Lung ca staging stirs debate about noncontrast imaging

SAN FRANCISCO-The new international standards for lung cancer staging and how they pertain to imaging sent sparks flying during a plenary session at the 2009 World Conference on Lung Cancer.

The point of contention arose after Edward F. Patz, Jr., MD, a thoracic radiologist from Duke University in Durham, N.C., recommended non-contrast thoracic CT for staging. He had advised the physicians in the audience that contrast enhancement is a hotly debated question. That point proved true when John C. Ruckdeschel, MD, director and CEO of the Nevada Cancer Institute in Las Vegas, challenged the recommendation.

“I’m flabbergasted by your recommendation that we do noncontrast CT as the initial staging study,” Dr. Ruckdeschel said. “In 30 years of sitting with surgeons every week, time and again we see these low-bid community CTs that are uncontrasted and worse than a chest x-ray. I am petrified that your (recommendation) will make it out into the community.”

In his defense, Dr. Patz referred to a study performed at Duke to compare blinded readings of staging CT for lung cancer performed with and without contrast.

“Granted that it was in a tertiary care institution with thoracic radiologists doing it on the best equipment, but after 120 patients, our statistician told us to stop because the results were so highly statistically significant,” Dr. Patz said. He added that his group could not find a difference between contrast and non-contrast studies (Radiology 212:56-60, 1999).

In the lecture, Dr. Patz noted that there is little need for a dedicated CT if a PET/CT is performed (and that the PET/CT should be used judiciously). PET/CT has become the modality of choice for staging. Its application obviates dedicated thoracic CT or a nuclear bone scan, he said. However, initial diagnosis is still usually based on chest x-rays as they provide an enormous amount of information for staging the disease, he added.

Dr. Patz praised the International Association for the Study of Lung Cancer (IASLC) officials for undertaking the exhaustive evidence-based effort to modify its TMN staging classification system for lung cancer. Forty-seven databases involving more than 100,000 cases from collaborators around the world were used for staging and outcomes analysis. “What is amazing about this whole effort is that it has been evidenced-based,” he said.