The $16.7 million x-ray: Possible beats probable in court

In a recent verdict a jury in Massachusetts awarded $16.7 million in damages to the daughter of a Bostonian lady who died from lung cancer at 47, for a missed cancer on a chest x-ray.

The verdict reminds one of the words of John Bradford, the heretic, who was burnt at the stakes. “There but for the grace of God go I.”

Many radiologists will sympathize with both the patient who died prematurely, and the radiologist who missed a 15mm nodule on her chest x-ray when she presented with cough to the emergency department few months earlier.

The damages are instructive of the degree of tension between Affordable Care Act’s push for both resource stewardship and patient-centeredness. But the verdict mostly speaks of the ineffectualness of evidence-based medicine (EBM) in court.

EBM tells us that had the patient’s cancer been detected thirteen months before it actually was, it would have made little difference to her survival. Statistically speaking, that is.

Researchers from Mayo Clinic examining the impact of frequent chest x-rays in screening for lung cancer in a large number of smokers found that the intensively screened group knew about their cancers earlier, had more cancers removed, but did not live longer as a result.

This is known as lead time bias, where early detection means more time knowing that one has the cancer, not more time one is actually alive.

Meaning that had the nodule been seen on the patient’s initial chest x-ray she would probably, not certainly, not have survived much beyond 47.

Lead time bias is a basic concept in epidemiology and biostatistics. Physicians have it drilled in to them. Recognition of this artifact curbs therapeutic and screening optimism.

Why does lead time bias not cross the courtroom door?

Plaintiff’s lawyer need entertain only a possibility that early detection could have cured the cancer to prevail in a suit. Though cure in this case was statistically improbable it was certainly not impossible. Statistics predict, they don’t prophesize.

Evidence-based medicine speaks of the probable. Plural of possibility is not evidence. But possibility beats probability in court. Or, as a defense attorney for medical malpractice confided, “The last thing I want is to call the plaintiff a statistic. That’s a guaranteed turn off for the jury.”

Physicians are increasingly asked to be mindful of the population, not just the individual patient. The explicit message from policy makers is that we must be sensitive of limited resources. We are chastised for overutilization of imaging. Yet it’s hard to see how excess utilization can be curbed unless courts respect evidence-based medicine.

It’s times like this that meaningful tort reform appears painfully conspicuous by its absence from the Affordable Care Act.

One might counter that had the radiologist picked up the lung nodule the lawsuit would never have occurred. That a miss is a miss, regardless of the outcome.

Alas, that, too, is not so simple. Perceptual errors are common in interpreting chest x-rays. Researchers have found that a large number of cancers can be seen, in hindsight, on chest x-rays. So much so, that an appeals court once proffered that a perceptual error is not necessarily negligence.

This case reminds me of the wisdom of one of my professors during residency.  A leading radiologist of his time, he cautioned that “the first ten thousand chest x-rays are easy.”

Puzzled then, but having now interpreted well over ten thousand chest x-rays, I understand what he meant. I am more aware than before of what I might miss. This has created an odd combination of expertise and insecurity.

When the insecurity gets the better of me I imagine shadows on x-rays, and recommend CT scans to “rule out a mass.” Sometimes I catch a cancer. But more often than not I raise false alarms, inconveniencing the patient and wasting resources.

Option traders can avoid trades that are low on the upside and high on the downside. Radiologists do not have that luxury. Paid barely $10 for a chest x-ray, but with a multi-million dollar bounty for missing cancer and a Russian roulette for perceptual errors, radiologists will simply recommend more CAT scans rather than take the risk in declaring that the X-ray is “normal.”

The net cost of this verdict to society will likely be in excess of $16.7 million.

Saurabh Jha is a radiologist and can be reached on Twitter @RogueRad

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