What to do about incidental findings: the (less than) 1% solution

September 29, 2010

Pathologies such as infections, or even tumors, crop up from time to time in patients examined for entirely unrelated issues. These “incidental findings” can put doctors-and patients-in a tight spot. How do they proceed with the patient, knowing that many of the asymptomatic signs of disease may never lead to clinical problems, or may simply be false positives?

Pathologies such as infections, or even tumors, crop up from time to time in patients examined for entirely unrelated issues. These “incidental findings” can put doctors-and patients-in a tight spot. How do they proceed with the patient, knowing that many of the asymptomatic signs of disease may never lead to clinical problems, or may simply be false positives?

For those who have run into this situation and chosen the path of less intervention, there is now research evidence that they likely did the right thing.

A paper in the Sept. 27 issue of Archives of Internal Medicine notes that although incidental findings, such as a tumor or infection, are uncovered on radiological exams in up to 40% of research participants, an expert panel determined that clinical action was justified in only 6.2% of the cases. And, of those who received treatment, only a miniscule number actually benefited.

Lead author Dr. Nicholas M. Orme, a resident in the department of general internal medicine at the Mayo Clinic, and colleagues documented incidental findings in 567 of 1426 subjects participating in research during January through March 2004. Each image was interpreted by a radiologist the day it was performed. Just 35 of these 567 subjects ultimately received medical treatment for the incidental finding during a three-year follow-up period. Only six of these 35, less than 1% of all subjects with incidental findings, gained any clear medical benefit from the intervention. Three of the 35 carried a “medical burden” as a result.

The incidental findings noted in the paper were most often found on CT scans of the abdomen and pelvis, followed by CT of the chest, and MRI of the head. The risk of an incidental finding was determined to increase with age. Incidental findings, the authors say, raise the potential for early diagnosis of asymptomatic life-threatening disease, but also invite costly, invasive, and ultimately unnecessary interventions for benign processes.