In an interview on the study “Sentinel Circulating Tumor Cells Allow Early Diagnosis of Lung Cancer in Patients with Chronic Obstructive Pulmonary Disease,” lead author Paul Hofman, MD, discusses the patient population and the 5 patients who were diagnosed early with lung cancer and treated successfully, thanks to ISET circulating tumor cell (CTC) identification.
Q: In the study, the five Chronic Obstructive Pulmonary Disease (COPD) patients identified with ISET as having CTC ranged in age from 47 to 63 with an average age of 52.8. Is that unusually young for these cells to first appear?
PH: We sought to find CTC in 245 subjects without cancer, including 168 with COPD. So, only a small portion had CTCs at the time of the study. But, we do know that tumors shed cancer cells into the blood at the very earliest point in their development—long before the tumors can be perceived using diagnostic imaging.
Q: According to the American Cancer Society, the average age of a patient diagnosed with lung cancer in the U.S. is 70. Could these cancers be detected 20 years earlier using the ISET technology?
PH: Keep in mind that lung cancer is a “silent cancer,” in that it has very few symptoms in stages 1 and 2. This, in fact, is why the cancer is so deadly. Most patients first learn that they have lung cancer long after tumor cells have mobilized and moved to distant parts of the body. So, these cancers can take root and go undetected for many years.
We know CTC detection by ISET can help better manage patients who have already been diagnosed with tumors. What is so promising with this latest study is the hope it provides to those who have not yet been diagnosed.
All 5 who tested positive for CTCs using ISET were tested in 2008-2009. These five received annual CT scans so that the suspected cancer could be visualized as quickly as possible. Removing small lung tumors before they have too much time to metastasize provides the best outcomes for these patients. The first patients showed visible signs of a small lung tumor, or nodule, in 2010. That tumor was at Stage 1A and when it was removed it was 1.5 cm, very small. Two more patients showed nodule growth in 2012 and the last two in 2013. All tumors were removed during Stage 1A and none grew larger than 2 cm.
Q: All five patients had COPD and were diagnosed with the condition in their 30s and 40s. Is that unusual?
PH: COPD is very common among chronic smokers. The average age of COPD patients at the time of diagnosis in France is about 45, which reflects the fact that smoking is much more pervasive here than in the U.S. It is not uncommon in France to see very young people, starting as early as age 12 or 13, who smoke regularly. That may have once been true in the U.S., but no longer. I completed my post-doctoral position at Brigham & Women’s Hospital in Boston 18 years ago. I remember vividly returning to France and being surprised by how many more people smoked in France compared to the U.S.