Abstract
The increased amount of free-circulating DNA is present in blood of non-small cell lung cancer (NSCLC) patients, most likely due to up-regulated cell death processes. We believe that dynamics of plasma DNA changes monitored throughout treatment and follow-up period might prove useful for assessment of therapy effectiveness in NSCLC. We analyzed plasma DNA concentrations in 50 NSCLC patients prior and following the radical treatment (stage I-IIIA) or chemotherapy (IIIB), using qPCR method. In order to determine a potential contribution of chronic respiratory inflammation to this phenomenon the levels of plasma DNA were analyzed in 30 COPD, 30 sarcoidosis and 30 persistent asthma patients as well.
Only resectable NSCLC (12.1 ng/ml), but not advanced NSCLC (4.4 ng/ml) group, showed significantly higher mean plasma DNA concentration with respect to patients with chronic respiratory inflammation (3.9 ng/ml) and 30 healthy controls (2.8 ng/ml; p<0.001). Furthermore, a drastic increase in plasma DNA levels up to mean 68.74 ng/ml was observed a week after primary tumor resection or 24/48 hours after chemotherapy administration (16.4 ng/ml). Most resected NSCLC patients with no disease recurrence during 6-12 month follow-up demonstrated reduced plasma DNA levels (2.4 ng/ml) with respect to their presurgical values.
Increased plasma DNA level in NSCLC patients is due to the cancer but not chronic inflammatory process. Drastic raise in plasma DNA levels observed after radical therapy are most likely due to the surgical trauma. Importantly, a trend towards reduction of free-circulating DNA concentration was observed in relapse-free patients. The effect of chemotherapy on plasma DNA in NSCLC IIIB patients is currently analyzed.
- © 2011 ERS