Procedures used to obtain and examine tissue for cancer diagnosis areprone to error that frequently results in harm, according to a newstudy published in the November 15, 2005 issue of CANCER (http://www.interscience.wiley.com/cancer-newsroom),a peer-reviewed journal of the American Cancer Society. Agency forHealthcare Research and Quality-funded researchers say that agovernmentally mandated error detection method that involves the reviewof patient specimens, when patients have two or more specimens from thesame body site, found up to 12 percent of reviewed specimen pairs hadan erroneous diagnosis. However, pathologists failed to agree on thecause of most of these errors.
The frequency and cause of errors in cancer diagnosis has not beenwell studied partly because of the lack of national standards to detecterrors. To characterize the frequency, cause, and impact of errors incancer diagnosis, Stephen S. Raab, M.D. of the University of PittsburghSchool of Medicine and colleagues reviewed tissue specimens,pathologists' findings, and medical records from four institutions thatdiagnose precancerous and cancerous lesions. Patients often havemultiple tests in order to diagnose cancer, and the researchersreviewed patient material when the diagnoses differed on multiple testsfrom the same patient.
They found that errors were relatively frequent andinstitution-dependent. Up to 9 percent of gynecologic specimen pairs(Pap test and cervical biopsy) contained an error and up to 12 percentof non-gynecologic specimen pairs contained an error. Differences ininstitutional error rates are most likely related to bias in errorreporting, although underlying quality improvement methods may haveresulted in lower error frequencies at some institutions.
The majority of errors were a result of sub-optimal specimencollection, and the proportion of errors caused by pathologistmisinterpretation ranged from 5 percent to 50 percent. Whenpathologists reviewed specimens from other institutions they frequentlydisagreed with the assignment of error cause.
Review of medical records showed that gynecologic errorsresulted in harm in 45 percent of cases and non-gynecologic errorsresulted in harm in 39 percent of cases. Harm most likely consisted indelays in diagnosis and additional testing that drove up healthcarecosts. It is very rare that unneeded procedures are performed for thefalse positive diagnosis of cancer. Pathologists also disagreed on theseverity of harm that was caused by an error in cancer diagnosis.
The researchers say that their study demonstrates not only arelatively high frequency of error using this detection method, butthat variability in practice impairs the ability to understand errorcause. To that end, "the standardization and uniform reporting oferrors in cancer diagnosis is a first step in improving safety,"conclude the authors.
Article: "Clinical Impact and Frequency of Anatomic Pathology Errorsin Cancer Diagnoses," Stephen S. Raab, Dana Marie Grzybicki, Janine E.Janosky, Richard J. Zarbo, Frederick A. Meier, Chris Jensen, andStanley J. Geyer, CANCER; Published Online: Monday, October 10, 2005(DOI: 10.1002/cncr.21431); Print Issue Date: November 15, 2005.
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