Diagnosis Errors Can Harm Patients

A new study reveals that procedures used to obtain and examine tissue for cancer diagnosis are prone to error that often results in harm to patients. The findings are reported in the November 15, 2005, issue of Cancer.

A government-mandated error-detection method that involves the review of patient specimens, when patients have two or more specimens from the same body site, found that up to 12% of reviewed specimen pairs had an erroneous diagnosis. Pathologists failed to agree on the cause of most of these errors. Before this, the cause of errors in cancer diagnosis has not been well studied, due in part to the lack of national standards to detect errors.

Researchers at the University of Pittsburgh School of Medicine (PA, USA) reviewed tissue specimens, pathologists' findings, and medical records from four institutions that diagnose precancerous and cancerous lesions. They also reviewed patient material when the diagnoses differed on multiple tests from the same patient. They found that errors were relatively frequent and institution-dependent. Up to 9% of gynecologic specimen pairs (Pap test and cervical biopsy) contained an error and up to 12% of other specimen pairs contained an error. Institutional differences in error rates are probably related to bias in error reporting.

The majority of errors were a result of suboptimal specimen collection, while the proportion of errors caused by pathologist misinterpretation ranged from 5-50%. When pathologists reviewed specimens from other institutions, they frequently disagreed with the assignment of error cause. A review of medical records showed that gynecologic errors resulted in harm in 45% of cases, while other errors resulted in harm in 39% of cases. Pathologists also disagreed on the severity of harm caused by an error in cancer diagnosis.

According to the researchers, variability in practice impairs the ability to understand error cause. "The standardization and uniform reporting of errors in cancer diagnosis is the first step in improving safety,” concluded the authors.




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