UCSF Medical Center is offering a screening test for early detection of lung
cancer, a disease that claims about 157,000 lives in the United States each
year—more than breast, prostate and colon cancer combined.
Using spiral computerized tomography (CT) scanning, physicians are able to
detect tiny nodules on the lungs that could be lung cancer in its earliest
stages. This technology may help cut down on the number of lung cancer deaths
by allowing physicians to catch the disease early and surgically remove the
lesions before they grow and spread through the body, said Paul Brunetta, MD,
UCSF assistant professor of pulmonary medicine. Brunetta began offering CT
scans, also called CAT scans, to patients two months ago in the Thoracic
Oncology program at UCSF Medical Center at Mount Zion.
“I think we need to be as hopeful about this technology as we were about
mammography,” Brunetta said. “I think we can identify people at risk for lung
CT scans use X-rays to scan the entire chest in about 15 to 20 seconds during a
single breath hold. The patient lies on a table, passing through an X-ray
machine shaped like a doughnut with a large hole. The machine rotates around
the patient as a computer creates images from the scan. If the radiologist
detects an abnormal looking nodule, he or she recommends the patient receive a
higher resolution scan to see if the small mass has characteristics of cancer.
If the nodule is still potentially malignant, the patient either has a repeat
scan in three months or the mass is biopsied (a section of the tissue is
removed to determine if it is cancer).
Lung cancer is the leading cause of cancer deaths in the United States,
accounting for nearly 28 percent of all cancer deaths, according to the
American Cancer Society. Unlike breast, prostate and other cancers, there are
no tools to diagnose lung cancer early. Usually, 90 percent of all lung cancers
are detected when patients show symptoms of the disease, such as coughing blood
or chest pain. By then, the disease may have spread to other parts of the body,
making it difficult for physicians to save the patient’s life, Brunetta said.
More than 80 percent of all lung cancer cases are related to smoking.
Physicians across the country are debating the effectiveness of using CT scans
for early detection for lung cancer, Brunetta said. CT scans have not been
shown to decrease lung cancer mortality rates. Previous studies have estimated
that of all nodules detected with this technology, just 15 percent are
malignant. What can appear to be the beginnings of a tumor are often harmless
marks on the lungs caused by dust or scars left from other illnesses such as
pneumonia. This raises concerns about the tests creating false/positive results
that can potentially cause patients to undergo unneeded biopsies.
“As long as it hasn’t been proven effective, people say why are you doing
this?” Brunetta said. “It has a high cost and you run the risk of performing
unnecessary biopsies, as would be the case with an abnormal mammogram.”
But Brunetta believes the tests could be an important tool in fighting lung
cancer, which has a five year survival rate of only 13 percent.
“Lung cancer is a very common and deadly disease. The way we treat it now is
dismal,” Brunetta said. “If we are finding that in the majority of patients we
can’t cure the disease, then where does that leave us? The technology is widely
available. It only requires that people hold their breath for 20 seconds. And
it’s not painful or invasive. If we can detect the disease early enough to have
a 90 percent resectability rate (surgically removing the tumor), then I think
it’s worthwhile. We need to study this carefully.”
Brunetta is principal investigator of the Early Lung Malignancy Study, which
will examine lung cancer detection rates among high risk individuals using CT
scanning and sputum tests—when phlegm coughed from the patient’s lungs is
inspected for signs of cancer. To enroll, participants must be 60 years or
older and have a 20 pack-year or greater history of cigarette smoking. A pack
year is the number of years someone has smoked multiplied by the number of
packs smoked per day. Someone with a 20 pack year history could have smoked one
pack of cigarettes for 20 years or two packs per day for ten years.
Participants must also have one or more other risk factors, including asbestos
exposure, a family history of cancer, prior obstructive lung disease, prior
lung or head and neck cancer or significant exposure to radioactivity.
CT scans have been used since the 1970s to provide diagnostic information for
many parts of the body, including the brain, blood vessels, heart, liver and
skeletal system. For cancer, CT scanning is used to determine how much a tumor
has grown after the initial diagnosis, according to the National Cancer
Institute. More than half of the hospitals in the United States own a CT
machine. Only recently have some hospitals and practices begun offering CT
scans to patients for early detection of lung cancer.
“We know anecdotally that this can save lives,” said Ron Arenson, MD, UCSF
professor and chairman of the Department of Radiology. “The question is can we
justify the cost of massive screening. Chasing down all of those false
positives can be an enormous expense. But it’s not as much when you compare it
to the cost of taking care of cancer patients.”
Brunetta added: “Early detection of cancer can potentially save lives, as has
been proven with breast cancer,” he said. “This remains unproven, however, with
this promising imaging technique.”
For more information about the scans or the study, call (415) 885-7387.