A diagnosis of breast cancer is devastating; however, a wrong diagnosis can be more devastating. Unfortunately, misdiagnosis can occur; a patient with breast cancer will be told she does not have cancer, and a patient who does not have breast cancer can be told that she does have it. Obviously, either of these errors can cause significant harm to a patient. Fortunately, a diagnostic service is available that can reduce diagnostic errors: know error®. To obtain the facts regarding diagnostic errors, I consulted with Dr. David Brousseau, director of Radiology of Los Angeles Center for Women’s Health and Laura Beggrow, president of Strand Diagnostics/Know Error. The accompanying slide show explains how diagnostic errors can occur.
The know error system uses bar coding, forensic principles, and DNA matching to confirm that surgical biopsy samples being evaluated belong exclusively to the patient being diagnosed. (Forensic principles are the use of science or technology in the investigation and establishment of facts or evidence.) The know error system for breast biopsies is in use in medical practices across the nation. Since the test was launched in September 2012 nearly 13,000 breast cancer patients have been tested using the know error system. (The know error test was first launched in prostate cancer in 2010. From 2010- September 2013- over 106,000 prostate cancer patients have been tested)
The cost of medical services is of major importance to most Americans. The good news is that the know error system kits are provided to physicians practices at no charge to the patient nor practice. Ms. Beggrow told me that the patient’s insurance company is billed for the molecular diagnostic testing performed. Reimbursement varies and currently averages around $400 per patient. Strand Diagnostics makes testing available to all appropriate breast cancer patients regardless of their insurance, providing comprehensive assistance and support for all patients throughout the reimbursement process. The know error system is a DNA Specimen Provenance Assignment (DSPA) molecular diagnostic test billed to governmental and commercial insurance providers. Therefore, patients will only be responsible for the in-network deductible, co-insurance, and co-pay amounts applied by their carriers.
Ms. Beggrow told me that they are discovering diagnostic errors in 1.18% of the breast patients that they test. Whether or not the patient received a false positive diagnosis is a function of the diagnosis of the "complementary" tissue. That is, if a patient DOES have breast cancer and her tissue is switched with someone that ALSO has breast cancer, then by chance, neither patient will receive a false reading of cancer. (Although the grade and volume of cancer may have been different, neither would have received a false cancer diagnosis.) The bottom line is that know error can reduce that approximately 1% chance of error to zero.
I asked Dr. Brousseau how often diagnostic errors occurred and if they were increasing. He told me that Specimen Provenance Complications (SPCs) can occur as a result of human error during any step in the complex biopsy diagnostic testing cycle. Some examples of SPCs include mislabeling, specimen transposition, and foreign cell contamination. Approximately 3.5% of cases receiving a positive cancer diagnosis are subject to undetected SPCs, which could lead to a cancer diagnosis being assigned to the wrong patient. Conversely this could lead to a delay in women with breast cancer receiving their diagnosis, potentially delaying life-saving treatment.
The Centers for Disease Control and Prevention (CDC) estimates that more than 200,000 women are diagnosed with breast cancer annually in the United States, meaning approximately 2,000 women per year could be incorrectly diagnosed with breast cancer. Since the issue continues to be undetected and under-reported that number will continue to increase. The error rate provided only includes healthy patients who are diagnosed with cancer; however, it does not include those who are told they do not have cancer but later on do in fact receive a positive biopsy result. These mistakes can set in motion the overtreatment of thousands of patients annually as well as delay the potentially life-saving treatments of women with cancer.
Dr. Brousseau noted that the attention to detail, particularly with respect to specimen labeling, varies widely among medical institutions. At his institution, the Los Angeles Center for Women’s Health, specimens are processed and labeled immediately. He stressed that avoiding batch processing at the point of acquisition is important for patient safety. Nonetheless, many if not most, institutions now utilize third party services to process the specimens before they are reviewed for diagnosis. Since this part of the process is beyond their direct control, they feel very comfortable with the knowledge that the know error system helps them avoid any transposition issues which could potentially occur in subsequent processing. Fortunately, they have not discovered any mislabeling or transposition errors since we began using this system about nine months ago.
Dr. Brousseau told me that issues of cross-contamination are becoming of greater concern to the medical community as tissue specimens undergo more frequent gene testing to predict prognosis and gene testing is employed in decision-making about the use of chemotherapeutic agents. Although cross-contamination itself may not lead to a cancer diagnosis in the wrong patient, it could have a significant effect on a choice about the subsequent treatment. In summary, he said, “Patients that hear those dreaded words - you have breast cancer - and how many are actually getting the wrong diagnosis. Now, with the help of a DNA test, physicians around the Country are aiming to lower the rate at which these errors occur.”
At nearly every step of the 20-step biopsy diagnostic process there is room for mix-ups to hide, undetected. This can be caused by two errors: (1) the patient's sample is switched with another's and (2) the patients sample is contaminated with one or more patient's DNA tissue. Over 200,000 woman are diagnosed with breast cancer per year. This means that treatment recommendations (including removal of healthy breasts and prostates, chemotherapy, radiation) are being made for cancer-free patients and life-saving treatment is being delayed in some cases as well.
Now, when a patient comes into the physician’s office to have a surgical biopsy- where the physician takes a sample of the mass in the breast - they are also given a DNA test (know error system) via cheek swab. When the biopsy sample comes back to the lab and tests positive for cancer, it is then sent to the lab and the DNA from the cheek swab is matched with the DNA from the biopsy sample. From here, it can be determined if the biopsy sample is in fact that patients. This test is a simple, non-invasive way to reassure the patient their diagnosis is their own and, if they do have cancer, then they are receiving the accurate treatment.
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