title: Selective radiotherapy for the treatment of head and neck Merkel cell carcinoma.
abstract: BACKGROUND
  The role of radiotherapy (RT) in the management of Merkel cell carcinoma (MCC) is controversial. The authors of this report evaluated the rates and patterns of failure in a selected group of patients who underwent RT for MCC of the head and neck (HN).
  
  
  METHODS
  The records of 145 consecutive patients with MCC of the HN who presented to the authors' institution between 1988 and 2009 were reviewed. Only patients who received RT at the institution were included. The cumulative incidence of locoregional failure (LRF), distant metastatic failure (DMF), disease progression (DP) and disease-specific death (DSD) were estimated with death as a competing risk.
  
  
  RESULTS
  Forty-eight patients were identified. The median follow-up was 51 months (range, 6-220 months) for living patients. LRF developed in 5 patients (10%), and those patients had a median time to recurrence of 3 months. Two of the 5 LRFs were local and developed at the edge of the treatment field; the remaining 3 LRFs were in lymph nodes and occurred outside the treatment field. DMF developed in 12 patients (25%). The estimated 5-year cumulative incidences of LRF, DP, and DSD were 10%, 30%, and 21%, respectively. Acute toxicities included 5 episodes (10%) of grade 3 dermatitis and 1 episode (2%) of grade 3 mucositis.
  
  
  CONCLUSIONS
  The authors report a site-specific series of patients with HN MCC who received RT. In this group of patients with adverse features, RT was well tolerated, and LRF was low. The propensity for MCC to recur at the edge of the treatment field suggests that generous margins are appropriate when RT is administered.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center and New York University School of Medicine, New York, New York, USA. lokb@mskcc.org
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lok
authors.forename: Sabrina
authors.initials: S
authors.lastname: Khan
authors.forename: Robert
authors.initials: R
authors.lastname: Mutter
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Liu
authors.forename: Ryan
authors.initials: R
authors.lastname: Fields
authors.forename: Melissa
authors.initials: M
authors.lastname: Pulitzer
authors.forename: Weiji
authors.initials: W
authors.lastname: Shi
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Dennis
authors.initials: D
authors.lastname: Kraus
authors.forename: David
authors.initials: D
authors.lastname: Pfister
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Busam
authors.forename: Isaac
authors.initials: I
authors.lastname: Brownell
authors.forename: Nancy
authors.initials: N
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018714:Radiotherapy, Adjuvant; D017211:Treatment Failure