An evaluation of a Pennsylvania-based academic community hospital has revealed that radiologists don’t always adhere to guidelines regarding the incidental finding of solitary pulmonary nodules on CT, often resulting in overmanagement, according to a study published in the May issue of the Journal of the American College of Radiology.

Solitary pulmonary nodules are a common incidental finding on CT, according to study authors Mark Masciocchi, MD; Brent Wagner, MD; and Benjamin Lloyd, MD, all from Reading Hospital and Medical Center in West Reading, Penn. Choosing the most appropriate management of the nodule often requires walking a fine line between early diagnosis and unnecessary follow-up.

“Overmanagement by radiologists could lead to increased cost, radiation exposure and patient anxiety. Conversely, undermanagement could subject a patient to the risk of missing a malignancy while it is still curable,” wrote the authors.

The Fleischner Society created evidence-based guidelines in 2005 to help clinicians with this dilemma. Fleischner criteria are designed to stratify risk for malignancy based on nodule size and patient history. Masciocchi and colleagues wanted to evaluate how closely Reading Hospital radiologists adhered to these criteria.

A data set of 3,000 CT scans with the word nodule from 2008 to 2010 was generated and eventually culled to 1,432 exams based on exclusion criteria. Adherence rates of radiologists were tracked across four consecutive exams in the management of a solitary pulmonary nodule.

Results showed that adherence was lowest at the second consecutive study—usually the first follow-up—but increased in later examinations. Specifically, adherence rates in four consecutive CT exams were 57, 48, 70 and 79 percent, respectively. The authors explained the increasing rates in the third and fourth exams were likely due to evidence of stability in the nodule.

“Although radiologists may differ on how early they recommend follow-up, the conventional wisdom continues to be that a nodule stable for two years is most likely benign. As a nodule approaches this milestone, this likely creates confidence in benignity,” wrote the authors.

As to why the second exam, rather than the first, had the lowest adherence, the authors speculated that nodules could be considered benign at first identification based on size or other characteristics, leaving only more suspicious nodules for the second exam.

Of the reasons for nonadherence, overmanagement was the most common deviation from the Fleischner criteria, occurring in 15 to 28 percent of reports evaluated in the study.

The authors noted that while evaluation of adherence rates seemed to be an objective process, the nature of the Fleischner criteria left plenty of room for individual clinician interpretation. For instance, the criteria don’t detail many of the clinical contexts in which the guidelines should apply, offering only three common scenarios on which to base decisions upon. The guidelines also do not address some characteristics of pulmonary nodules that could influence management decisions, such as ground-glass characteristics indicating a slow-growing nodule.

Masciocchi concluded by stressing that while radiologists at their organization often made recommendations which were adherent to the Fleischner criteria, it is up to the referring clinician to follow these recommendations. “Ultimately, clinicians look to our radiologists for their recommendations for follow-up. Improvement in our adherence is the first step in improving patient care,” wrote the authors.