001) should be considered as subsidiary of positivity of the SLNB, because the result of the procedure was not included in the analysis and interferon treatment was only indicated in the cases of lymph node positivity in thin melanomas as indicated in the active guide lines during the period of the study.

5. Conclusions

SLNB is currently used for staging purposes in thin melanoma. Our study of a large cohort of patients with thin melanoma did not show that SLNB modifies survival in this setting. We did, however, observe a considerable difference in MSS, DFS, and OS between SLN-positive and -negative patients and therefore recommend discussing the option of SLNB with patients.

Author Contributions

A.T.-V., A.B. (Aram Boada) and E.N. had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: A.T.-V. and E.N. Acquisition, analysis, and interpretation of data: S.O.-A., P.C., C.C., S.V.-S., R.P., A.T., S.P. (Sebasian Podlipnik), R.R., L.A., C.R., I.B., V.T., Á.P., A.F.-O., A.J., M.T.F.-F., N.A.R., R.B.-E., C.R.-C., L.F.-P., N.I.-P., C.F., J.M. and P.Q. Drafting of the manuscript: A.T.-V. Critical revision of the manuscript for important intellectual content: S.R., S.P. (Susana Puig), A.B. (Aram Boada), S.P. (Sabela Paradela), D.M.-R., J.C., B.d.U.-B., M.A.D.-G., A.B. (Ana Brinca), R.V. and E.N. Statistical analysis: M.A.D.-G. All authors have read and agreed to the published version of the manuscript.

Funding

Research at the Melanoma Unit in Barcelona is partially funded by Spanish Fondo de Investigaciones Sanitarias grants 12/00840, PI15/00956, 15/00716, and 18/00419; CIBER de Enfermedades Raras of the Instituto de Salud Carlos III, Spain, co-financed by the European Development Regional Fund “A way to achieve Europe” ERDF; AGAUR 2014_SGR_603 of the Catalan Government, Spain; European Commission under the 6th Framework Programme, Contract No. LSHC-CT-2006-018702 (GenoMEL) and by the European Commission under the 7th Framework Programme, and by the European Commission under the H2020 programme Qualitop Diagnoptics; a grant from “Fundació La Marató de TV3, 201331-30”, Catalonia, Spain, and a grant from “Fundación Científica de la Asociación Española Contra el Cáncer”, Spain; J.C. is partially supported by the grants PI18/000587 (Instituto de Salud Carlos III) and GRS 1835/A/18 (Gerencia Regional de Salud de Castilla y León), and by the Programa de Intensificación de la Actividad Investigadora de la Gerencia Regional de Salud de Castilla y León (INT/M/10/19), Spain. Research at Turin Melanoma research Unit received funding specifically dedicated to the Department of Medical Sciences, University of Turin from Italian Ministry for Education, University and Research (Ministero dell’Istruzione, dell’Università e della Ricerca—MIUR) under the program “Dipartimenti di Eccellenza 2018–2022”, Project n° D15D18000410001.

Institutional Review Board Statement

The study was conducted according to the principles of the Declaration of Helsinki, and approved by the ethics committee at Hospital Reina Sofía in Córdoba (reference 3569).

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

Thanks to our patients and their families who are the main reason for our studies, to Anne Murray for her help with English editing and correction of the manuscript in English, and to the Fondazione Lanzavecchia-Lastretti for their continued support.

Conflicts of Interest

The authors have no conflict of interest to declare. The sponsors had no role in the design and conduct of the study; in the collection, analysis, and interpretation of data, nor in the preparation, review, or approval of the manuscript.

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Figure 1. Flow chart of the study population. PSM denotes propensity score matching; SLNB, sentinel lymph node biopsy.
Figure 1. Flow chart of the study population. PSM denotes propensity score matching; SLNB, sentinel lymph node biopsy.
Jcm 10 05878 g001
Figure 2. Estimated disease-free survival (a), melanoma-specific survival (b), and overall survival (c) according to study group. Survival curves calculated using the Kaplan–Meier method according to study group in the propensity score-matched sample (n = 1438). SLNB denotes sentinel lymph node biopsy.
Figure 2. Estimated disease-free survival (a), melanoma-specific survival (b), and overall survival (c) according to study group. Survival curves calculated using the Kaplan–Meier method according to study group in the propensity score-matched sample (n = 1438). SLNB denotes sentinel lymph node biopsy.
Jcm 10 05878 g002
Figure 3. Estimated disease-free survival (a), melanoma-specific survival (b), and overall survival (c) according to sentinel lymph node status.
Figure 3. Estimated disease-free survival (a), melanoma-specific survival (b), and overall survival (c) according to sentinel lymph node status.
Jcm 10 05878 g003
Table 1. Characteristics of patients with thin cutaneous melanoma (<1 mm) according to study group (SLNB vs observation) before and after propensity score matching.
Table 1. Characteristics of patients with thin cutaneous melanoma (<1 mm) according to study group (SLNB vs observation) before and after propensity score matching.
CharacteristicsBefore Propensity Score Matching After Propensity Score Matching
OBSERVATION SLNBp-ValueOBSERVATION SLNBp-Value
n = 3966n = 1083n = 719n = 719
YearN (%)N (%)<0.001N (%)N (%)0.675
≤20001295 (33)97 (9) 103 (14)88 (12)
2001–2006827 (21)294 (27) 186 (26)197 (27)
2007–2011986 (25)334 (31) 227 (32)227 (32)
2012–2017858 (22)358 (33) 203 (28)207 (29)
Hospital
Salamanca108 (3)21 (2)<0.00112 (2)14 (2)0.544
Valencia IVO440 (11)218 (20) 119 (17)132 (18)
Turin1494 (38)296 (27) 187 (26)204 (28)
Barcelona1017 (26)202 (19) 163 (23)160 (22)
Badalona361 (9)194 (18) 133 (18)105 (15)
Coimbra65 (2)14 (1) 14 (2)12 (2)
A Coruña202 (5)74 (7) 51 (7)43 (6)
Sevilla203 (5)40 (4) 23 (3)31 (4)
Valencia La Fe76 (2)24 (2) 17 (2)18 (3)
Sex 0.001 0.459
Male1646 (42)509 (47) 324 (45)338 (47)
Female2320 (58)573 (53) 395 (55)381 (53)
Mean age (sd), y52.4 (16.4)51.9 (14.7)0.337252.9 (16.7)52.5 (14.9)0.6422
Tumor location <0.001 0.266
Head/neck528 (14)80 (7) 86 (12)67 (9)
Trunk1579 (41)473 (44) 300 (42)307 (43)
Extremities (upper and lower)1725 (45)518 (48) 333 (46)345 (48)
Log tumor thickness. median (p25–p75)−0.7 (−0.9–−0.4)−0.2 (−0.5–−0.1)<0.001−0.4 (−0.6–−0.2)−0.7 (−0.3–−0.1)0.063
Histologic subtype <0.001 0.623
Superficial spreading melanoma3293 (84)871 (81) 578 (80)592 (82)
Nodular melanoma45 (1)54 (5) 23 (3)22 (3)
Other588 (15)145 (14) 118 (16)105 (15)
Ulceration <0.001 0.368
No3467 (99)890 (90) 673 (94)681 (95)
Yes50 (1)100 (10) 46 (6)38 (5)
Regression <0.001 0.872
No2422 (74)494 (55) 425 (59)428 (60)
Yes845 (26)399 (45) 294 (41)291 (40)
Microscopic satellite 0.1265 1.000
No1529 (100)584 (99) 710 (99)711 (99)
Yes4 (0)5 (1) 9 (1)8 (1)
Tumor infiltrating lymphocytes 0.5505 0.473
No 272 (27)67 (27) 192 (27)175 (24)
Non-brisk580 (57)134 (54) 377 (52)399 (55)
Brisk169 (17)48 (19) 150 (21)145 (20)
Vascular invasion 0.744 0.803
No1655 (100)608 (99) 712 (99)710 (99)
Yes8 (0)4 (1) 7 (1)9 (1)
Interferon treatment <0.001 0.358
No2361 (99)738 (95) 700 (97)694 (97)
Yes20 (1)37 (5) 19 (3)25 (3)
Clark level <0.001 0.838
I-III2897 (94)755 (74) 588 (82)585 (81)
IV184 (6)263 (26) 131 (18)134 (19)
Mitotic rate (mitoses/mm2) <0.001 0.991
01491 (82)248 (34) 341 (47)339 (47)
1225 (12)282 (39) 247 (34)252 (35)
255 (3)116 (16) 84 (12)81 (11)
≥349 (3)82 (11) 47 (7)47 (7)
Log, logarithm; SLNB, sentinel lymph node biopsy.
Table 2. Univariate and multivariate analysis of predictors of melanoma-specific survival in patients included in the study (n = 1438).
Table 2. Univariate and multivariate analysis of predictors of melanoma-specific survival in patients included in the study (n = 1438).
Crude Univariate Analysis Adjusted Multivariate Analysis
HR95% CI LL95% CI ULp-Value HR95% CI LL95% CI ULp-Value
SLNB SLNB
NoRef---NoRef---
Yes0.960.531.730.884Yes0.840.451.560.575
Year
≤2000Ref---
2001–20060.730.351.540.410
2007–20110.980.422.270.958
2012–20170.670.182.540.558
Hospital
SalamancaRef---
Valencia IVO0.540.074.290.562
Turin0.480.063.740.487
Barcelona0.740.105.710.772
Badalona0.390.053.220.379
CoimbraNA
A Coruña0.250.024.010.328
SevillaNA
Valencia La FeNA
Sex
MaleRef---
Female0.570.311.020.057
Age1.021.001.040.076Age1.031.011.050.011
Log age1.980.735.340.18
Tumor location
Head/neckRef---
Trunk1.390.484.020.541
Extremities (upper and lower)0.850.292.530.771
Tumor thickness13.712.6869.960.002
Log tumor thickness4.761.5614.510.006Log tumor thickness3.821.2311.810.020
Histologic subtype
Superficial spreading melanomaRef---
Nodular melanoma4.101.5910.620.004
Other1.940.924.080.082
Ulceration Ulceration
NoRef---NoRef---
Yes3.231.437.280.005Yes2.661.116.380.028
Regression
NoRef---
Yes0.970.501.890.922
Microscopic satellite
NoRef---
Yes5.410.7240.510.098
Tumor infiltrating lymphocytes
1Ref---
20.900.411.980.787
30.620.142.670.517
Vascular invasion
NoRef---
YesNA
Interferon Interferon
NoRef---NoRef---
Yes7.703.4517.190.000Yes7.292.9418.060.000
Clark level
I-II-IIIRef---
IV1.920.933.950.076
Mitotic rate
0Ref---
11.670.664.200.276
22.280.638.200.204
≥34.161.3412.890.014
HR, hazard ratio; LL, lower limit; Log, logarithm; SLNB, sentinel lymph node biopsy; UL, upper limit.
Table 3. Univariate and multivariate analysis of predictors of disease-free survival in patients included in the study (n = 1438).
Table 3. Univariate and multivariate analysis of predictors of disease-free survival in patients included in the study (n = 1438).
Crude Univariate Analysis Adjusted Multivariate Analysis
HR95% CI LL95% CI ULp-Value HR95% CI LL95% CI ULp-Value
SLNB SLNB
NoRef---NoRef---
Yes1.110.721.730.634Yes0.840.491.430.509
Year
≤2000Ref---
2001–20060.670.391.150.142
2007–20110.620.341.140.124
2012–20170.420.171.070.068
Hospital
SalamancaRef---
Valencia IVO1.340.1810.010.776
Turin1.250.179.210.829
Barcelona1.320.189.890.785
Badalona0.580.074.640.606
CoimbraNA
A Coruña0.500.055.530.573
SevillaNA
Valencia La Fe0.950.0615.160.970
Gender
MaleRef---
Female0.730.471.120.152
Age1.021.011.040.006Age1.031.011.040.003
Log Age2.471.175.230.018
Localization
Head/NeckRef---
Trunk0.950.442.070.907
Extremities (upper and lower)1.020.482.170.965
Tumor thickness7.322.3323.060.001
Log tumor thickness3.031.436.400.004
Histologic subtype Histologic subtype
Superficial spreading melanomaRef---Superficial spreading melanomaRef---
Nodular melanoma5.402.7310.670.000Nodular melanoma1.580.564.470.389
Others2.361.394.010.001Others2.511.364.630.003
Ulceration Ulceration
NoRef---NoRef---
Yes4.142.347.330.000Yes3.061.406.700.005
Regression
NoRef---
Yes0.690.411.160.161
Microscopic satellite
NoRef---
Yes5.541.1526.580.033
Tumor infiltrating lymphocytes
NoRef---
Non-brisk1.020.531.940.960
Brisk0.910.282.940.873
Vascular invasion
NoRef---
YesNA
Interferon Interferon treatment
NoRef---NoRef---
Yes10.805.9719.520.000Yes15.127.3631.070.000
Clark level Clark level
I-II-IIIRef---I-II-IIIRef---
IV2.171.303.610.003IV2.381.354.180.003
Mitotic rate Mitotic rate
0Ref---0Ref---
11.720.853.500.13112.030.934.420.074
23.061.267.440.01423.081.158.210.025
≥37.303.3815.780.0003 or more7.663.0219.450.000
HR, hazard ratio; LL, lower limit; Log, logarithm; SLNB, sentinel lymph node biopsy; UL, upper limit.
Table 4. Univariate and multivariate analysis of predictors of overall survival in patients included in the study (n = 1438).
Table 4. Univariate and multivariate analysis of predictors of overall survival in patients included in the study (n = 1438).
Crude Univariate Analysis Adjusted Multivariate Analysis
HRLL 95%CIUL 95%CIp-Value HRLL 95%CIUL 95%CIp-Value
SLNB SLNB
NoRef---NoRef---
Yes0.740.461.190.211Yes0.610.371.000.050
Year
≤2000Ref---
2001–20061.060.561.990.857
2007–20111.150.562.360.710
2012–20171.690.714.020.236
Hospital
SalamancaRef---
Valencia IVO0.970.137.370.980
Turin0.470.063.620.468
Barcelona1.110.158.320.922
Badalona0.930.127.100.944
Coimbra3.290.2053.370.402
A Coruña1.250.1510.710.838
Sevilla0.660.067.340.738
Valencia La FeNA
Sex Sex
MaleRef---MaleRef---
Female0.410.250.670.000Female0.480.290.790.004
Age1.051.041.070.000Age1.051.031.070.000
Log age10.714.1527.620.000
Tumor location
Head/neckRef---
Trunk0.840.401.750.646
Extremities (upper and lower)0.680.331.410.302
Tumor thickness4.471.4014.330.012
Log tumor thickness2.381.125.030.023
Histologic subtype
Superficial spreading melanomaRef---
Nodular melanoma2.360.945.940.068
Other1.520.832.790.177
Ulceration Ulceration
NoRef---NoRef---
Yes2.751.415.380.003Yes2.581.255.340.011
Regression
NoRef---
Yes1.320.812.180.267
Microscopic satellite
NoRef---
Yes3.430.5123.230.202
Tumor infiltrating lymphocytes
NoRef---
Non-Brisk0.730.381.410.343
Brisk0.490.151.680.254
Vascular invasion
NoRef---
YesNA
Interferon treatment Interferon treatment
NoRef---NoRef---
Yes4.282.029.050.000Yes5.692.4313.310.000
Clark level Clark level
I-II-IIIRef---I-II-IIIRef---
IV2.001.153.450.014IV1.861.063.270.031
Mitotic rate
0Ref---
11.570.803.090.190
21.910.754.890.176
≥32.611.046.540.041
HR, hazard ratio; LL, lower limit; Log, logarithm; SLNB, sentinel lymph node biopsy; UL, upper limit.
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Tejera-Vaquerizo, A.; Boada, A.; Ribero, S.; Puig, S.; Paradela, S.; Moreno-Ramírez, D.; Cañueto, J.; de Unamuno-Bustos, B.; Brinca, A.; Descalzo-Gallego, M.A.; et al. Sentinel Lymph Node Biopsy vs. Observation in Thin Melanoma: A Multicenter Propensity Score Matching Study. J. Clin. Med. 2021, 10, 5878. https://doi.org/10.3390/jcm10245878

AMA Style

Tejera-Vaquerizo A, Boada A, Ribero S, Puig S, Paradela S, Moreno-Ramírez D, Cañueto J, de Unamuno-Bustos B, Brinca A, Descalzo-Gallego MA, et al. Sentinel Lymph Node Biopsy vs. Observation in Thin Melanoma: A Multicenter Propensity Score Matching Study. Journal of Clinical Medicine. 2021; 10(24):5878. https://doi.org/10.3390/jcm10245878

Chicago/Turabian Style

Tejera-Vaquerizo, Antonio, Aram Boada, Simone Ribero, Susana Puig, Sabela Paradela, David Moreno-Ramírez, Javier Cañueto, Blanca de Unamuno-Bustos, Ana Brinca, Miguel A. Descalzo-Gallego, and et al. 2021. "Sentinel Lymph Node Biopsy vs. Observation in Thin Melanoma: A Multicenter Propensity Score Matching Study" Journal of Clinical Medicine 10, no. 24: 5878. https://doi.org/10.3390/jcm10245878

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