Study: on the brink of a new weapon against the deadliest form of cancer
(COLUMBUS, Ohio) – Using just a few drops of blood, researchers have found that they could detect signs of lung cancer in patients two years before their tumors were visible using state-of-the-art body scans.
“What that means is that we may be on the verge of developing a blood test to detect lung cancer in it’s earliest stages” said Dr. Carlo Croce, Director of the Human Cancer Genetics program at Ohio Sate’s James Cancer Hospital.
Croce and his team discovered that molecules in the blood, known as microRNA, develop certain characteristic patterns when lung cancer first begins to form - and long before there are any visible signs of trouble. “The tumor is there, but it’s very small” said Croce, “it cannot be detected by conventional means but can be detected by looking at microRNA.”
The findings could be profound. By the end of the year, another 150,000 Americans will lose their battle against lung cancer.* It is, by far, the deadliest form of cancer in this country, claiming more people each year than breast, colon and prostate cancers combined.*
One of the reasons lung cancer is so deadly, is because it’s often not discovered until the latter stages of the disease. Symptoms may be subtle or non-existent, and by the time patients know something is wrong, it’s often too late.
Right now the most effective way to diagnose lung cancer is by performing what’s known as a spiral CT scan (short for spiral computed tomography scan). The problem is, spiral CT scans are often prescribed only after there are clear signs of trouble. By then, lung cancer is often advanced and, in more serious cases, already spreading to other parts of the body.
But if lung cancer is caught early, the outcome can be much better. “The difference is enormous” said Croce. “If lung cancer is detected very early, the probability of cure, by removing the tumor from the lung of the patient, is very, very high.”
That’s something 54-year old Robin Skinner is banking on. Unlike many lung cancer patients, Robin caught hers fairly early, even though it was purely by accident.
Skinner was experiencing pain in one of her toes and went to see her doctor for what she thought was a case of gout. But her blood work showed something much more dire.
“My doctor drew blood and called me about a week later and said, ‘No, you don’t have gout. You are missing oxygen somewhere in your body.’”
That led to an x-ray that showed a spot on on the upper right side of her chest. “The afternoon of the biopsy they told me that it was cancer, stage 2 lung cancer. They found a spot on my lungs which also was attached to my windpipe” she said. “I wasn’t expecting that. I had no symptoms and, had I not been paying attention to my body, I would never have known I had cancer.”
That’s why the possibility of a blood test to detect lung cancer a much earlier stage is so appealing. For his study, Dr. Croce teamed up with researchers in Italy and together they followed more than a thousand patients who smoked at least a pack of cigarettes a day for 20 years or more.
Every year, for five years, the patients volunteered to come in for a spiral CT scan and to submit blood samples. If a tumor showed up in one of those scans, doctors then cross-checked their blood work. That’s when they noticed two important patterns.
“With this method, we can determine that a tumor is developing, long before a spiral CT could see it, but we also get an indication of how bad that small tumor is. So, we can also define which patients are likely to be cured, versus the ones that might not.”
Doctors need to do more work on the blood test before it’s ready for wide-spread use, but already they are seeing the potential. What was once thought impossible in lung cancer a few short years ago, may now be on the horizon.
“Just by looking at their blood we can say which patient is developing a malignancy and could detect changes in the blood long before the tumor is invasive and metastatic” Croce said. What’s more, he added, “there are not only implications with this approach for lung cancer, but also for other malignancies.”
Dr. Croce’s study appeared in the journal Proceedings of the National Academy of Sciences.**
*Common Cancer Types, National Cancer Institute, July 2011. Online: http://www.cancer.gov/cancertopics/types/commoncancers
**MicroRNA signatures in tissues and plasma predict development and prognosis of computed tomography detected lung cancer, Proceedings of the National Academy of Sciences, Volume 108, Number 9, March 1, 2011. Online: http://www.pnas.org/content/108/9/3713.full