title: Effect of host, tumor, diagnostic, and treatment variables on outcomes in a large cohort with Merkel cell carcinoma.
abstract: OBJECTIVE
  Merkel cell carcinoma (MCC) is a rare, aggressive, neuroendocrine-derived skin cancer with high rates of recurrence and associated mortality. Few published studies have used comprehensive patient data and long-term follow-up to examine factors that predict MCC outcomes.
  
  
  OBJECTIVE
  To characterize MCC in a large defined-population cohort and analyze predictors of disease recurrence and survival.
  Retrospective cohort study of 218 patients with MCC from the cancer registry of Kaiser Permanente Northern California, a large integrated health care delivery system. Patients were diagnosed as having MCC and followed up from January 1, 1995, through December 31, 2009. We examined host (age, sex, race, and immunosuppression), tumor (anatomic site, size, and extent), diagnostic (results of imaging and pathologic nodal evaluation), and treatment (surgery, radiation therapy, and chemotherapy) variables for their association with MCC outcomes.
  
  
  METHODS
  Host, tumor, diagnostic, and treatment factors.
  
  
  METHODS
  Recurrence (locoregional and distant) of MCC and patient survival (overall and MCC specific).
  
  
  RESULTS
  We estimated adjusted hazard ratios (AHRs) and 95% CIs for outcomes using Cox proportional hazards regression models. After adjustment for host, tumor, diagnostic, and treatment variables, tumor extent (categorized as local, regional, and distant) remained significantly associated with all outcomes. Immunosuppression was associated with higher MCC-specific mortality (AHR, 4.9 [95% CI, 1.7-14.4]), and an unknown primary site was associated with a lower risk for distant metastasis (0.1 [0.0-0.7]) and improved survival (0.4 [0.2-0.9]). Pathological nodal evaluation was associated with a lower risk for metastasis (AHR, 0.2 [95% CI, 0.0-1.0]) and improved survival. Radiation treatment was associated with a decreased risk for locoregional recurrence (AHR, 0.3 [95% CI, 0.1-0.6]), whereas chemotherapy was not associated with any alteration in outcomes.
  
  
  CONCLUSIONS
  Tumor site and extent, results of pathologic nodal evaluation, and the presence of radiation treatment were associated with MCC recurrence. Immunosuppression, tumor extent, and results of pathologic nodal evaluation were associated with MCC-specific survival, whereas chemotherapy was not associated with any outcomes. Our findings may help to inform diagnostic and therapeutic management of MCCs.
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland2Department of Dermatology, University of California at San Francisco.
authors.forename: Maryam M
authors.initials: MM
authors.lastname: Asgari
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Sokil
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland.
authors.forename: E Margaret
authors.initials: EM
authors.lastname: Warton
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, Washington.
authors.forename: Jayasri
authors.initials: J
authors.lastname: Iyer
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, Washington.
authors.forename: Kelly G
authors.initials: KG
authors.lastname: Paulson
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, Washington4Division of Dermatology, Department of Medicine, University of Washington, Seattle.
authors.forename: Paul
authors.initials: P
authors.lastname: Nghiem
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002140:California; D015266:Carcinoma, Merkel Cell / Q000175:diagnosis / Q000556:secondary* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007165:Immunosuppression Therapy; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D009382:Neoplasms, Unknown Primary / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D012737:Sex Factors; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy