Cancer Biopsy Mix-ups Are More Common Than You Think

It’s no secret that biopsies occasionally produce inaccurate results. But what if the biopsy result you get is ­accurate—but the tissue sample came from someone else’s body?

Yes, it happens. A study of more than 13,000 prostate biopsies found that switched or contaminated samples caused the wrong patient to be told he had cancer approximately three times in 1,000. Additionally, three times in 1,000, a patient is told he doesn’t have cancer when in fact he does. And there’s no reason to assume that such mix-ups are limited to prostate biopsies.

Lab mix-ups such as these can have catastrophic consequences. A healthy person might be subjected to life-­altering treatments, including surgery, chemotherapy and/or radiation, for someone else’s medical problem. Meanwhile, the person who actually has this major medical problem might be told that he is fine, delaying potentially lifesaving treatments.

What to do: When the stakes of a ­biopsy are high, ask your doctor, “Does it make sense to do a DNA test to confirm that the tissue that was tested originated from me?” Some private labs that do DNA testing for criminal investigations also test to make sure that biopsied tissue samples truly came from the patients who received the results. This type of DNA test typically is covered by health insurance—contact your insurance provider for details. If not, expect it to cost several hundred dollars. Example: Strand Diagnostics, a reputable DNA-testing lab that is accredited by the FBI and CLIA, charges $295 (KnowError.com).­

A doctor might reasonably tell a patient that it does not make sense to do this DNA test if the biopsy result is consistent with other symptoms, such as an MRI scan that shows a large mass. Testing could be worthwhile, however, when there are no other symptoms and/or when the treatment varies dramatically depending on the “grade” and/or precise location of a tumor, as is the case with prostate cancer, breast cancer, colon cancer and other cancers.