TUESDAY, Oct. 15 (HealthDay News) -- Researchers say they've
developed a blood test that can detect some cases of early stage
lung and prostate cancer.
Although the test has limited accuracy and only a small number
of people have tried it, it potentially could provide doctors more
information when they suspect a patient has a tumor.
"[This is] one more tool doctors can use to help guide clinical decisions," said study co-author Dr. Daniel Sessler, professor and chairman of the department of outcomes research at the Cleveland Clinic. "It is also potentially important because the only current routine diagnostic method for lung cancer is CT scanning, which is both expensive and requires radiation exposure."
Researchers have spent a decade or more trying to develop a
blood test to detect cancer, said Dr. Len Lichtenfeld, deputy chief
medical officer of the American Cancer Society. Tests would be
especially useful if they detect cancer in its early stages when
treatment is most effective. Some scientists dream of a test people
could take at home using drops of blood from a finger prick, he
The prostate specific androgen, or PSA, test can detect signs of
prostate cancer, but its usefulness is the subject of much debate
because it is sometimes inaccurate, leading to unnecessary
treatment. A blood test like the one developed for this study could
be a useful addition to prostate cancer screenings, the researchers
For now, studies into cancer tests continue, Lichtenfeld said,
but they remain challenging to develop because signs of cancer in
the blood can be minuscule. "We're getting closer to the
possibility but we're there not there yet," he said.
In the new study, which Lichtenfeld described as "very early"
research, the authors examined blood samples from 95 cancer
patients and compared them to samples from healthy people. They
also examined blood samples from 24 patients before and after they
had surgery for lung cancer.
The researchers found that the cancer patients had up to six
times the level of serum-free fatty acids and their metabolites
(which are produced during metabolism) as the cancer-free
participants. Also, within a day after lung cancer surgery, the
levels of fatty acids decreased by between three and 10 times.
Sessler said the fatty acids are necessary for cancer cells to
grow, and some cancers release them.
The findings were scheduled for presentation Tuesday at the
annual meeting of the American Society of Anesthesiologists in San
How effective is the test itself? Sessler said it correctly
identifies cancer patients 70 percent of the time and patients
without cancer 70 percent of the time.
"It is thus by no means perfect, but may provide information to guide clinicians, especially in high-risk patients," he said.
Sessler said the results could help physicians figure out what
to do about a suspicious-looking nodule. "And it might help
evaluate the response to surgery and whether or not cancer has
recurred," he said.
"Like all tests, there will be both false positives and false negatives," Sessler said. "Using it in the right patients and interpreting the results in context with other clinical data will be necessary."
What about the cost? "The test is nowhere near being commercial,
so cost can't yet be determined," Sessler said.
The next step for the researchers is to keep track of blood test
results after surgery to see if they pick up recurrences of
Data and conclusions presented at meetings typically are
considered preliminary until published in a peer-reviewed medical
For more about
cancer, see the U.S. National Library of Medicine.
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