Blood Test Shows Cancer Recurrence Months before Scans

Cancer cells that enter the blood stream are known as circulating tumor cells, or CTCs. CTC counts through a simple blood test, allowing for more frequent and less invasive follow-up.

Scientists at the Perelman School of Medicine enrolled 48 patients with stage II-III locally advanced non-small cell lung cancer (NSCLC) were enrolled in the prospective clinical trial. All patients were treated with concurrent chemoradiation. Blood samples were obtained before treatment, during treatment (at weeks 2, 4 and 6) and following treatment (at months 1, 3, 6, 12, 18 and 24).

Patients ranged in age from 31 to 84, with a median age of 66 years. No patient had a history of prior malignancy. The team also assessed patient gender (54% male), race (69% Caucasian, 21% African American), smoking status (77% former, 21% current), histology (48% squamous cell carcinoma, 46% adenocarcinoma) and median primary tumor size was 3.7 cm. Circulating tumor cells were identified by analyzing the samples with an adenoviral probe that detects elevated activity of a specific enzyme that is produced when cancer cells replicate.

The investigators reported that 15/20 patients had elevated CTC counts following treatment, with a median lead time of 4.7 months and a range of 1.2 months to one year. Of these 15 patients, two-thirds demonstrated a rise in CTC counts an average of six months before Positron emission tomography (PET) and/or computerized tomography (CT) scans detected the recurrence. For many patients, CTC levels were negative immediately following treatment but rose subsequently in the months following treatment. While most of these CTC level rises occurred before disease recurrence was identified on imaging, four of the 20 patients experienced recurrences that were detected with imaging before elevated CTC levels indicated the disease had returned.

Charles B. Simone, II, MD, the study’s senior author and principal investigator, said, “The future use of circulating tumor cells as a diagnostic and prognostic tool for localized NSCLC looks promising. Although imaging remains the cornerstone of post-treatment surveillance for patients, blood tests could, and perhaps should, be used in conjunction with imaging scans to better monitor patients during their follow-up period after treatment.” The study was presented on March 16, at the 2017 Multidisciplinary Thoracic Cancers Symposium held in San Francisco, CA, USA.