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  Anatomic Abstracts

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cap today

October 2005

Editors:
Michael Cibull, MD
Subodh Lele, MD
Melissa Kesler, MD

Lack of adherence to practice guidelines for women with atypical glandular cells on cervical cytology
Little or no residual prostate cancer at radical prostatectomy: vanishing cancer or switched specimen?
Significance of field validation in the CAP Interlaboratory Comparison Program in Cervicovaginal Cytology
Patient safety in anatomic pathology: measuring discrepancy frequencies and causes

Lack of adherence to practice guidelines for women with atypical glandular cells on cervical cytology

The authors conducted a study to estimate the rates and types of evaluation of women with atypical glandular cells of undetermined significance on cervical cytology and to assess these findings on the basis of published management guidelines. The rates of histologic sampling, comprehensive initial evaluations, and secondary evaluations were assessed in 477 women with an atypical glandular cells of undetermined significance (AGC-US) Pap test from 1998 to 2001. A comprehensive evaluation was defined as a colposcopy and an endocervical curettage with or without a cervical biopsy. For women aged 35 or older, a comprehensive evaluation also included an endometrial biopsy. A secondary evaluation consisted of a diagnostic cone biopsy. Sixty-four percent of women with an AGC-US Pap test had histologic sampling; 36 percent were followed by repeat Pap test only. Thirty-six percent of women with an AGC-US Pap test had a comprehensive evaluation. Women with an AGC-US Pap test that was subclassified as malignant appearing had higher rates of histologic and comprehensive evaluations than women with a benign-appearing or unspecified AGC-US Pap test (P<.01). Twenty-eight percent of women aged 35 or older had comprehensive evaluations compared with 57 percent of women younger than the age of 35 (P<.01). Secondary evaluations were performed in eight percent of women with persistent AGC-US Pap tests and two percent of women with malignant-appearing AGC-US Pap tests after negative initial histologic evaluations. Twelve of the 42 cases of disease (29 percent) were diagnosed more than one year after the initial AGC-US Pap test. The authors concluded that on the basis of accepted management guidelines, these data suggest that women with AGC-US Pap tests are undermanaged in their initial and secondary evaluations.

Sharpless KE, Schnatz PF, Mandavilli S, et al. Lack of adherence to practice guidelines for women with atypical glandular cells on cervical cytology. Obstet Gynecol. 2005; 105(3): 501–506.

Reprint information not available.

Little or no residual prostate cancer at radical prostatectomy: vanishing cancer or switched specimen?

With more vigilant screening for prostate cancer, there has been an associated increase in patients with little or no residual cancer at radical prostatectomy after an initial diagnosis of minute cancer on needle biopsy. This raises a critical question as to whether the biopsy and subsequent radical prostatectomy are from the same patient. The authors used PCR-based microsatellite marker analysis to perform identity tests in 46 men (35 with minute cancer and 11 with no residual cancer). Of the tests, 41 were interpretable, including 31 with minute cancer and 10 with no residual cancer. All 31 interpretable cases with minute cancer showed a match between the initial biopsy and radical prostatectomy specimens. Nine of the 10 interpretable cases with no residual cancer showed a match and one showed a mismatch. The remaining five cases (four with minute cancer and one with no residual cancer) were considered uninterpretable due to technical problems. The initial biopsy of the mismatched case had high-grade cancer (Gleason score, 4+4=8) measuring 9.6 mm in length with perineural invasion. The authors’ results confirm that most cases of “vanishing cancer” in radical prostatectomy specimens reflect a chance sampling of a minute cancer and not a switch in specimens. However, specimen switch, though rare, can occur, and if there is high-grade or a lot of cancer on the biopsy but no cancer or very minimal cancer in the radical prostatectomy specimen, one should verify patient identity.

Cao D, Hafez M, Berg K, et al. Little or no residual prostate cancer at radical prostatectomy: vanishing cancer or switched specimen? A microsatellite analysis of specimen identity. Am J Surg Pathol. 2005;29:467–473.

Reprints: Dr. Jonathan I. Epstein, Dept. of Pathology, Johns Hopkins Hospital, 401 N. Broadway, Weinberg 2242, Baltimore, MD 21231; jepstein@jhmi.edu

Significance of field validation in the CAP Interlaboratory Comparison Program in Cervicovaginal Cytology

In gynecologic cytology, expert opinion is often used as a gold standard for evaluating new technologies, assessing legal matters, and validating cases for use in educational programs and proficiency testing. However, the reliability of expert opinion alone in selecting slides of a specific cytodiagnosis that can be reproducibly and reliably identified by subsequent reviewers has not been determined. The authors conducted a study to assess the ability of expert opinion to select slides that are validated in subsequent reviews. In the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, each case in every cytodiagnostic category is accepted for circulation only after review by three expert cytopathologists. The percentage of these cases that could not be reliably and reproducibly identified by program participants for each cytodiagnostic category (“Failed field validation”) was determined during the duration of the program from 1989 to 2004. More than 10,000 conventional smears and ThinPrep cases were selected by the expert panel for circulation. Of these slides, 19 percent of conventional smears and 15 percent of ThinPrep specimens failed field validation. Compared with overall slide performance, significantly higher percentages (P<.001) of conventional smears with reference diagnoses of unsatisfactory (51.7 percent), repair (58 percent), or low-grade intraepithelial lesion (31.8 percent) and of ThinPrep specimens with reference diagnoses of unsatisfactory (54.5 percent) and repair (76.9 percent) failed field validation. In contrast, significantly lower percentages of conventional smears with reference diagnoses of squamous cell carcinoma (4.5 percent), high-grade squamous intraepithelial lesion (nine percent), Trichomonas vaginalis infection (11.7 percent), or herpes (9.9 percent), and of ThinPrep specimens with reference diagnoses of adenocarcinoma (5.1 percent), herpes (2.1 percent), and fungal organism consistent with Candida (8.4 percent) failed field validation (P<.001 for all). The authors concluded that between 15 percent and 19 percent of gynecologic cytologic cases that have been selected by expert cytopathologists as good examples of cytodiagnostic abnormalities fail field validation. The proportion of cases failing field validation varies with cytodiagnostic category, but it occurs in all cytodiagnostic entities.

Renshaw AA, Wang E, Mody DR, et al. Measuring the significance of field validation in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology: How good are the experts? Arch Pathol Lab Med. 2005; 129(5): 609–613.

Reprints: Dr. Terence J. Colgan, Suite 600, Pathology & Laboratory Medicine, Mount Sinai Hospital, 600 University Ave., Toronto, Ontario, Canada M5G 1X5; tcolgan@ mtsinai.on.ca

Patient safety in anatomic pathology: measuring discrepancy frequencies and causes

The College of American Pathologists conducted a study to determine the frequency of anatomic pathology discrepancies and the causes of these discrepancies. Seventy-four participants in the CAP’s Q-Probes program self-reported the number of anatomic pathology discrepancies in their laboratories by prospectively performing secondary review (post-sign-out) of 100 surgical pathology or cytology specimens. Reasons for the secondary review included conferences, external review, internal quality assurance policy, and physician request. The frequency of anatomic pathology discrepancy; type of discrepancy—that is, change in margin status, change in diagnosis, change in patient information, or typographic error; effect of discrepancy on patient outcome—that is, no harm, near miss, or harm; and clarity of report were evaluated. The mean and median laboratory discrepancy frequencies were 6.7 percent and 5.1 percent, respectively. Forty-eight percent of all discrepancies were due to a change within the same category of interpretation—for example, one tumor type was changed to another tumor type. Twenty-one percent of all discrepancies were due to change across categories of interpretation—for example, a benign diagnosis was changed to a malignant diagnosis. Although the majority of discrepancies did not affect patient care, 5.3 percent had a moderate or marked effect on patient care. The authors concluded that this study establishes a mean multi-institutional discrepancy frequency (related to secondary review) of 6.7 percent.

Raab SS, Nakhleh RE, Ruby SG. Patient safety in anatomic pathology: measuring discrepancy frequencies and causes. Arch Pathol Lab Med. 2005;129:459–466.

Reprints: Dr. Stephen S. Raab, Dept. of Pathology, University of Pittsburgh, UPMC Shadyside Hospital, 5150 Centre Ave., Pittsburgh, PA 15232; raabss@msx.upmc.edu