Aug 172012

(image: Wikipedia)

As one after another specialty society endorses routine lung cancer screening with chest CT scans, we all know a Nodule Storm is coming to a pulmonology clinic near you. Thankfully, smart people are asking how we can systematically and successfully handle this soon-to-be-common outpatient clinical problem.

Most of these many thousands of nodules will be false-positive (not cancer), so procedural risk is to be avoided. By that standard, transthoracic needle biopsies' ~15% pneumothorax rate is a little concerning. Traditional transbronchial biopsies are so 1974, and they don't usually give a diagnosis for any but the biggest pulmonary nodules (i.e., masses). Fortunately(?), the past 15 years or so have brought a dizzying array of new whiz-bang bronchoscopic technologies to the interventional-minded pulmonologist's arsenal -- for those who can afford the capital expense, of course. These include electromagnetic navigation bronchoscopy (ENB), virtual bronchoscopy (VB), radial endobronchial ultrasound (R-EBUS), the ultrathin bronchoscope, and guide sheath bronchoscopy.

Advanced bronchoscopy proponents will golf-clap the work of Jessica Wang Memoli, Paul Nietert and Gerard Silvestri of the Medical Univ. of South Carolina, who searched MEDLINE for all the studies using any of these technologies -- a total of 39 studies including 3,052 pulmonary nodules -- and found a pooled diagnostic yield of 70%. Unsurprisingly, the yield went up as the nodules got bigger: nodules less than 2 cm were diagnosed 60% of the time (compared to ~35% with traditional transbronchial biopsy); nodules > 2 cm were diagnosed 83% of the time.

Perhaps most persuasive for advocates of the new technologies, the pneumothorax rate was only 1.5% (in the 28 studies reporting adverse events). By contrast, the reported yields for transthoracic needle biopsy have been higher -- up to 90% in some series -- but with that pesky 15% pneumothorax risk.

Publication bias should be assumed. The people who suck at doing these procedures are unlikely to publish their case series telling us so.

The expense associated with these gadgets (the last rumored price tag I heard for a superDimension system exceeded $1 million, although the others are cheaper) and the superior yields of transthoracic needle biopsy, combined with the fact that thousands of interventional radiologists can do TTNB, but only a handful of trained advanced bronchoscopists can reach peripheral nodules, mean that the new technologies are unlikely to proliferate very far, very fast.

But when the Nodule Storm hits, those centers who have chosen to invest in the new toys and the personnel to play with them might be better able to compete for patients -- especially if (when) pneumothoraces after TTNB in the community start to make the news. (I knew there must have been a reason why Covidien paid $300 million to buy superDimension, the super-wow 3-D navigational bronchoscopy company.)

Memoli JSW et al. Meta-analysis of Guided Bronchoscopy for the Evaluation of the Pulmonary Nodule. Chest 2012; 142:385-393.

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Advanced bronchoscopy yields are 70% in meta-analysis (Review)