title: Merkel cell carcinoma: value of sentinel lymph-node status and adjuvant radiation therapy.
abstract: Sentinel lymph-node (LN) biopsy (SLNB) is a valuable tool to assess the regional LN status in Merkel cell carcinoma (MCC). However, its prognostic value is still debated. This study was undertaken to assess SLNB usefulness for MCC management and to determine the impact of SLNB status on disease-free survival (DFS) and overall survival (OS) by comparing SLNB-positive versus -negative patients according to demographic, clinical and treatment characteristics.
  
  
  
  In this retrospective, multicenter observational study, SLNB was proposed to all patients referred for clinically N0 MCC. Treatment schedule consisted of wide-margin surgical resection of primary MCC followed by adjuvant radiation therapy (aRT) to the primary site and, for SLNB-positive patients, radical LN dissection followed by regional aRT. Univariate and multivariate analyses determined factors associated with DFS and OS.
  
  
  
  Among 87 patients with successful SLNB, 21 (24.1%) were SLNB-positive. Median follow-up for the entire series was 39 months; respective 3-year DFS and OS rates were 73% and 81.4%, respectively. Univariate analysis (all patients) identified SLNB-negativity as being associated with prolonged OS (P = 0.013) and aRT (all sites considered) was associated with longer DFS (P = 0.004) and OS (P = 0.018). Multivariate analysis (all patients) retained SLNB status and aRT (all sites considered) as being associated with improved DFS (P = 0.014 and 0.0008) and OS (P = 0.0020 and 0.0019). Moreover, for SLNB-negative patients, tumor-bed irradiation was also significantly associated with prolonged DFS (P = 0.006) and OS (P = 0.014).
  
  
  
  The present study demonstrates that SLNB-negativity is a strong predictor of longer DFS and OS in stage I and II MCC patients. The similar benefit for aRT on tumor bed observed in this study has to be confirmed by a prospective study. The results advocate for SLNB being considered to all MCC patients.
authors.affiliation: Department of Dermatology, APHP, Hôpital Cochin, Paris.
authors.forename: A
authors.initials: A
authors.lastname: Servy
authors.affiliation: University of Paris 13, Bobigny Department of Dermatology, APHP, Hôpital Avicenne, Bobigny UMR-946 INSERM, Genetic Variation and Human Diseases Unit (UMR-946), Paris eve.maubec@inserm.fr.
authors.forename: E
authors.initials: E
authors.lastname: Maubec
authors.affiliation: UMR-946 INSERM, Genetic Variation and Human Diseases Unit (UMR-946), Paris University of Pierre et Marie Curie, Paris University of Paris Diderot, Paris.
authors.forename: P E
authors.initials: PE
authors.lastname: Sugier
authors.affiliation: Department of Dermatology, Hôpital Robert-Debré, Reims.
authors.forename: F
authors.initials: F
authors.lastname: Grange
authors.affiliation: Department of Dermatology, CHU Estaing, Clermont-Ferrand.
authors.forename: S
authors.initials: S
authors.lastname: Mansard
authors.affiliation: Department of Oncology, Centre Eugène-Marquis, Rennes.
authors.forename: T
authors.initials: T
authors.lastname: Lesimple
authors.affiliation: Department of Pathology, APHP, Hôpital Bichat, Paris.
authors.forename: E
authors.initials: E
authors.lastname: Marinho
authors.affiliation: Department of Surgery, Institut Curie, Paris.
authors.forename: B
authors.initials: B
authors.lastname: Couturaud
authors.affiliation: Department of Surgery, Institut Curie, Paris.
authors.forename: A
authors.initials: A
authors.lastname: Girod
authors.affiliation: University of Paris Diderot, Paris Department of Otorhinolaryngology, APHP, Hôpital Bichat, Paris.
authors.forename: S
authors.initials: S
authors.lastname: Albert
authors.affiliation: Department of Oncology, Institut Curie, Paris.
authors.forename: R
authors.initials: R
authors.lastname: Dendale
authors.affiliation: Department of Radiotherapy, Clinique de la Porte de Saint-Cloud, Boulogne.
authors.forename: E
authors.initials: E
authors.lastname: Calitchi
authors.affiliation: University of Paris Diderot, Paris Department of Nuclear Medicine, APHP, Hôpital Lariboisière, Paris, Descartes.
authors.forename: L
authors.initials: L
authors.lastname: Sarda
authors.affiliation: Department of Dermatology, APHP, Hôpital Cochin, Paris.
authors.forename: J
authors.initials: J
authors.lastname: Chanal
authors.affiliation: Department of Pathology, APHP, Hôpital Bichat, Paris.
authors.forename: L
authors.initials: L
authors.lastname: Deschamps
authors.affiliation: Institut Curie, Department of Pathology, Paris.
authors.forename: X
authors.initials: X
authors.lastname: Sastre-Garau
authors.affiliation: University of Paris 13, Bobigny Department of Dermatology, APHP, Hôpital Avicenne, Bobigny.
authors.forename: L
authors.initials: L
authors.lastname: Laroche
authors.affiliation: University of Paris Diderot, Paris Department of Dermatology, APHP, Hôpital Bichat, Paris.
authors.forename: B
authors.initials: B
authors.lastname: Crickx
authors.affiliation: Department of Dermatology, APHP, Hôpital Cochin, Paris University of Paris Descartes, Paris, France.
authors.forename: M F
authors.initials: MF
authors.lastname: Avril
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D000071036:Sentinel Lymph Node / Q000473:pathology / Q000601:surgery; D021701:Sentinel Lymph Node Biopsy; D016896:Treatment Outcome
keywords: Merkel cell carcinoma; adjuvant radiation therapy; disease-free survival; overall survival; sentinel lymph-node biopsy