The PET and the Pendulum

We live in an era in which new medical procedures, diagnostic tests, and treatments are being introduced at a rapid pace. Some important new technologies were widely adopted without rigorous initial outcomes testing, with subsequent reconsideration and reduction in use, as exemplified by the pulmonary artery catheter in critically ill patients (1). Other procedures, such as lung volume reduction surgery for severe chronic obstructive pulmonary disease, underwent careful evaluation relatively early on (after a modern reintroduction in the case of lung volume reduction surgery), which strongly influenced their role in current practice (2). These well-studied procedures must be reexamined in light of newer refinements, such as bronchoscopic lung volume reduction (3).

Somewhere between these extremes is the ongoing evolution of positron emission tomography (PET), which has engendered enormous interest since its introduction into clinical oncology in the late 1980s. This technique has a very wide range of potential applications in diagnosis, staging, guiding biopsies, assessment of response to therapy, and identification of recurrent disease, as reflected in a burgeoning literature. In lung cancer, PET considerations are particularly complex—and promising—because the technique provides information about the primary lesion, mediastinum, and distant metastases.

The stakes in this very common form of cancer are enormous for individual patients, physicians, and a health care system struggling mightily to control costs, because lung cancer staging is the foundation for most treatment decisions. The staging …