The test is under development by Panacea Pharmaceuticals, Gaithersburg, Md. It detects a recently discovered protein called HAAH. People with at least 20 different kinds of cancer -- including lung cancer -- have much higher than normal HAAH levels in their blood.
The test does not prove that a person has cancer. But it does identify people who need additional, more definitive tests, says Panacea research scientist Mark Semenuk.
"The important thing is that we can pick up even stage I lung cancer," Semenuk tells WebMD. "To diagnose lung cancer really early provides the opportunity for curative treatment. Unfortunately, lung cancer does not cause symptoms until fairly late in the disease process."
Semenuk presented studies of the new lung cancer test to this week's American Association for Cancer Research second international conference on Molecular Diagnostics in Cancer Therapeutic Development, held Sept. 17-20 in Atlanta.
In their first study, Semenuk and colleagues obtained 160 blood samples from 160 patients at all four stages of lung cancer and from 93 people who did not have lung cancer.
The HAAH test was positive in 99% of the lung cancer samples but was nearly undetectable in people without cancer. This study allowed the researchers to set an HAAH cutoff level -- 3 ng/mL (nanograms/milliliter) -- that maximizes the number of cancers detected while minimizing the number of false-positive test results.
In a second study, the researchers tested how well the HAAH test could tell people with various stages of lung cancer from smokers without lung cancer. Previous blood tests for lung cancer have been unable to differentiate smokers -- who are at very high risk of lung cancer -- from patients with early-stage lung cancer.
The result: Average HAAH levels were about the same for patients at all four stages of lung cancer, ranging from 16 ng/mL to 22 ng/mL. Average HAAH levels for smokers not known to have cancer were zero. However, about 10% of the smokers tested positive for elevated HAAH levels.
"These results are very encouraging, because they point to those patients who are most likely to need further testing," Semenuk says. "Elevated levels of HAAH cannot confirm whether a person has lung cancer, but can be used as a routine screening test for recommending further diagnostic evaluation. That is the way most cancer biomarker tests ... are meant to work, and this may be one of the most effective to date."
Panacea already offers the three versions of the HAAH test: LC Detect for lung cancer, PC Detect for prostate cancer, and TK Sense to test whether patients with chronic myelogenous leukemia respond to the drug Gleevec. Doctors can send specially prepared blood samples to the Panacea laboratory for testing. The cost of the lung cancer and prostate cancer tests is $125. The TK Sense test costs $500.
Semenuk says that the company is working on possible cancer treatments based on HAAH.