title: Percentage of smudge cells on routine blood smear predicts survival in chronic lymphocytic leukemia.
abstract: OBJECTIVE
  Smudge cells are ruptured chronic lymphocytic leukemia (CLL) cells appearing on the blood smears of CLL patients. Our recent findings suggest that the number of smudge cells may have important biologic correlations rather than being only an artifact of slide preparation. In this study, we evaluated whether the smudge cell percentage on a blood smear predicted survival of CLL patients.
  
  
  METHODS
  We calculated smudge cell percentages (ratio of smudged to intact cells plus smudged lymphocytes) on archived blood smears from a cohort of previously untreated patients with predominantly early-stage CLL enrolled onto a prospective observational study. The relationship between percentage of smudge cells, patient survival, and other prognostic factors was explored.
  
  
  RESULTS
  Between 1994 and 2002, 108 patients were enrolled onto the study and had archived blood smears available for review; 80% of patients had Rai stage 0 or I disease. The median smudge cell percentage was 28% (range, 1% to 75%). The percentage of smudge cells was lower in CD38(+) versus CD38(-) patients (P = .019) and in Zap70-positive versus Zap70-negative patients (P = .028). Smudge cell percentage as a continuous variable was associated with prolonged survival (P = .042). The 10-year survival rate was 50% for patients with 30% or less smudge cells compared with 80% for patients with more than 30% of smudge cells (P = .015). In multivariate analysis, the percentage of smudge cells was an independent predictor of overall survival.
  
  
  CONCLUSIONS
  Percentage of smudge cells on blood smear is readily available and an independent factor predicting overall survival in CLL.
authors.affiliation: Department of Internal Medicine, Division of Hematology, Mayo Clinic, Rochester, MN 55905, USA. Nowakowski.Grzegorz@mayo.edu
authors.forename: Grzegorz S
authors.initials: GS
authors.lastname: Nowakowski
authors.forename: James D
authors.initials: JD
authors.lastname: Hoyer
authors.forename: Tait D
authors.initials: TD
authors.lastname: Shanafelt
authors.forename: Clive S
authors.initials: CS
authors.lastname: Zent
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Call
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Bone
authors.forename: Betsy
authors.initials: B
authors.lastname: Laplant
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Dewald
authors.forename: Renee C
authors.initials: RC
authors.lastname: Tschumper
authors.forename: Diane F
authors.initials: DF
authors.lastname: Jelinek
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Witzig
authors.forename: Neil E
authors.initials: NE
authors.lastname: Kay
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000473:pathology*; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000473:pathology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis