title: Role of sentinel lymph node biopsy in patients with Merkel cell carcinoma: statistical analysis of 403 reported cases.
abstract: BACKGROUND
  Merkel cell carcinoma (MCC) is a rare cutaneous malignancy with a high rate of nodal metastasis. Sentinel lymph node biopsy (SLNB) is used in MCC and other cancers to identify regional node micrometastases in patients with clinically negative nodes; however, whether SLN status is associated with recurrence or prognosis in MCC is unclear.
  
  
  METHODS
  A statistical analysis was performed of 397 published cases of MCC with SLNB results from 22 reports and 6 new cases, in order to elucidate any correlation between SLN status and recurrence, and to determine false-negative rates for SLNB.
  
  
  RESULTS
  Of these 403 cases, 128 (31.8 %) had positive SLNs; 16 of these 128 (12.5 %) developed recurrence (6 nodal, 10 distant). Of 275 patients with negative SLNs, 27 (9.8 %) developed recurrence (19 nodal, 8 distant). Patients with positive SLNs had a greater risk of distant metastasis (OR 2.82; P = 0.037; 95 % CI 1.089-7.347). The false-negative rate for SLNB in all 403 patients was 12.9 %. Use of the immunohistochemical approach to diagnosis of micrometastasis with anti-CK20 antibody did not affect the false-negative rate.
  
  
  CONCLUSIONS
  Patients with positive SLNs had a greater risk of distant metastasis in MCC; positive SLN was an important prognostic factor in MCC. Further studies using standardized, more-sensitive techniques to examine entire SLNs may decrease the false-negative rate, and improve the significance of SLNB in MCC.
authors.affiliation: Department of Dermatology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, 814-0133, Japan, shibayoshi1978@hotmail.com.
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Shibayama
authors.forename: Shinichi
authors.initials: S
authors.lastname: Imafuku
authors.forename: Akira
authors.initials: A
authors.lastname: Takahashi
authors.forename: Juichiro
authors.initials: J
authors.lastname: Nakayama
mesh_terms: D015266:Carcinoma, Merkel Cell / Q000473:pathology*; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D061206:Neoplasm Micrometastasis / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging / Q000379:methods; D011379:Prognosis; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D012878:Skin Neoplasms / Q000473:pathology*