Patient Safety and Quality

Up to 12 percent of tissues examined by pathologists for cancer result in diagnosis errors

A study supported by the Agency for Healthcare Research and Quality (HS13321) concludes that up to 12 percent of tissues examined by pathologists for cancer result in cancer diagnosis errors. These diagnostic errors can lead to incorrect patient management plans, including delays in cancer treatment. It is not clear whether pathology errors are due to misinterpretation of the sample or poor clinical sampling of the tissues, notes Stephen S. Raab, M.D., of the University of Pittsburgh School of Medicine.

Dr. Raab and colleagues retrospectively examined pathology errors in patients at four hospitals over a 1-year period who underwent pathology tests to determine the presence or absence of cancer or precancerous lesions. They compared pathology reports for same-site cell and tissue specimens for each patient, and a diagnostic error was deemed to have occurred if, for example, a patient's bronchial brush specimen was diagnosed as benign, but the lung biopsy specimen was diagnosed as non-small cell carcinoma. Cancer diagnosis errors were dependent on the hospital, and ranged from approximately 2 to 10 percent of gynecologic cases and from approximately 5 to 12 percent of nongynecologic cases at various hospitals. Errors due to pathologic misinterpretation ranged from 5 to 51 percent, and the remaining errors were due to clinical sampling problems.

Overall, 45 percent of gynecologic pathology errors and 39 percent of nongynecologic errors were associated with harm. Using the number of errors calculated in the study, the researchers estimated that 127,950 patients per year in the U.S. will suffer harm as a result of errors in the diagnosis of cancer in gynecologic and nongynecologic specimens.

More details are in "Clinical impact and frequency of anatomic pathology errors in cancer diagnoses," by Dr. Raab, Dana Marie Grzybicki, M.D., Ph.D., Janine E. Janosky, Ph.D., and others, in the November 15, 2005, Cancer 10-4(10), pp. 2205-2213.

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