PET Scanning Said to Save Money and Improve Staging of Lung Cancer

November 1, 1995

Positron emission tomography (PET) can save hospitals tens of thousands of dollars in the evaluation of patients with

Positron emission tomography (PET) can save hospitals tens ofthousands of dollars in the evaluation of patients with suspectedlung cancer and provide more accurate disease staging than conventionalimaging tests, according to a report presented at the recent meetingof the Society of Nuclear Medicine. A multicenter clinical trialshows that PET scanning can provide crucial information that helpsdetermine whether solitary pulmonary nodules need to be surgicallyremoved. By scanning the lung with fluorine-18 [18F]-fluorodeoxyglucose(FDG), a radiotracer analog of sugar that visualizes metabolicfunction, imaging specialists can identify which lesions are malignantand which are benign.

To measure the accuracy of PET in these circumstances, 89 patientswhose chest x-rays and CT scans showed lung nodules underwentPET-FDG scanning. Results showed that PET lung scanning with 18F-FDGhas an accuracy of 85% to 90% in differentiating malignant frombenign nodules. Malignant tumors show more radiotracer uptakeof 18F-FDG than benign tumors.

"A negative PET-FDG study can justify a decision not to surgicallyremove the nodule in the lung," said

R. Edward Coleman, MD, director of radiology and nuclear medicineat Duke University. "With the increased accuracy providedby PET scanning, about 10,000 patients per year in this countrycan avoid unnecessary lung surgery." Thoracotomy, accordingto the investigators, costs approximately $30,000.

Thus, say the researchers, this clinical trial should convincemore third-party payors and managed care organizations to coverthe costs of PET scanning. In the long run, the health-care systemwould save a great deal of money if PET results were used to helpdetermine which patients should undergo surgery.

Another Study, From UCLA

Cost savings with PET lung studies are also reported by physiciansat the University of California in Los Angeles School of Medicine.When hospitals add a whole-body PET-FDG scan to the diagnosticworkup of patients with non-small-cell lung cancer, they can savean average of $204 per patient without reducing overall life expectancy.The cost savings come primarily from avoiding surgery in patientswhose disease is too far advanced to be successfully removed.PET can show metastatic spread of lung carcinoma that is missedby CT and other diagnostic imaging tests, according to the UCLAgroup.

"When you multiply that $204 by the estimated 120,000 peoplediagnosed in the US each year with non-small-cell lung cancer,you can see that PET scanning could save about $24.5 million innationwide healthcare costs,"said Sanjiv S. Gambhir, MD,PhD, assistant professor, of molecular and medical pharmacologyat UCLA. In fact, Dr. Gambhir said, further analysis of theirdata showed that their assumptions of the accuracy of CT in thesepatients were overestimated. "Our revised data indicate thathospitals can actually save $1,114 per patient when they includewhole-body PET in the diagnostic workup of patients with non-small-celllung cancer. By using PET, the annual cost reduction to the UShealth-care system could total $133.7 million," Dr. Gambhirsaid.

"This estimated savings is based on a clinical decision treethat shows the probability of a patient having lung cancer basedon results of various diagnostic tests," said Dr. Gambhir.The decision-tree analysis assumes the following costs for diagnostictests:

  • CT, $700;
  • PET, $1,200;
  • Mediastinoscopy, $3,000; and
  • Thoracotomy, $30,000.

In a study of 20 patients with non-small-cell lung cancer, whole-bodyPET scanning with 18F-FDG provided additional information thatchanged the stage of disease in 7, or 35%, of patients. Diseasestaging was originally based on conventional imaging methods,such as CT, MRI, and radionuclide bone scanning. In general, physiologicimaging with PET detects malignancies that are missed by anatomicimaging methods, such as CT and MRI.

"Cancer is a multiorgan disease," noted I. Madar, PhD,of UCLA. "Whole-body PET imaging can detect malignanciesthroughout the whole body--in both soft tissues and bone--withone scan that takes about an hour. In current practice, patientswith cancer typically undergo three CT scans (chest, abdomen,and pelvis), an MRI brain scan, and a radionuclide bone scan toget the same whole-body information. Besides the extra time andcost of so many scans, parts of the body can be missed becauseoften there are anatomic gaps between the chest, abdominal, andpelvic CT scans."

The total cost of disease staging by PET for all 20 patients was$25,000, far less than the $42,406 total for conventional imagingmethods. "Including PET as a supplement to CT provides informationthat helps oncologists plan the most effective strategies forsurgery, radiation therapy, and/or chemotherapy for individualpatients," said Dr. Madar.

In general, lung cancer that has spread to the media- stinum isconsidered inoperable. CT has a tendency to show lesions in themediastinum that are false-positive. Traditionally, physiciansneed to do exploratory surgery to see if the lung cancer has reallyspread this far. "However, if the patient has a PET scanthat shows malignancy in the mediastinum, thoracotomy can be avoided,"said Dr. Madar. "If the PET scan shows no radiotracer uptakein the mediastinum, there is more hope that the lung cancer canbe surgicaaly removed."