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Blinded review has been endorsed by several cytology and pathology organizations as the most appropriate method for the review of cervicovaginal specimens in the context of litigation. Methods for determining the statistical validity of this method were evaluated.First, the authors calculated the sample size needed to detect various differences in case difficulty or ease of interpretation, in which ease of interpretation is defined as the percentage of the time a case could be identified as abnormal by routine screening. Very easy cases could be identified most reliably, whereas more difficult cases were detected less regularly and less reliably. Using construct sample sizes, the authors calculated the number of abnormal reviews that may be helpful to conclude that the case's difficulty or ease of interpretation was statistically significantly different from another case of a specified difficulty. Finally, they examined the effect of using two separate cutoff parameters to make these distinctions.Depending on the threshold chosen, it was determined that improvements in the statistically meaningful distinctions may be made using 15 or 20 reviews. To distinguish between routine false‐negative cases (ease of detection, 40%) and routine cases (ease of detection, 80%), the thresholds may be set at 5 of 10 reviews (a case that would not be detected regularly and reliably in any given laboratory) and 7 of 10 reviews (defining a case that would be identified regularly and reliably), respectively.The authors provide data that can be used to interpret the results of a blinded review in a statistically appropriate manner. To improve the utility of blinded reviews, the standards are defined explicitly. Cancer (Cancer Cytopathol) 2004. © 2004 American Cancer Society.

Recent studies have shown increased interest in measuring error rates in surgical pathology. We sought to determine how many surgical pathology cases need to be reviewed to show a significant difference from published error rates for review of routine or biopsy cases. Results of 4 series with this type of diagnostic material involving a total of 11,683 cases were reviewed to determine the range of published false-negative, false-positive, typing error, threshold error, and clinically significant error rates. Error rates ranged from 0.00% to 2.36%; clinically significant error rates ranged from 0.34% to 1.19%. Assuming a power of 0.80 and a 1-sided alpha of 0.05, the number of cases needed to be reviewed to show that a laboratory with either twice or one half the published error rate was significantly different from the range of published error rates varied from 3.30 to 50, 158. For clinically significant errors, the number of cases varied from 665 to 5,886. Because the published error rates are low, a relatively large number of cases need to be reviewed and a relatively great difference in error rate needs to exist to show a significant difference in performance in surgical pathology.

The TEL/AML1fusion associated with t(12;21)(p13;q22) is the most common gene rearrangement in childhood leukemia, occurring in approximately 25% of pediatric acute lymphoblastic leukemia (ALL), and is associated with a favorable prognosis. For example, a cohort of pediatric patients with ALL retrospectively analyzed for theTEL/AML1fusion treated on Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols between 1980 to 1991 demonstrated a 100% relapse-free survival in TEL/AML1-positive patients with a median of 8.3 years of follow-up. However, two recent studies analyzing pediatric patients with relapsed ALL have reported the same incidence of the TEL/AML1rearrangement as in patients with newly diagnosed ALL, suggesting that TEL/AML1positivity is not a favorable prognostic indicator. To clarify this apparent discrepancy, 48 pediatric patients treated on Dana-Farber Cancer Institute (DFCI) protocols with ALL at first or second relapse were tested forTEL/AML1using reverse transcriptase-polymerase chain reaction (RT-PCR). The TEL/AML1fusion was identified in only 1 of 32 analyzable relapsed ALL patients, in concordance with our previous reports of improved disease-free survival in TEL/AML1-positive patients. The low frequency of TEL/AML1-positive patients at relapse is significantly different than that reported in other studies. Although there are several potential explanations for the observed differences in TEL/AML1-positive patients at relapse, it is plausible that relapse-free survival in TEL/AML1-positive patients may be changed with different therapeutic approaches. Taken together, these results support the need for prospective analysis of prognosis in TEL/AML1-positive patients.