What to Do About Accidentally Finding Cancer

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Cancer is a tough word to hear as a patient, and “mass” (my physician way of hedging my bet until I have proof) isn’t much better. As our ability to detect cancer improves, another troublesome phrase has entered the lexicon, "slow-growing, indolent cancer" – one that can be observed rather than treated. A paper in JAMA looks at the increasing discovery and ensuing predicament of these incidental tumors.

With the advent of sophisticated imaging, CT and MRI, doctors and patients are increasingly confronted not by diseases they were searching for, but by incidental findings, frequently masses that needed further evaluation and possible treatment. The authors looked at incidental findings of masses within the kidney because they are a frequent incidental finding, and a growing literature describes a range of behavior by kidney or renal cancers, from indolent to aggressive. The primary treatment for such cancers was the removal of part or all of the kidney and more recently a less invasive means of killing off the section of the kidney containing cancer (ablation). They chose renal cell cancers and nephrectomy (the surgical removal of the kidney) because studies have demonstrated a rising detection of renal cancers and a stable mortality rate - outcomes have been unchanged despite earlier identification. It is an important model because kidney cancer ranging behavior is also seen in breast, prostate and thyroid cancers.

Using the Medicare dataset, they looked at a 5-year period, for all 65 to 85-year-old individuals in traditional Medicare, about 15.5 million patients. Their analysis used hospital referral regions, a definition that helps cluster patients based on where they get their care. Forty-three percent of patients had a CT during the study period that imaged their kidneys. This percentage varied by referral regions from 31% to 52%. As you might expect, the more imaging, the more incidental finding of a kidney mass and subsequently more treatment. After controlling for smoking, because it may increase the risk of renal cancer and is a confounding effect, they noted that for every 1000 CTs 4 patients underwent partial and complete removal of their kidney. When they included the less invasive means of treating these tumors, the overall impact was 5.5 patients/1000 CTs. The finding is simple, more scans, more detection, more treatment.

But it is the clinical context, the concerns of you and me that are problematic. Autopsy data shows a 1-2% incidence of unsuspected kidney cancers, CT is far more sensitive and may detect an even higher percentage. Among these incidental cancers, small (<4cm) tumors grow slowly, and active observation, which includes frequent re-imaging and physician follow-up, seems to be as good a course as active treatment, removing or destroying the cancer. We may be overtreating these patients, and the treatments themselves have consequences, including increased complications and death. What should we do?

This paper cites a small study of 497 patients with these small, slow-growing renal cancers, allowing them to choose between removal or observation. Fifty-five percent selected removal, 45% observation with 9% of those patients undergoing surgery later in the study. The mortality, due to renal cancer, for the two groups was essentially identical at 5 years, 0%. Death from any cause was higher in the observation group, but this was likely related to their higher incidence of other medical conditions.  

The authors recommend that surgeons confronted with these problems should include active observation, with its small risk of unattended metastasis, among the treatment options; and that patients should give observation real consideration. That is what the numbers, the evidence-based medicine tell us. But in providing the best care, my counsel is evidence-informed, tailored to the needs of my patients. Needs that I perceive and that they express. It is challenging to be told you have cancer and that doing nothing is as good as doing something. Our increasingly sophisticated and sensitive ways of detecting disease make these uncomfortable conversations and uneasy decisions more frequent. Here is how the authors end their study:

We should emphasize that surgeons are not purposely performing unnecessary surgery any more than radiologists are purposely engaged in overdiagnosis [finding those incidental masses]. Many clinicians understand the downsides of incidental detection. Nevertheless, they are caught in a complex web of forces promoting earlier cancer diagnosis and earlier intervention; strong financial interests, fear of litigation, and unquestioning belief among the public about the value of early diagnosis and treatment. More balanced medical care will require addressing these forces.

Guidelines and policy are helpful, but they are not replacements for the relationship and communication between physicians and their patients.


Source: Regional Variation of Computed Tomographic Imaging in the United States and the Risk of Nephrectomy  JAMA Intern Med. Published online December 26, 2017. doi:10.1001/jamainternmed.2017.7508