Errors in cancer diagnosis common, often harmful

In a review of patient specimens, errors in cancer diagnosis were seen in up to 11.8 percent of cases, according to a report in the medical journal Cancer. Moreover, in a substantial proportion of cases, the error caused some degree of harm for the patient.

The frequency and clinical impact of pathology errors in cancer diagnosis have not been well characterized, lead author Dr. Stephen S. Raab, from the University of Pittsburgh in Pennsylvania, and colleagues note.

In the present study, the authors evaluated diagnostic errors in patients who were seen at one of four hospitals in 2002 for a cancer work-up.

The frequency of errors varied between hospitals and ranged from 1.79 percent to 9.42 percent for gynecologics cases and from 4.87 percent to 11.8 percent for other cases, the researchers note. A significant link between the institution and the error cause was observed.

As for the cause of errors, up to 50 percent were due to misinterpretation with the remainder being due to poor tissue sampling.

The clinical impact of the error was significantly associated with the institution. On further analysis, it appeared that up to 45 percent of errors resulted in harm to the patient, ranging from further unnecessary diagnostic tests to loss of life or limb.

"It is exceedingly difficult to measure the true frequency of errors in cancer diagnosis because of the variety of detection methods used, bias, and the inability of institutions to secondarily review large case volumes," the authors state.

"As part of a multi-institutional, national effort to improve practice, we are in the process of standardizing methods, decreasing bias by sharing cases and data among institutions, and establishing more accurate error frequencies by detecting errors using multiple methods," they add.

SOURCE: Cancer, November 15, 2005.