PET/CT shows high value in lung cancer staging trial

ABSTRACT: Bicenter German study shows cost and clinical effectiveness of fusion imaging over CT alone.

NEW ORLEANS-An in-depth assessment of PET/CT at two German teaching hospitals has shown the fusion imaging technology improves on CT alone and pays dividends clinically and financially for staging non-small-cell lung cancer.

The research leading to these conclusions was based on evaluations of 205 patients with proven non-small-cell lung cancer who were staged with FDGPET/ CT and conventional contrast-enhanced imaging with only the CT component of the hybrid scanner. Follow-up was performed five years after staging to assess survival and clinical status.

Patients were imaged at the Technical University Munich and University of Ulm, both in Germany. Results were presented at the 2008 SNM meeting by principal investigator Andreas K. Buck, MD, a researcher in the nuclear medicine department at Technical University Munich.

“Cost-effectiveness of PET/CT in lung cancer or other malignancies has not been examined to this extent before,” said Markus Schwaiger, MD, dean of the Technical University Munich and a contributor to the study.

“This is the first study indicating that PET/CT leads to an increase of survival in NSCLC patients due to more precise description of the tumor stage at initial presentation,” Dr. Schwaiger pointed out.

The combined PET/CT approach improved diagnostic accuracy and altered therapy decisions. Study subjects evaluated with PET/CT also survived longer than those who were not examined with fusion imaging technology.

PET/CT was more accurate than CT alone for tumor, nodal, and metastatic staging (see Figures 1-3).

CT alone led to seven false T-stage readings, compared to none for PET/CT. CT alone contributed to 28 false Nstage findings, compared to three for PET/CT, and it found distant metastases in 28% of patients compared to the 35% of patients in whom PET/CT found such metastases.

The PET/CT studies led investigators to downstage 21 patients (10.2%), which, in turn, led to recommendations for 13 additional surgical procedures. Fourteen patients were upstaged, leading to the cancellation of nine surgeries.

The mean survival of patients staged with PET/CT was 957 days, compared with 453 days for patients staged with CT alone.

The improvements in diagnostic accuracy and the changes in therapeutic management with PET/CT were due, in part, to the nature of the two modalities, Dr. Buck said.

PET characterizes tumor cells that are biologically alive and active, whereas CT shows a physical picture of the tumor size and shape. Both are informative, but the combined image gives physicians more information than either technology by itself can.

Cost-effective

In addition to finding measurable clinical benefits for PET/CT, the study also established the cost-eff ectiveness of a fusion-imaging approach for staging nonsmall- cell lung cancer, Dr. Buck said.

“We believe that in the era of evidence- based medicine we cannot stick to diagnostic efficiency but have to address survival advantages for the individual patient and cost efficiency as well,” he said.

The cost of an additional quality-adjusted year of life, including diagnosis and treatment, was assessed at $81,762 (about €52,000), according to the study. This was substantially less than the $147,980 (about €100,000) considered the ceiling for a cost-effective diagnosis, Dr. Buck said.

It cost an average of $4,330 to correctly stage a tumor using PET/CT.

“Demonstration of cost-effectiveness helps to further establish PET/CT as standard for tumor staging, not only for lung cancer, but also for other malignancies,” Dr. Schwaiger said.