Positron emission tomography (PET) can save hospitals tens of
thousands of dollars in the evaluation of patients with suspected
lung cancer and provide more accurate disease staging than conventional
imaging tests, according to a report presented at the recent meeting
of the Society of Nuclear Medicine. A multicenter clinical trial
shows that PET scanning can provide crucial information that helps
determine whether solitary pulmonary nodules need to be surgically
removed. By scanning the lung with fluorine-18 [18F]-fluorodeoxyglucose
(FDG), a radiotracer analog of sugar that visualizes metabolic
function, imaging specialists can identify which lesions are malignant
and which are benign.
To measure the accuracy of PET in these circumstances, 89 patients
whose chest x-rays and CT scans showed lung nodules underwent
PET-FDG scanning. Results showed that PET lung scanning with 18F-FDG
has an accuracy of 85% to 90% in differentiating malignant from
benign nodules. Malignant tumors show more radiotracer uptake
of 18F-FDG than benign tumors.
"A negative PET-FDG study can justify a decision not to surgically
remove the nodule in the lung," said
R. Edward Coleman, MD, director of radiology and nuclear medicine
at Duke University. "With the increased accuracy provided
by PET scanning, about 10,000 patients per year in this country
can avoid unnecessary lung surgery." Thoracotomy, according
to the investigators, costs approximately $30,000.
Thus, say the researchers, this clinical trial should convince
more third-party payors and managed care organizations to cover
the costs of PET scanning. In the long run, the health-care system
would save a great deal of money if PET results were used to help
determine which patients should undergo surgery.
Another Study, From UCLA
Cost savings with PET lung studies are also reported by physicians
at the University of California in Los Angeles School of Medicine.
When hospitals add a whole-body PET-FDG scan to the diagnostic
workup of patients with non-small-cell lung cancer, they can save
an average of $204 per patient without reducing overall life expectancy.
The cost savings come primarily from avoiding surgery in patients
whose disease is too far advanced to be successfully removed.
PET can show metastatic spread of lung carcinoma that is missed
by CT and other diagnostic imaging tests, according to the UCLA
"When you multiply that $204 by the estimated 120,000 people
diagnosed in the US each year with non-small-cell lung cancer,
you can see that PET scanning could save about $24.5 million in
nationwide healthcare costs,"said Sanjiv S. Gambhir, MD,
PhD, assistant professor, of molecular and medical pharmacology
at UCLA. In fact, Dr. Gambhir said, further analysis of their
data showed that their assumptions of the accuracy of CT in these
patients were overestimated. "Our revised data indicate that
hospitals can actually save $1,114 per patient when they include
whole-body PET in the diagnostic workup of patients with non-small-cell
lung cancer. By using PET, the annual cost reduction to the US
health-care system could total $133.7 million," Dr. Gambhir
"This estimated savings is based on a clinical decision tree
that shows the probability of a patient having lung cancer based
on results of various diagnostic tests," said Dr. Gambhir.
The decision-tree analysis assumes the following costs for diagnostic
- 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-body
PET scanning with 18F-FDG provided additional information that
changed the stage of disease in 7, or 35%, of patients. Disease
staging was originally based on conventional imaging methods,
such as CT, MRI, and radionuclide bone scanning. In general, physiologic
imaging with PET detects malignancies that are missed by anatomic
imaging methods, such as CT and MRI.
"Cancer is a multiorgan disease," noted I. Madar, PhD,
of UCLA. "Whole-body PET imaging can detect malignancies
throughout the whole body--in both soft tissues and bone--with
one scan that takes about an hour. In current practice, patients
with cancer typically undergo three CT scans (chest, abdomen,
and pelvis), an MRI brain scan, and a radionuclide bone scan to
get the same whole-body information. Besides the extra time and
cost of so many scans, parts of the body can be missed because
often there are anatomic gaps between the chest, abdominal, and
pelvic 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 imaging
methods. "Including PET as a supplement to CT provides information
that helps oncologists plan the most effective strategies for
surgery, radiation therapy, and/or chemotherapy for individual
patients," said Dr. Madar.
In general, lung cancer that has spread to the media- stinum is
considered inoperable. CT has a tendency to show lesions in the
mediastinum that are false-positive. Traditionally, physicians
need to do exploratory surgery to see if the lung cancer has really
spread this far. "However, if the patient has a PET scan
that shows malignancy in the mediastinum, thoracotomy can be avoided,"
said Dr. Madar. "If the PET scan shows no radiotracer uptake
in the mediastinum, there is more hope that the lung cancer can
be surgicaaly removed."