How Common Is Cancer Misdiagnosis?

Through decades of practice, our cancer misdiagnosis attorneys have come across numerous studies that confirm a fundamental, and distressing, truth, one we have encountered all too often in our own practical experience. Cancer misdiagnosis is extremely common, as researchers have recently highlighted. We often rely on this research in building our medical malpractice cases, and feel it provides an unprecedented view on what is certainly a major problem.

We also understand that statistics make some people feel uncomfortable. We have no intention of marginalizing anyone’s personal experience by portraying cancer as a disease that can be accurately depicted through numbers alone.

Our attorneys make every effort to treat our clients and their loved ones as individuals. If you don’t want to read statistics on cancer misdiagnosis, you can return to our home page. Moreover, using statistics may be the wrong way to approach an issue like misdiagnosis.

What Can We Learn From Cancer Misdiagnosis Statistics?

Cancer misdiagnosis is primarily a problem of individuals, isolated practitioners and unique patients making life-altering decisions within an increasingly fractured health care system. Marty Makary, professor of surgery and health policy at the Johns Hopkins School of Medicine, has written eloquently on how endemic failings in our health care system often keep patients away from the advancing innovations that could save their lives. “State-of-the-art care” is real, Makary write for CNN, but “delivering it can be messy.”

Surgeons During Operation

These systems, however, are not simply technological or bureaucratic. While the problem is in part driven by insurers and health care policy makers, the vast majority of misdiagnoses come down to specific doctors who fail to appropriately address the threat of cancer, and often forfeit their patients’ lives in the process. From this perspective, statistics may seem futile. How could a bulk, numerical approach help us understand those in-the-moment decisions that threaten the welfare of individuals?

Statistics On Cancer Misdiagnosis Are Scarce

It turns out that cancer misdiagnosis statistics are, in and of themselves, problematic.

There’s not much research out there. Case reports, in which doctors painstakingly recount the details surrounding isolated patients, abound. We can learn a lot from these accounts, but grappling with the overall picture is far more difficult. There is, in particular, a lack of comprehensive research on cancer misdiagnosis within the American context, in our specific, and uniquely-structured health care system.

While a lack of adequate research isn’t proof that the medical community doesn’t take misdiagnosis seriously, it could suggest that academics underestimate how big the problem is.

1. Estimates vary on how often diagnostic errors occur.

Some studies have suggested relatively low incidences, on the order of around 5% of all outpatient visits, while other researchers have found much higher rates, up to 28% in an oft-cited paper from the British Medical Journal. Importantly, many studies that seek to understand misdiagnosis in general use cancer misdiagnosis as the standard for a serious condition.

Cancer Misdiagnosis Statistics Infographic

In 2012, three researchers in Texas estimated that a little over 5% of outpatient visits to the doctor result in diagnostic error. Using estimates for how often US residents go to the doctor, they suggested that approximately 12 million adults are misdiagnosed every year.

Published on April 17, 2014 in the British Medical Journal, the study looked at three earlier studies, all of which focused on cases of cancer. They used computer algorithms to scour patient reports for unusual patterns, like multiple return visits related to the same symptoms and failures to follow-up on test results that the computer flagged as troubling.

While the authors never equated a diagnostic error with negligence, it’s telling to note their definition of misdiagnosis: “missed opportunities to make a timely or correct diagnosis based on available evidence.” In other words, the evidence suggesting a proper diagnosis was there, but physicians evaluated it incorrectly.

Other estimates put that 5% in doubt and suggest, if anything, it’s on the low end. Reviewing a wealth of evidence from the last few decades, the Journal of the American Medical Association placed the incidence much higher, between 10% and 20%.

Whether you choose 10% or 20%, misdiagnosis outweighs both drug errors and botched surgeries as an avoidable cause of patient harm.

Those studies looked at the rate of misdiagnosis from the point of first contact with a medical professional: a patient’s initial visit with their doctor. Other research has investigated weaknesses elsewhere in the health care system.

2. Pathologists routinely over- & under-interpret test samples.

Pathologists are specifically trained to distinguish between normal and abnormal cellular growth. Their work, interpreting biopsies, is considered the gold standard for cancer diagnosis. So how often do they make errors?

To find out, researchers at Dartmouth, the University of Vermont and Seattle’s Fred Hutchinson Cancer Research Center took test samples from breast biopsies. Some slides showed evidence of malignancy, others bore signs of pre-cancerous growth and some presented benign tumors. To create a baseline, they had a panel of expert pathologists diagnose the samples; for each biopsy, they arrived at a consensus opinion – essentially, the closest-to-correct diagnosis possible given the tricky nature of interpreting cellular growth.

Then the team invited pathologists from 8 states in the US to look at the samples themselves. To be eligible, a pathologist needed at least one year of experience diagnosing breast cancer, as well as a stated desire to continue doing so. Ultimately, 115 pathologists completed the study.

In cases of invasive breast cancer, the study produced extremely hopeful results: 96% of the pathologists’ diagnoses accorded with the ones provided by the expert panel. But for more nuanced cases, especially ones involving precancerous growth, the pathologists’ interpretations were troublingly inaccurate:

  • 13% of the diagnoses missed a Stage 1 breast cancer
  • 48% of the interpretations failed to note atypia hyperplasia, a common precursor to breast cancer
  • 17% of the diagnoses overinterpreted atypia hyperplasia, ascribing it more severity than required

Those results, published in the March 2015 issue of the Journal of American Medical Association, are the most recent we have. Needless to say, mistakes of this nature can lead to both undertreatment and overtreatment.

3. Doctors don’t seem to realize how big the problem is.

While the prevalence of cancer misdiagnosis is contested, and many studies suggest very different rates, the British Medical Journal study we cited earlier is probably the most frequently accepted measure of the problem. Again, that study found that nearly 1 in 3 of all cancer patients will be initially misdiagnosed.

Cancer Misdiagnosis Prevalence Infographic

Whether or not real doctors are aware of the problem is another question. In 2013, the National Coalition on Health Care sent a survey to 400 of the nation’s leading cancer specialists. More than 60% of the respondents believed that misdiagnosis rates could be as low as 0%, but certainly no higher than 10%. As NCHC pointed out, that’s far less than the estimates actually available in the medical literature.

4. For every 1 medical malpractice lawsuit, 7.6 patients are injured by doctor error.

In response to widespread claims that medical malpractice lawsuits are totally out of control, and a major cause of rising health care costs, researchers at Harvard decided to actually look into the data.

Cancer Misdiagnosis Lawsuit Statistic Infographic

First, they identified patients who had filed malpractice suits, linking hospital records with Plaintiffs listed on court dockets. Then they took a much wider sample of hospital records and identified all the patients who had suffered some adverse event. Handing those records off to a panel of expert physicians, they figured out which patients had suffered avoidable harm due to a doctor’s mistake. The experts were kept in the dark as to whether or not a particular patient had filed a malpractice claim after the incident.

For a result, the study authors compared the number of malpractice lawsuits to the number of patients who had actually been victimized by malpractice:

  • 98% of the patients who suffered harm due to negligence didn’t file a lawsuit.
  • 7.6 patients suffered the effects of medical malpractice for every 1 patient who filed a lawsuit.

That conclusion gives the lie to the idea that thousands of patients are out there filing meritless claims. If anything, it suggests that a lot of people who deserve compensation aren’t pursuing it, and a lot of doctors aren’t being held accountable for their negligence.

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